Topic Editors

Prof. Dr. Ki-Hyun Kim
Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Korea
Dr. Deepak Kukkar
Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Korea

Synthesis and Applications of Nanostructured Metals and Metal Oxides

Abstract submission deadline
closed (31 October 2022)
Manuscript submission deadline
31 January 2023
Viewed by
38427

Topic Information

Dear Colleagues,

Nanomaterials have been the frontrunners of the numerous technological advancements in this era of cutting-edge technology. Specifically, nanostructured metals and metal oxides exhibit unique size-tunable properties (e.g., optical, electronic, magnetic, catalytic, and mechanical properties). In addition, the pendant surface functionalities of metals and metal oxides-based nanomaterials also contribute to their interaction and effect on biological systems (e.g., nanotoxicity and drug delivery). As such, the aforementioned properties of metals and metal oxides account for their diverse applications such as environmental remediation (e.g., catalysis, gas sensing, energy storage, and energy harvesting), sensing of diverse targets (e.g., explosives, environmental pollutants, and pathogens), therapeutics (e.g., drug delivery and toxicity) and relevant applications in many other fields (e.g., cosmetics, textile, and food industries). In consideration of the diverse properties and applications of metals and metal oxides-based nanomaterials, we cordially invite you to contribute to this Topic entitled, “Synthesis and applications of nanostructured metals and metal oxides”. The major aim of this Topic is to collect very recent original and innovative reports (original research, communications, or review articles) and developments on the synthesis and applications of metals and metal oxides-based nanomaterials (e.g., noble metal nanoparticles, transition metals and metal oxides, and semiconductor inorganic nanocrystals). Prospective authors may consider the diverse applications of the above-mentioned categories of nanomaterials such as catalysis, sensing of diverse targets (e.g., environmental pollutants, microbes, pathogens, explosives, and many more), energy storage and harvesting, opto-electronics, therapeutics (e.g., drug delivery, diagnosis, and toxicity), and food preservation and food packaging.

Prof. Dr. Ki-Hyun Kim
Dr. Deepak Kukkar
Topic Editors

Keywords

  • metal oxides
  • nanomaterials
  • metal oxide nanomaterials
  • catalysis
  • sensing
  • diagnosis
  • energy storage
  • food Preservation
  • therapeutics

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Applied Sciences
applsci
2.838 3.7 2011 17.4 Days 2300 CHF Submit
Nanomaterials
nanomaterials
5.719 6.6 2011 15.4 Days 2400 CHF Submit
Solids
solids
- - 2020 16.8 Days 1000 CHF Submit
Sensors
sensors
3.847 6.4 2001 16.2 Days 2400 CHF Submit
Chemosensors
chemosensors
4.229 3.4 2013 14.8 Days 1800 CHF Submit

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Published Papers (40 papers)

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Article
Nonlinear Optical Properties of Zinc Oxide Nanoparticle Colloids Prepared by Pulsed Laser Ablation in Distilled Water
Nanomaterials 2022, 12(23), 4220; https://doi.org/10.3390/nano12234220 - 28 Nov 2022
Viewed by 387
Abstract
The nonlinear optical properties of zinc oxide nanoparticles (ZnONPs) in distilled water were measured using a femtosecond laser and the Z-scan technique. The ZnONPs colloids were created by the ablation of zinc bulk in distilled water with a 532 nm Nd: YAG laser. [...] Read more.
The nonlinear optical properties of zinc oxide nanoparticles (ZnONPs) in distilled water were measured using a femtosecond laser and the Z-scan technique. The ZnONPs colloids were created by the ablation of zinc bulk in distilled water with a 532 nm Nd: YAG laser. Transmission electron microscopy, an ultraviolet-visible spectrophotometer, and atomic absorption spectrophotometry were used to determine the size, shape, absorption spectra, and concentration of the ZnONPs colloids. The nonlinear absorption coefficient and nonlinear refractive index were measured at different excitation wavelengths and intensities. The nonlinear absorption coefficient of the ZnONPs colloids was found to be positive, caused by reverse saturable absorption, whereas the nonlinear refractive index was found to be negative due to self-defocusing in the ZnONPs. Both laser parameters, such as excitation wavelength and input intensity, and nanoparticle features, such as concentration and size, were found to influence the nonlinear optical properties of the ZnONPs. Full article
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Article
Antimicrobial Properties of Zinc Oxide Nanoparticles Synthesized from Lavandula pubescens Shoot Methanol Extract
Appl. Sci. 2022, 12(22), 11613; https://doi.org/10.3390/app122211613 - 15 Nov 2022
Viewed by 459
Abstract
We report on employing in vitro biosynthesized ZnO nanoparticles using L. pubescens shoot methanol extract (50 and 100 mg LP–ZnO NPs) to examine their antimicrobial efficacy against Pseudomonas aeruginosa (ATCC27853), Staphylococcus aureus (ATCC 29213), Aspergillus niger (ATCC 16404 NA), and Aspergillus terreus (TCC 10029). [...] Read more.
We report on employing in vitro biosynthesized ZnO nanoparticles using L. pubescens shoot methanol extract (50 and 100 mg LP–ZnO NPs) to examine their antimicrobial efficacy against Pseudomonas aeruginosa (ATCC27853), Staphylococcus aureus (ATCC 29213), Aspergillus niger (ATCC 16404 NA), and Aspergillus terreus (TCC 10029). The formation and stability of the investigated ZnO nanoparticles were proven by transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), UV–vis spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The ZnO nanoparticles were rod-shaped (width: 10.76–30.93 nm). The nanoparticles in dimethyl sulfoxide (DMSO) outperformed their water counterparts in terms of their zones of inhibition (ZIs) (marginal means of 12.5 and 8.19 mm, respectively) and minimum inhibition concentrations (MICs) (means of 4.40 and 8.54 mg/mL, respectively). The ZI means for S. aureus, P. aeruginosa, A. terreus, and A. niger were 10.50, 6.13, 12.5, and 11.5 mm, respectively. When treating S. aureus and P. aeruginosa, the ZI of the 50 mg LP–ZnO NPs in water was better (14 mm), with a lower MIC and lower minimum bactericidal/fungicide concentrations (MBC/MFC) (7.22 and 4.88 mg/mL, respectively) than the ZnO and control drugs. The SEM images showed cellular alterations in the surface shapes after the LP–ZnO-NP treatments. Biosynthesized LP–ZnO NPs could have beneficial antibacterial properties, which could allow for future contributions to the development of new antimicrobial drugs. Full article
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Article
Ultra-Light and Ultra-Low Thermal Conductivity of Elastic Silica Nanofibrous Aerogel with TiO2 Opacifier Particles as Filler
Nanomaterials 2022, 12(22), 3928; https://doi.org/10.3390/nano12223928 - 08 Nov 2022
Viewed by 373
Abstract
The thermal radiation phenomenon is more crucial than other thermal transportation phenomena at elevated temperatures (>300 °C). Therefore, infrared radiation resistance and its performance on thermal conduction of nanofibrous aerogel with Titanium oxide (TiO2) filler have been investigated compared to control [...] Read more.
The thermal radiation phenomenon is more crucial than other thermal transportation phenomena at elevated temperatures (>300 °C). Therefore, infrared radiation resistance and its performance on thermal conduction of nanofibrous aerogel with Titanium oxide (TiO2) filler have been investigated compared to control groups (silica nanofibrous aerogels with and without filler). Nanofibrous aerogel has been produced by electrospun silica nanofibers. Later, TiO2 opacifier and a non-opacifier filled materials were prepared by a solution homogenization method and then freeze-dried to obtain particle-filled nanofibrous aerogel. Moreover, the thermal radiation conductivity of the composite was calculated by numerical simulation, and the effect of the anti-infrared radiation of the TiO2 opacifier was obtained. The fascinating inhibited infrared radiation transmission performance (infrared transmittance ~67% at 3 μm) and excellent thermal insulation effect (thermal conductivity of 0.019 Wm−1K−1 at room temperature) and maximum compressive strengths (3.22 kPa) of silica nanofibrous aerogel with TiO2 opacifier were verified. Excellent thermal insulation, compression and thermal stability properties show its potential for practical application in industrial production. The successful synthesis of this material may shed light on the development of other insulative ceramic aerogels. Full article
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Article
Electrochemical Biosensor Based on Chitosan- and Thioctic-Acid-Modified Nanoporous Gold Co-Immobilization Enzyme for Glycerol Determination
Chemosensors 2022, 10(7), 258; https://doi.org/10.3390/chemosensors10070258 - 02 Jul 2022
Viewed by 697
Abstract
An electrochemical biosensor based on chitosan- and thioctic-acid-modified nanoporous gold (NPG) co-immobilization glycerol kinase (GK) and glycerol-3-phosphate oxidase (GPO) was constructed for glycerol determination in wine. The NPG, with the properties of porous microstructure, large specific surface area, and high conductivity, was beneficial [...] Read more.
An electrochemical biosensor based on chitosan- and thioctic-acid-modified nanoporous gold (NPG) co-immobilization glycerol kinase (GK) and glycerol-3-phosphate oxidase (GPO) was constructed for glycerol determination in wine. The NPG, with the properties of porous microstructure, large specific surface area, and high conductivity, was beneficial for protecting the enzyme from inactivation and denaturation and enhancing electron transfer in the modified electrode. The co-immobilization of the enzyme by chitosan-embedding and thioctic-acid-modified NPG covalent bonding was beneficial for improving the catalytic performance and stability of the enzyme-modified electrode. Ferrocene methanol (Fm) was used as a redox mediator to accelerate the electron transfer rate of the enzyme-modified electrode. The fabricated biosensor exhibited a wide determination range of 0.1–5 mM, low determination limit of 77.08 μM, and high sensitivity of 9.17 μA mM−1. Furthermore, it possessed good selectivity, repeatability, and stability, and could be used for the determination of glycerol in real wine samples. This work provides a simple and novel method for the construction of biosensors, which may be helpful to the application of enzymatic biosensors in different determination scenarios. Full article
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Article
Promising Novel Barium Carbonate One-Dimensional Nanostructures and Their Gas Sensing Application: Preparation and Characterization
Chemosensors 2022, 10(6), 230; https://doi.org/10.3390/chemosensors10060230 - 17 Jun 2022
Viewed by 680
Abstract
Recently, barium carbonate-based nanomaterials have been used for sensor and catalysis applications. The sensing performance can be improved with a suitable one-dimensional nanostructure. In this regard, novel nanosized BaCO3 materials were fabricated by a one-pot designed thermal evaporation system. Ten milligrams of [...] Read more.
Recently, barium carbonate-based nanomaterials have been used for sensor and catalysis applications. The sensing performance can be improved with a suitable one-dimensional nanostructure. In this regard, novel nanosized BaCO3 materials were fabricated by a one-pot designed thermal evaporation system. Ten milligrams of Ba as raw material were used to deposit BaCO3 nanostructures at a pressure of 0.85 torr and a temperature of 850 °C in a partial oxygen atmosphere of the ambient. This simple method for fabricating novel BaCO3 nanostructures is presented here. X-ray diffraction was indexed on the orthorhombic polycrystalline structure of the prepared BaCO3. The nanostructures deposited here could be described as Datura-like structures linked with nanowires of 20–50 nm in diameter and 5 µm in length. The BaCO3 nanostructure prepared by the current method exhibited a semiconductor-like behavior with an activation energy of 0.68 eV. This behavior was ascribed to the nature of the morphology, which may possess large defective points. Thus, this nanostructure was subjected to gas sensing measurements, showing high activity toward NO2 gas. The proposed sensor also underwent deep investigation toward NO2 at various gas concentrations and working. The response and recovery time constants were recorded in the ranges of 6–20 s and 30–150 s, respectively. The sensor showed its reversibility toward NO2 when the sensor signal was repeated at various cycles of various concentrations. The sensor was exposed to different levels of humidity, showing high performance toward NO2 gas at 250 °C. The sensor exhibited fast response and recovery toward NO2 gas. Full article
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Article
Simple Synthesis and Characterization of Shell-Thickness-Controlled Ni/Ni3C Core-Shell Nanoparticles
Nanomaterials 2022, 12(12), 1954; https://doi.org/10.3390/nano12121954 - 07 Jun 2022
Viewed by 664
Abstract
Ni/Ni3C core-shell nanoparticles with an average diameter of approximately 120 nm were carburized via a chemical solution method using triethylene glycol. It was found that over time, the nanoparticles were covered with a thin Ni3C shell measuring approximately 1–4 [...] Read more.
Ni/Ni3C core-shell nanoparticles with an average diameter of approximately 120 nm were carburized via a chemical solution method using triethylene glycol. It was found that over time, the nanoparticles were covered with a thin Ni3C shell measuring approximately 1–4 nm, and each Ni core was composed of poly grains. The saturation magnetization of the core-shell nanopowders decreased in proportion to the amount of Ni3C. The synthesis mechanism of the Ni/Ni3C core-shell nanoparticles was proposed through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analyses. Full article
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Article
Sonochemical-Assisted Biogenic Synthesis of Theophrasite β-Ni(OH)2 Nanocluster Using Chia Seeds Extract: Characterization and Anticancer Activity
Nanomaterials 2022, 12(11), 1919; https://doi.org/10.3390/nano12111919 - 03 Jun 2022
Viewed by 891
Abstract
Theophrasite β-Ni(OH)2 nanocluster were fabricated via the sonochemical-assisted biogenic method using chia seeds extract as a reducing and stabilizing agent. The optical and morphological feature of the synthesized nanocluster was characterized using UV-Vis, FTIR, FE-SEM-EDS, HR-TEM, DLS, XPS, and XRD analysis. According [...] Read more.
Theophrasite β-Ni(OH)2 nanocluster were fabricated via the sonochemical-assisted biogenic method using chia seeds extract as a reducing and stabilizing agent. The optical and morphological feature of the synthesized nanocluster was characterized using UV-Vis, FTIR, FE-SEM-EDS, HR-TEM, DLS, XPS, and XRD analysis. According to FE-SEM and HR-TEM images of the synthesized materials, β-Ni(OH)2 nanocluster illustrates the hexagonal particle shape with an average size of 5.8 nm, while the EDS results confirm the high purity of the synthesized nanocluster. Moreover, the XRD pattern of the synthesized materials shows typical peaks that match the reference pattern of the Theophrasite form of β-Ni(OH)2 with a hexagonal crystal system. The XPS analysis illustrates that the prepared samples exhibit both Ni2+ and Ni3+ with the predominance of Ni2+ species. Additionally the in-vitro cytotoxic activity of β-Ni(OH)2 nanocluster is tested against the MCF7 cell lines (breast cancer cells). The MTT assay results proved that the synthesized β-Ni(OH)2 nanocluster has potent cytotoxic activity against breast cancer cell lines (IC50: 62.7 μg/mL). Full article
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Article
Visible-Light-Driven Ag-Doped BiOBr Nanoplates with an Enhanced Photocatalytic Performance for the Degradation of Bisphenol A
Nanomaterials 2022, 12(11), 1909; https://doi.org/10.3390/nano12111909 - 02 Jun 2022
Cited by 2 | Viewed by 785
Abstract
Based on the low utilization rate of visible light and the high-charge carriers-recombination efficiency of bismuth oxybromide (BiOBr), in this work, noble metal Ag was used to modify BiOBr, and Ag-doped BiOBr nanoplates (Ag-BiOBr) were obtained through a one-step hydrothermal method. Compared with [...] Read more.
Based on the low utilization rate of visible light and the high-charge carriers-recombination efficiency of bismuth oxybromide (BiOBr), in this work, noble metal Ag was used to modify BiOBr, and Ag-doped BiOBr nanoplates (Ag-BiOBr) were obtained through a one-step hydrothermal method. Compared with BiOBr, the absorption edge of Ag-BiOBr showed a redshift from 453 nm to 510 nm, and the absorption efficiency of visible light was, obviously, improved. Bisphenol A (BPA) was chosen as the target pollutant, to evaluate the photocatalytic performance of the samples. Ag0.1-BiOBr showed the highest degradation efficiency. The intrinsic photocatalytic activity of Ag0.1-BiOBr, under visible light, was approximately twice as high as that of BiOBr. In this way, a new visible-light-driven photocatalyst was proposed, to fight against organic pollution, which provides a promising strategy for water and wastewater treatment. Full article
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Article
Removal of Chromium(VI) by Nanoscale Zero-Valent Iron Supported on Melamine Carbon Foam
Nanomaterials 2022, 12(11), 1866; https://doi.org/10.3390/nano12111866 - 30 May 2022
Cited by 1 | Viewed by 728
Abstract
The overuse of chromium (Cr) has significantly negatively impacted human life and environmental sustainability. Recently, the employment of nano zero-valent iron (nZVI) for Cr(VI) removal is becoming an emerging approach. In this study, carbonized melamine foam-supported nZVI composites, prepared by a simple impregnation–carbonization–reduction [...] Read more.
The overuse of chromium (Cr) has significantly negatively impacted human life and environmental sustainability. Recently, the employment of nano zero-valent iron (nZVI) for Cr(VI) removal is becoming an emerging approach. In this study, carbonized melamine foam-supported nZVI composites, prepared by a simple impregnation–carbonization–reduction method, were assessed for efficient Cr(VI) removal. The prepared composites were characterized by XPS, SEM, TEM, BET and XRD. Batch experiments at different conditions revealed that the amount of iron added, the temperature of carbonization and the initial Cr(VI) concentration were critical factors. [email protected] exhibited the highest removal efficiency of 99% Cr(VI) (10 mg/L) at neutral pH among the carbonized melamine foam-supported nZVI composites. Its iron particles were effectively soldered onto the carbonaceous surfaces within the pore networks. Moreover, [email protected] demonstrated remarkable stability (60%, 7 days) in an open environment compared with nZVI particles. Full article
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Communication
Investigating Organic Vapor Sensing Properties of Composite Carbon Nanotube-Zinc Oxide Nanowire
Chemosensors 2022, 10(6), 205; https://doi.org/10.3390/chemosensors10060205 - 29 May 2022
Cited by 2 | Viewed by 998
Abstract
The low operating temperature of nanowire gas sensors along with their high surface-to-volume ratio are two factors that make gas sensors more practical. In this paper, the growth of ZnO nanowires on a vertically aligned CNT forest is reported. The utilized method for [...] Read more.
The low operating temperature of nanowire gas sensors along with their high surface-to-volume ratio are two factors that make gas sensors more practical. In this paper, the growth of ZnO nanowires on a vertically aligned CNT forest is reported. The utilized method for ZnO growth was a rapid microwave-assisted hydrothermal route, which facilitates low-temperature and ultra-fast fabrication. Organic vapor sensing properties of fabricated samples were studied in response to different alcoholic vapors at a wide operating temperature range of 25 to 300 °C. Enhancement of the gas response was observed with increasing operating temperature. Moreover, the effect of the ZnO nanowire length on organic vapor sensing properties of CNT-ZnO samples was investigated. Results proved that CNT-ZnO samples with long ZnO wires exhibit higher sensitivity to examined analytes. Different length ZnO nanowires were attained via variation of the microwave exposure time and power. Fabrication parameters were selected based on numerous runs. The length of ZnO synthesized at each distinct run was calculated based on SEM micrographs of the samples. Full article
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Article
Electric Energy Storage Effect in Hydrated ZrO2-Nanostructured System
Nanomaterials 2022, 12(11), 1783; https://doi.org/10.3390/nano12111783 - 24 May 2022
Viewed by 932
Abstract
The dimensional effect of electric charge storage with a density of up to 270 μF/g by the hydrated ZrO2-nanoparticles system was determined. It was found that the place of localization of different charge carriers is the generalized heterophase boundary-nanoparticles surface. The [...] Read more.
The dimensional effect of electric charge storage with a density of up to 270 μF/g by the hydrated ZrO2-nanoparticles system was determined. It was found that the place of localization of different charge carriers is the generalized heterophase boundary-nanoparticles surface. The supposed mechanism of the effect was investigated using the theory of dispersed systems, the band theory, and the theory of contact phenomena in semiconductors, which consists of the formation of localized electronic states in the nanoparticle material due to donor–acceptor interaction with the adsorption ionic atmosphere. The effect is relevant for modern nanoelectronics, microsystem technology, and printed electronics because it allows overcoming the basic physical restrictions on the size, temperature, and operation frequency of the device, caused by leakage currents. Full article
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Article
A General Way to Fabricate Chain-like Ferrite with Ultralow Conductive Percolation Threshold and Wideband Absorbing Ability
Nanomaterials 2022, 12(9), 1603; https://doi.org/10.3390/nano12091603 - 09 May 2022
Cited by 1 | Viewed by 672
Abstract
The magnetic nanochain-like material has been regards as one of the most promising electromagnetic (EM) absorbing material but remains a challenging. Herein, magnetic chain-like ferrite (included Fe3O4, CoFe2O4 and NiFe2O4) are successfully produced [...] Read more.
The magnetic nanochain-like material has been regards as one of the most promising electromagnetic (EM) absorbing material but remains a challenging. Herein, magnetic chain-like ferrite (included Fe3O4, CoFe2O4 and NiFe2O4) are successfully produced through a general solvothermal method, using PVP as the structural-liking agent. Experimental results confirm the ultimate sample possess a 3-dimensional chain-like structure which are constructed by numerous ferrite’s nanoparticles with ~60 nm in diameter. Their electromagnetic parameters can be also manipulated by such a chain structure, especially the dielectric loss, where a sharply increases can be observed on within a lower filling ratio. It greatly benefits to the EM absorbing property. In this article, the electromagnetic absorption layer made with a lower content of ferrite possess the excellent electromagnetic absorption ability, where the optimized effective absorption band was nearly 6.4 GHz under a thickness of 1.8 mm. Moreover, the filling ratio is only 30 wt%. Our method for designing of chain-like magnetic material can be helpful for producing wideband electromagnetic absorption in a low filling ratio. Full article
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Article
Development of a Simultaneous Process of Surface Modification and Pd Nanoparticle Immobilization of a Polymer Substrate Using Radiation
Nanomaterials 2022, 12(9), 1463; https://doi.org/10.3390/nano12091463 - 25 Apr 2022
Cited by 1 | Viewed by 862
Abstract
Pd nanoparticles were immobilized on an acrylonitrile–butadiene–styrene copolymer (ABS) substrate using ionizing radiation. The samples were prepared by irradiating plastic zipper packs containing ABS substrates and a Pd(NO3)2 aqueous solution with a high-energy electron beam (4.8 MeV). Pd nanoparticles immobilized [...] Read more.
Pd nanoparticles were immobilized on an acrylonitrile–butadiene–styrene copolymer (ABS) substrate using ionizing radiation. The samples were prepared by irradiating plastic zipper packs containing ABS substrates and a Pd(NO3)2 aqueous solution with a high-energy electron beam (4.8 MeV). Pd nanoparticles immobilized on the ABS substrate surfaces were observed using scanning electron microscopy (SEM). The chemical state of Pd was found to be coordinated to a carbonyl group or a metallic state by X-ray photoelectron spectroscopy (XPS) measurements. The peel strength of the Cu film on the Pd/ABS samples was 0.7 N/mm or higher. This result shows that the prepared Pd/ABS samples have high adhesion strength, despite not undergoing treatments such as etching with chromic acid. This method is expected to immobilize metal nanoparticles, not only on plastic plates but also on various other materials. Full article
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Article
An Operando X-ray Absorption Spectroscopy Study on Sensing Characteristics of Vertically Aligned ZnO Thin Film for Methane Gas Sensors
Nanomaterials 2022, 12(8), 1285; https://doi.org/10.3390/nano12081285 - 09 Apr 2022
Cited by 2 | Viewed by 882
Abstract
In this work, a simple, facile growth approach for a vertically aligned ZnO thin film is fabricated and its application towards methane gas sensors is demonstrated. ZnO thin film was prepared by a combination of hydrothermal and sputtering methods. First, a ZnO seed [...] Read more.
In this work, a simple, facile growth approach for a vertically aligned ZnO thin film is fabricated and its application towards methane gas sensors is demonstrated. ZnO thin film was prepared by a combination of hydrothermal and sputtering methods. First, a ZnO seed layer was prepared on the substrate through a sputtering technique, then a ZnO nanorod was fabricated using a hydrothermal method. The surface morphology of the ZnO film was observed by scanning electron microscopy (SEM). A ZnO nanorod coated on the dense seed layer is clearly visible in the SEM image. The average size of the hexagonal-shaped ZnO rod was around 50 nm in diameter, with a thickness of about 1 mm. X-ray absorption near-edge structures (XANES) were recorded to characterize the structural properties of the prepared film. The obtained normalized Zn K-edge XANES of the film showed the characteristic features of ZnO, which agreed well with the standard ZnO sample. The measurement of Zn K-edge XANES was performed simultaneously with the sensing response. The results showed a good correlation between sensor response and ZnO structure under optimal conditions. Full article
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Article
Low-Cost Surface Enhanced Raman Scattering for Bio-Probes
Solids 2022, 3(2), 188-202; https://doi.org/10.3390/solids3020013 - 07 Apr 2022
Cited by 2 | Viewed by 925
Abstract
Raman Spectroscopy is a well-known method for identifying molecules by their spectroscopic “fingerprint”. In Surface Enhanced Raman Scattering (SERS), the presence of nanometallic surfaces in contact with the molecules enormously enhances the spectroscopic signal. Raman enhancing surfaces are often fabricated lithographically or chemically, [...] Read more.
Raman Spectroscopy is a well-known method for identifying molecules by their spectroscopic “fingerprint”. In Surface Enhanced Raman Scattering (SERS), the presence of nanometallic surfaces in contact with the molecules enormously enhances the spectroscopic signal. Raman enhancing surfaces are often fabricated lithographically or chemically, but the throughput is low and the equipment is expensive. In this work a SERS layer was formed by the self-assembly of silver nanospheres from a hexane suspension onto an imprinted thermoplastic sheet (PET). In addition, the SERS layer was transferred and securely bonded to other surfaces. This is an important attribute for probes into solid specimen. Raman spectra were obtained with Rhodamine 6G (R6G) solution concentrations ranging from 1 mm to 1 nm. The methods described here produced robust and sensitive SERS surfaces with inexpensive equipment, readily available materials, and with no chemical or lithographic steps. These may be critical concerns to laboratories faced with diminishing funding resources. Full article
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Article
Antibacterial Activity of Silver and Gold Particles Formed on Titania Thin Films
Nanomaterials 2022, 12(7), 1190; https://doi.org/10.3390/nano12071190 - 02 Apr 2022
Cited by 3 | Viewed by 1238
Abstract
Metal-based nanoparticles with antimicrobial activity are gaining a lot of attention in recent years due to the increased antibiotics resistance. The development and the pathogenesis of oral diseases are usually associated with the formation of bacteria biofilms on the surfaces; therefore, it is [...] Read more.
Metal-based nanoparticles with antimicrobial activity are gaining a lot of attention in recent years due to the increased antibiotics resistance. The development and the pathogenesis of oral diseases are usually associated with the formation of bacteria biofilms on the surfaces; therefore, it is crucial to investigate the materials and their properties that would reduce bacterial attachment and biofilm formation. This work provides a systematic investigation of the physical-chemical properties and the antibacterial activity of TiO2 thin films decorated by Ag and Au nanoparticles (NP) against Veillonella parvula and Neisseria sicca species associated with oral diseases. TiO2 thin films were formed using reactive magnetron sputtering by obtaining as-deposited amorphous and crystalline TiO2 thin films after annealing. Au and Ag NP were formed using a two-step process: magnetron sputtering of thin metal films and solid-state dewetting. The surface properties and crystallographic nature of TiO2/NP structures were investigated by SEM, XPS, XRD, and optical microscopy. It was found that the higher thickness of Au and Ag thin films results in the formation of the enlarged NPs and increased distance between them, influencing the antibacterial activity of the formed structures. TiO2 surface with AgNP exhibited higher antibacterial efficiency than Au nanostructured titania surfaces and effectively reduced the concentration of the bacteria. The process of the observation and identification of the presence of bacteria using the deep learning technique was realized. Full article
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Article
Synthesis of Superionic Conductive Li1+x+yAlxSiyTi2−xP3−yO12 Solid Electrolytes
Nanomaterials 2022, 12(7), 1158; https://doi.org/10.3390/nano12071158 - 31 Mar 2022
Cited by 1 | Viewed by 755
Abstract
Commercial lithium-ion batteries using liquid electrolytes are still a safety hazard due to their poor chemical stability and other severe problems, such as electrolyte leakage and low thermal stability. To mitigate these critical issues, solid electrolytes are introduced. However, solid electrolytes have low [...] Read more.
Commercial lithium-ion batteries using liquid electrolytes are still a safety hazard due to their poor chemical stability and other severe problems, such as electrolyte leakage and low thermal stability. To mitigate these critical issues, solid electrolytes are introduced. However, solid electrolytes have low ionic conductivity and inferior power density. This study reports the optimization of the synthesis of sodium superionic conductor-type Li1.5Al0.3Si0.2Ti1.7P2.8O12 (LASTP) solid electrolyte. The as-prepared powder was calcined at 650 °C, 700 °C, 750 °C, and 800 °C to optimize the synthesis conditions and yield high-quality LASTP powders. Later, LASTP was sintered at 950 °C, 1000 °C, 1050 °C, and 1100 °C to study the dependence of the relative density and ionic conductivity on the sintering temperature. Morphological changes were analyzed using field-emission scanning electron microscopy (FE-SEM), and structural changes were characterized using X-ray diffraction (XRD). Further, the ionic conductivity was measured using electrochemical impedance spectroscopy (EIS). Sintering at 1050 °C resulted in a high relative density and the highest ionic conductivity (9.455 × 10−4 S cm−1). These findings corroborate with the activation energies that are calculated using the Arrhenius plot. Therefore, the as-synthesized superionic LASTP solid electrolytes can be used to design high-performance and safe all-solid-state batteries. Full article
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Review
Recent Trends and Advances of Co3O4 Nanoparticles in Environmental Remediation of Bacteria in Wastewater
Nanomaterials 2022, 12(7), 1129; https://doi.org/10.3390/nano12071129 - 29 Mar 2022
Cited by 3 | Viewed by 1119
Abstract
Antibiotic resistance is a formidable global threat. Wastewater is a contributing factor to the prevalence of antibiotic-resistant bacteria and genes in the environment. There is increased interest evident from research trends in exploring nanoparticles for the remediation of antibiotic-resistant bacteria. Cobalt oxide (Co [...] Read more.
Antibiotic resistance is a formidable global threat. Wastewater is a contributing factor to the prevalence of antibiotic-resistant bacteria and genes in the environment. There is increased interest evident from research trends in exploring nanoparticles for the remediation of antibiotic-resistant bacteria. Cobalt oxide (Co3O4) nanoparticles have various technological, biomedical, and environmental applications. Beyond the environmental remediation applications of degradation or adsorption of dyes and organic pollutants, there is emerging research interest in the environmental remediation potential of Co3O4 nanoparticles and its nanocomposites on antibiotic-resistant and/or pathogenic bacteria. This review focuses on the recent trends and advances in remediation using Co3O4 nanoparticles and its nanocomposites on antibiotic-resistant or pathogenic bacteria from wastewater. Additionally, challenges and future directions that need to be addressed are discussed. Full article
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Article
Chemoresistive Sensors for Cellular Type Discrimination Based on Their Exhalations
Nanomaterials 2022, 12(7), 1111; https://doi.org/10.3390/nano12071111 - 28 Mar 2022
Viewed by 954
Abstract
The detection of volatile organic compounds (VOCs) exhaled by human body fluids is a recent and promising method to reveal tumor formations. In this feasibility study, a patented device, based on nanostructured chemoresistive gas sensors, was employed to explore the gaseous exhalations of [...] Read more.
The detection of volatile organic compounds (VOCs) exhaled by human body fluids is a recent and promising method to reveal tumor formations. In this feasibility study, a patented device, based on nanostructured chemoresistive gas sensors, was employed to explore the gaseous exhalations of tumoral, immortalized, and healthy cell lines, with the aim of distinguishing their VOC patterns. The analysis of the device output to the cell VOCs, emanated at different incubation times and initial plating concentrations, was performed to evaluate the device suitability to identify the cell types and to monitor their growth. The sensors ST25 (based on tin and titanium oxides), STN (based on tin, titanium, and niobium oxides), and TiTaV (based on titanium, tantalum and vanadium oxides) used here, gave progressively increasing responses upon the cell density increase and incubation time; the sensor W11 (based on tungsten oxide) gave instead unreliable responses to all cell lines. All sensors (except for W11) gave large and consistent responses to RKO and HEK293 cells, while they were less responsive to CHO, A549, and CACO-2 ones. The encouraging results presented here, although preliminary, foresee the development of sensor arrays capable of identifying tumor presence and its type. Full article
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Article
Preparation of Hollow Niobium Oxide Nanospheres with Enhanced Catalytic Activity for Oxidative Desulfurization
Nanomaterials 2022, 12(7), 1106; https://doi.org/10.3390/nano12071106 - 28 Mar 2022
Viewed by 975
Abstract
Hollow niobium oxide nanospheres were successfully synthesized by using prepared three-dimensional (3D) mesoporous carbon as the hard template. The 3D mesoporous carbon materials were prepared by using histidine as the carbon source and silica microspheres as the hard template. The samples were characterized [...] Read more.
Hollow niobium oxide nanospheres were successfully synthesized by using prepared three-dimensional (3D) mesoporous carbon as the hard template. The 3D mesoporous carbon materials were prepared by using histidine as the carbon source and silica microspheres as the hard template. The samples were characterized by XRD, BET, SEM, TEM and other methods. The results show that the prepared niobium oxide nanospheres have a hollow spherical structure with an outer diameter of about 45 nm and possess a high specific surface area of 134.3 m2·g−1. Furthermore, the 3D mesoporous carbon materials have a typical porous structure with a high specific surface area of 893 m2·g−1. The hollow niobium oxide nanospheres exhibit high catalytic activity in oxidative desulfurization. Under optimal reaction conditions, the DBT conversion rate of the simulated oil is as high as 98.5%. Finally, a possible reaction mechanism is proposed. Full article
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Article
A Green and Facile Microvia Filling Method via Printing and Sintering of Cu-Ag Core-Shell Nano-Microparticles
Nanomaterials 2022, 12(7), 1063; https://doi.org/10.3390/nano12071063 - 24 Mar 2022
Cited by 1 | Viewed by 1098
Abstract
In this work, we developed an eco-friendly and facile microvia filling method by using printing and sintering of Cu-Ag core-shell nano-microparticles ([email protected] NMPs). Through a chemical reduction reaction in a modified silver ammonia solution with L-His complexing agent, [email protected] NMPs with compact and [...] Read more.
In this work, we developed an eco-friendly and facile microvia filling method by using printing and sintering of Cu-Ag core-shell nano-microparticles ([email protected] NMPs). Through a chemical reduction reaction in a modified silver ammonia solution with L-His complexing agent, [email protected] NMPs with compact and uniform Ag shells, excellent sphericity and oxidation resistance were synthesized. The as-synthesized [email protected] NMPs show superior microvia filling properties to Cu nanoparticles (NPs), Ag NPs, and Cu NMPs. By developing a dense refill method, the porosity of the sintered particles within the microvias was significantly reduced from ~30% to ~10%, and the electrical conductivity is increased about twenty-fold. Combing the [email protected] NMPs and the dense refill method, the microvias could obtain resistivities as low as 7.0 and 6.3 μΩ·cm under the sintering temperatures of 220 °C and 260 °C, respectively. The material and method in this study possess great potentials in advanced electronic applications. Full article
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Article
Catalytic Degradation of Anionic Organic Dye on Greenly Synthesized CuO/ZnO Nanocomposites
Appl. Sci. 2022, 12(6), 2910; https://doi.org/10.3390/app12062910 - 11 Mar 2022
Viewed by 911
Abstract
CuO/ZnO nanocomposites were greenly prepared and tested for the catalytic degradation of methyl orange. The XRD analysis confirmed the existence of CuO and ZnO with crystallite sizes within the range of 15–30 nm. TEM and SEM images showed different morphological properties. The TGA [...] Read more.
CuO/ZnO nanocomposites were greenly prepared and tested for the catalytic degradation of methyl orange. The XRD analysis confirmed the existence of CuO and ZnO with crystallite sizes within the range of 15–30 nm. TEM and SEM images showed different morphological properties. The TGA analysis revealed a good thermal stability of the nanocomposite, with a total loss of less than 18% at a temperature of 700 °C. The nanocomposites were tested for the catalytic degradation of methyl orange under mild conditions with a catalyst mass/wastewater volume of 10 g/3 L, an initial dye concentration of 40 ppm, a pH of 4.5, and a degradation time of 3 h. The best efficiency of 49.1% was achieved by CuO nanoparticles (C), followed by 47.6%, which was obtained by 1C1Z. The degradation efficiency of ZnO (Z) was 16.4%, and it was increased by increasing the CuO precursor in the synthesis mixture, while adding ZnO to the CuO, resulting in a decrease in its catalytic performance. Full article
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Article
Mechanism of Photocurrent Degradation and Contactless Healing in p-Type Mg-Doped Gallium Nitride Thin Films
Nanomaterials 2022, 12(6), 899; https://doi.org/10.3390/nano12060899 - 09 Mar 2022
Cited by 2 | Viewed by 1293
Abstract
Light-induced degradation (LID) phenomenon is commonly found in optoelectronics devices. Self-healing effect in halide lead perovskite solar cells was investigated since the electrons and holes in the shallow traps could escape easily at room temperature. However, the degradation in the semiconductors could not [...] Read more.
Light-induced degradation (LID) phenomenon is commonly found in optoelectronics devices. Self-healing effect in halide lead perovskite solar cells was investigated since the electrons and holes in the shallow traps could escape easily at room temperature. However, the degradation in the semiconductors could not easily recover at room temperature, and many of them needed annealing at temperatures in the several hundreds, which was not friendly to the integrated optoelectronic semiconductor devices. To solve this problem, in this work, LID effect of photocurrent in p-type Mg-doped gallium nitride thin films was investigated, and deep defect and vacancy traps played a vital role in the LID and healing process. This work provides a contactless way to heal the photocurrent behavior to its initial level, which is desirable in integrated devices. Full article
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Article
Production of Size-Controlled Gold Nanoclusters for Vapor–Liquid–Solid Method
Nanomaterials 2022, 12(5), 763; https://doi.org/10.3390/nano12050763 - 24 Feb 2022
Cited by 1 | Viewed by 965
Abstract
This study demonstrated the deposition of size-controlled gold (Au) nanoclusters via direct-current magnetron sputtering and inert gas condensation techniques. The impact of different source parameters, namely, sputtering discharge power, inert gas flow rate, and aggregation length on Au nanoclusters’ size and yield was [...] Read more.
This study demonstrated the deposition of size-controlled gold (Au) nanoclusters via direct-current magnetron sputtering and inert gas condensation techniques. The impact of different source parameters, namely, sputtering discharge power, inert gas flow rate, and aggregation length on Au nanoclusters’ size and yield was investigated. Au nanoclusters’ size and size uniformity were confirmed via transmission electron microscopy. In general, Au nanoclusters’ average diameter increased by increasing all source parameters, producing monodispersed nanoclusters of an average size range of 1.7 ± 0.1 nm to 9.1 ± 0.1 nm. Among all source parameters, inert gas flow rate exhibited a strong impact on nanoclusters’ average size, while sputtering discharge power showed great influence on Au nanoclusters’ yield. Results suggest that Au nanoclusters nucleate via a three-body collision mechanism and grow through a two-body collision mechanism, wherein the nanocluster embryos grow in size due to atomic condensation. Ultimately, the usefulness of the produced Au nanoclusters as catalysts for a vapor–liquid–solid technique was put to test to synthesize the phase change material germanium telluride nanowires. Full article
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Article
ZnO Electrodeposition Model for Morphology Control
Nanomaterials 2022, 12(4), 720; https://doi.org/10.3390/nano12040720 - 21 Feb 2022
Cited by 1 | Viewed by 851
Abstract
In this research, a model for electrodeposition of zinc oxide (ZnO) nanostructures over indium-doped tin-oxide (ITO) glass using pulsed current and zinc chloride as source of zinc was proposed. For the model, reactions kinetics rate constants were evaluated by obtaining the reaction product [...] Read more.
In this research, a model for electrodeposition of zinc oxide (ZnO) nanostructures over indium-doped tin-oxide (ITO) glass using pulsed current and zinc chloride as source of zinc was proposed. For the model, reactions kinetics rate constants were evaluated by obtaining the reaction product solid mass of the various species through time using an electrochemical quartz crystal microbalance (EQCM). To obtain a mathematical model of the electrodeposition using Ansys CFX 2D simulation software, the reaction kinetics rates were used to calculate mass transfer in the volume closest to the surface. The model was applied to the experimental electrodeposition conditions to validate its accuracy. Dense wurtzite nanostructures with controlled morphology were obtained on a indium-doped tin-oxide (ITO) glass. Sample characterization was performed using high-resolution field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) on focused ion beam milled (FIBed) sheets from wurtzite mono-crystals. Average crystallite size was evaluated by X-ray diffraction (XRD) using the Scherrer equation, and superficial areas were evaluated by Brunauer, Emmett, and Teller (BET) method. Through the experimental results, a chemical model was developed for the competing reactions based on the speciation of zinc considering pH evolution, and kinetic constants, on the oxygen rich aqueous environment. Owing to the model, an accurate prediction of thickness and type of electrodeposited layers, under given conditions, is achieved. This allows an excellent control of the optical properties of Wurtzite as a photon absorber, for an efficient separation of the electron-hole pair for conduction of the electric charges formed. The large surface area, and small wurtzite crystallites evenly distributed on the thin film electrodeposited over the ITO conductive layer are promising features for later dye-sensitized photovoltaic cell production. Full article
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Article
Electrochemical Detection of Ascorbic Acid in Oranges at MWCNT-AONP Nanocomposite Fabricated Electrode
Nanomaterials 2022, 12(4), 645; https://doi.org/10.3390/nano12040645 - 15 Feb 2022
Cited by 5 | Viewed by 1123
Abstract
Ascorbic acid (AA) is an essential vitamin in the body, influencing collagen formation, as well as norepinephrine, folic acids, tryptophan, tyrosine, lysine, and neuronal hormone metabolism. This work reports on electrochemical detection of ascorbic acid (AA) in oranges using screen-print carbon electrodes (SPCEs) [...] Read more.
Ascorbic acid (AA) is an essential vitamin in the body, influencing collagen formation, as well as norepinephrine, folic acids, tryptophan, tyrosine, lysine, and neuronal hormone metabolism. This work reports on electrochemical detection of ascorbic acid (AA) in oranges using screen-print carbon electrodes (SPCEs) fabricated with multi-walled carbon nanotube- antimony oxide nanoparticle (MWCNT-AONP) nanocomposite. The nanocomposite-modified electrode displayed enhanced electron transfer and a better electrocatalytic reaction towards AA compared to other fabricated electrodes. The current response at the nanocomposite-modified electrode was four times bigger than the bare electrode. The sensitivity and limit of detection (LOD) at the nanocomposite modified electrode was 0.3663 [AA]/µM and 140 nM, respectively, with linearity from 0.16–0.640 μM and regression value R2 = 0.985, using square wave voltammetry (SWV) for AA detection. Two well-separated oxidation peaks were observed in a mixed system containing AA and serotonin (5-HT); and the sensitivity and LOD were 0.0224 [AA]/µA, and 5.85 µΜ, respectively, with a concentration range from 23 to 100 µM (R2 = 0.9969) for AA detection. The proposed sensor outperformed other AA sensors reported in the literature. The fabricated electrode showed great applicability with excellent recoveries ranging from 99 to 107 %, with a mean relative standard deviation (RSD) value of 3.52 % (n = 3) towards detecting AA in fresh oranges. Full article
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Article
CoO Nanozymes with Multiple Catalytic Activities Regulate Atopic Dermatitis
Nanomaterials 2022, 12(4), 638; https://doi.org/10.3390/nano12040638 - 14 Feb 2022
Cited by 4 | Viewed by 1277
Abstract
Herein, we prepared CoO nanozymes with three types of enzyme catalytic activities for the first time, which have SOD-like, CAT-like, and POD-like catalytic activities. This is the first study to report the preparation of CoO nanoparticles with three types of enzyme catalytic activities [...] Read more.
Herein, we prepared CoO nanozymes with three types of enzyme catalytic activities for the first time, which have SOD-like, CAT-like, and POD-like catalytic activities. This is the first study to report the preparation of CoO nanoparticles with three types of enzyme catalytic activities by the one-pot method. By modifying the surface of CoO nanozymes with a carboxyl group, its biocompatibility enhanced, so it can be used in the field of life sciences. In vitro cytotoxicity and anti-H2O2-induced ROS experiments proved that CoO nanozymes can protect HaCaT cells against ROS and cytotoxicity induced by H2O2. In addition, an atopic dermatitis (AD) mouse model was established by topical application of MC903, which verified the anti-inflammatory effect of CoO nanozymes on the AD mouse model. Traditional drugs for the treatment of AD, such as dexamethasone, have significant side-effects. The side-effects include skin burns, telangiectasias, and even serious drug dependence. CoO nano-enzymes have a low cytotoxicity and its multiple enzyme-like catalytic activities can effectively protect cells and tissues in ROS environments, which proves that CoO nano-enzymes have high application potential in the field of anti-inflammation. Full article
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Article
Silver Nanoparticle Arrays onto Glass Substrates Obtained by Solid-State Thermal Dewetting: A Morphological, Structural and Surface Chemical Study
Nanomaterials 2022, 12(4), 617; https://doi.org/10.3390/nano12040617 - 11 Feb 2022
Viewed by 1099
Abstract
Silver nanoparticles (NPs) on glass substrates were obtained by a solid-state thermal dewetting (SSD) process using vacuum-evaporated-silver precursor layers. An exhaustive investigation of the morphological, structural, and surface chemistry properties by systematically controlling the precursor film thickness, annealing temperature, and time was conducted. [...] Read more.
Silver nanoparticles (NPs) on glass substrates were obtained by a solid-state thermal dewetting (SSD) process using vacuum-evaporated-silver precursor layers. An exhaustive investigation of the morphological, structural, and surface chemistry properties by systematically controlling the precursor film thickness, annealing temperature, and time was conducted. Thin silver films with thicknesses of 40 and 80 nm were deposited and annealed in air by applying a combined heat-up+constant temperature–time program. Temperatures from 300 to 500 °C and times from 0 to 50 min were assayed. SSD promoted the morphological modification of the films, leading to the Ag NPs having a discrete structure. The size, shape, surface density, and inter-nanoparticle distance of the nanoparticles depended on the initial film thickness, annealing temperature, and time, exhibiting a cubic silver structure with a (111) preferred crystallographic orientation. The prepared NPs were found to be highly enriched in the Ag{111}/Ag{110}/Ag{100} equilibrium facets. SSD not only promotes NP formation but also promotes the partial oxidation from Ag to AgO at the surface level. AgO was detected on the surface around the nanoparticles synthesized at 500 °C. Overall, a broad framework has been established that connects process factors to distinguish resultant Ag NP features in order to develop unique silver nanoparticles for specific applications. Full article
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Article
Biosynthesis and Characterizations of Silver Nanoparticles from Annona squamosa Leaf and Fruit Extracts for Size-Dependent Biomedical Applications
Nanomaterials 2022, 12(4), 616; https://doi.org/10.3390/nano12040616 - 11 Feb 2022
Cited by 5 | Viewed by 1336
Abstract
Green synthesis differs in the way that the plant produces chemicals that act as reducing and stabilizing agents, and by adopting this green synthesis, we have synthesized silver nanoparticles (AgNPs) from the leaf and fruit extracts of Annona squamosa (also known as Sharifa), [...] Read more.
Green synthesis differs in the way that the plant produces chemicals that act as reducing and stabilizing agents, and by adopting this green synthesis, we have synthesized silver nanoparticles (AgNPs) from the leaf and fruit extracts of Annona squamosa (also known as Sharifa), where these extracts have played an important role as reducing and capping agents. The nanoparticles were synthesized as the consequence of a reduction that happened between plant extracts and the precursor solution. The prepared AgNPs were then characterized using scanning electron microscopy, UV-Visible spectroscopy, and X-ray diffraction to study their morphology, optical response, and crystallinity. A single distinctive absorption peak of colloidal AgNPs samples was observed at 430 nm and 410 nm for leaf and fruit extract samples, having an optical bandgap of 2.97 eV and 2.88 eV, respectively, with a spherical shape having a diameter in the range of 35–90 nm and 15–50 nm, respectively, whilst XRD studies supported the FCC cubic structure of the mediated AgNPs. These green synthesized AgNPs have a wide variety of uses, particularly in the biomedical domain, where they have the potential to treat numerous diseases and are reported to be efficient against antibacterial, anti-cancer, and anti-diabetic activities. Full article
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Article
Direct Laser Interference Ink Printing Using Copper Metal–Organic Decomposition Ink for Nanofabrication
Nanomaterials 2022, 12(3), 387; https://doi.org/10.3390/nano12030387 - 25 Jan 2022
Cited by 1 | Viewed by 1686
Abstract
In this study, we developed an effective and rapid process for nanoscale ink printing, direct laser interference ink printing (DLIIP), which involves the photothermal reaction of a copper-based metal–organic decomposition ink. A periodically lined copper pattern with a width of 500 nm was [...] Read more.
In this study, we developed an effective and rapid process for nanoscale ink printing, direct laser interference ink printing (DLIIP), which involves the photothermal reaction of a copper-based metal–organic decomposition ink. A periodically lined copper pattern with a width of 500 nm was printed on a 240 μm-wide line at a fabrication speed of 17 mm/s under an ambient environment and without any pre- or post-processing steps. This pattern had a resistivity of 3.5 μΩ∙cm, and it was found to exhibit a low oxidation state that was twice as high as that of bulk copper. These results demonstrate the feasibility of DLIIP for nanoscale copper printing with fine electrical characteristics. Full article
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Article
The Water-Based Synthesis of Platinum Nanoparticles Using KrF Excimer Laser Ablation
Nanomaterials 2022, 12(3), 348; https://doi.org/10.3390/nano12030348 - 22 Jan 2022
Cited by 2 | Viewed by 963
Abstract
Our work presents, for the first time, a comprehensive study of the synthesis of fully metallic platinum nanoparticles (Pt-NPs) involving the ablation process in double distilled water using a KrF excimer laser. To obtain detailed information on Pt-NP morphology and optical properties, prepared [...] Read more.
Our work presents, for the first time, a comprehensive study of the synthesis of fully metallic platinum nanoparticles (Pt-NPs) involving the ablation process in double distilled water using a KrF excimer laser. To obtain detailed information on Pt-NP morphology and optical properties, prepared colloids were characterized using High Resolution Scanning Transmission Electron Microscopy (HR-STEM) with advanced capabilities for Energy Dispersive X-ray Analysis (EDX), UV/Vis optical spectroscopy, and Direct Analysis in Real Time—Mass Spectrometry (DART-MS). The influence of the applied laser fluence and laser repetition rate (RR) values on the characteristics of the obtained Pt-NPs and the ablation process, respectively, were also analyzed. Spherical and spherical-like nanoparticles exhibiting aggregation were produced. The Pt-NP mean size values were between 2.2 ± 1.2 nm and 4.0 ± 1.0 nm, while their interplanar distance measurements showed a face-centered cubic (FFC) Pt lattice (111), as revealed by HR–STEM measurements, for all investigated samples. The smallest mean size of 2.2 nm of the Pt-NPs was obtained using a 2.3 J cm−2 laser fluence at a 10 Hz RR, and the narrowest size distribution of the NPs was obtained with a 2.3 J cm−2 laser fluence at a 40 Hz RR. A linear dependence of the Pt-NP diameters versus the laser repetition rate was found at a constant fluence of 2.3 J cm−2. The proposed eco-friendly synthesis route of Pt-NPs, because of its relative simplicity, has the potential for use in industrial production. Full article
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Article
Facile Synthesis of Silane-Modified Mixed Metal Oxide as Catalyst in Transesterification Processes
Nanomaterials 2022, 12(2), 245; https://doi.org/10.3390/nano12020245 - 13 Jan 2022
Cited by 1 | Viewed by 799
Abstract
The fast depletion of fossil fuels has attracted researchers worldwide to explore alternative biofuels, such as biodiesel. In general, the production of biodiesel is carried out via transesterification processes of vegetable oil with the presence of a suitable catalyst. A mixed metal oxide [...] Read more.
The fast depletion of fossil fuels has attracted researchers worldwide to explore alternative biofuels, such as biodiesel. In general, the production of biodiesel is carried out via transesterification processes of vegetable oil with the presence of a suitable catalyst. A mixed metal oxide has shown to be a very attractive heterogeneous catalyst with a high performance. Most of the mixed metal oxide is made by using the general wetness impregnation method. A simple route to synthesize silane-modified mixed metal oxide (CaO-CuO/C6) catalysts has been successfully developed. A fluorocarbon surfactant and triblock copolymers (EO)106(PO)70(EO)106 were used to prevent the crystal agglomeration of carbonate salts (CaCO3-CuCO3) as the precursor to form CaO-CuO with a definite size and morphology. The materials show high potency as a catalyst in the transesterification process to produce biodiesel. The calcined co-precipitation product has a high crystallinity form, as confirmed by the XRD analysis. The synthesized catalyst was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The mechanism of surface modification and the effects of the catalytic activity were also discussed. The biodiesel purity of the final product was analyzed by gas chromatography. The optimum biodiesel yield was 90.17% using the modified mixed metal oxide CaO-CuO/C6. Full article
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Article
Non-Stacked γ-Fe2O3/[email protected]2 Double-Layer Hollow Nanoparticles for Enhanced Photocatalytic Applications under Visible Light
Nanomaterials 2022, 12(2), 201; https://doi.org/10.3390/nano12020201 - 07 Jan 2022
Cited by 5 | Viewed by 775
Abstract
Herein, a non-stacked γ-Fe2O3/[email protected]2 double-layer hollow nano photocatalyst has been developed with ultrathin nanosheets-assembled double shells for photodegradation phenol. High catalytic performance was found that the phenol could be completely degraded in 135 min under visible light, due [...] Read more.
Herein, a non-stacked γ-Fe2O3/[email protected]2 double-layer hollow nano photocatalyst has been developed with ultrathin nanosheets-assembled double shells for photodegradation phenol. High catalytic performance was found that the phenol could be completely degraded in 135 min under visible light, due to the moderate band edge position (VB at 0.59 eV and CB at −0.66 eV) of the non-stacked γ-Fe2O3/[email protected]2, which can expand the excitation wavelength range into the visible light region and produce a high concentration of free radicals (such as ·OH, ·O2−, holes). Furthermore, the interior of the hollow composite γ-Fe2O3 is responsible for charge generation, and the carbon matrix facilitates charge transfer to the external TiO2 shell. This overlap improved the selection/utilization efficiency, while the unique non-stacked double-layered structure inhibited initial charge recombination over the photocatalysts. This work provides new approaches for photocatalytic applications with γ-Fe2O3/C-based materials. Full article
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Article
Effect of Aluminum Doping Ratios on the Properties of Aluminum-Doped Zinc Oxide Films Deposited by Mist Chemical Vapor Deposition Method Applying for Photocatalysis
Nanomaterials 2022, 12(2), 195; https://doi.org/10.3390/nano12020195 - 07 Jan 2022
Cited by 1 | Viewed by 1079
Abstract
Aluminum-doped zinc oxide film was deposited on a glass substrate by mist chemical vapor deposition method. The influence of different aluminum doping ratios on the structural and optical properties of zinc oxide film was investigated. The XRD results revealed that the diffraction peak [...] Read more.
Aluminum-doped zinc oxide film was deposited on a glass substrate by mist chemical vapor deposition method. The influence of different aluminum doping ratios on the structural and optical properties of zinc oxide film was investigated. The XRD results revealed that the diffraction peak of (101) crystal plane was the dominant peak for the deposited AZO films with the Al doping ratios increasing from 1 wt % to 3 wt %. It was found that the variation of AZO film structures was strongly dependent on the Al/Zn ratios. The intertwined nanosheet structures were obtained when Zn/O ratios were greater than Al/O ratios with the deposition temperature of 400 °C. The optical transmittance of all AZO films was greater than 80% in the visible region. The AZO film deposited with Al doping ratio of 2 wt % showed the highest photocatalytic efficiency between the wavelength of 475 nm and 700 nm, with the high first-order reaction rate of 0.004 min−1 under ultraviolet radiation. The mechanism of the AZO film influenced by aluminum doping ratio during mist chemical vapor deposition process was revealed. Full article
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Article
MOFs-Derived Zn-Based Catalysts in Acetylene Acetoxylation
Nanomaterials 2022, 12(1), 98; https://doi.org/10.3390/nano12010098 - 29 Dec 2021
Cited by 3 | Viewed by 770
Abstract
Metal–organic frameworks (MOFs)-derived materials with a large specific surface area and rich pore structures are favorable for catalytic performance. In this work, MOFs are successfully prepared. Through pyrolysis of MOFs under nitrogen gas, zinc-based catalysts with different active sites for acetylene acetoxylation are [...] Read more.
Metal–organic frameworks (MOFs)-derived materials with a large specific surface area and rich pore structures are favorable for catalytic performance. In this work, MOFs are successfully prepared. Through pyrolysis of MOFs under nitrogen gas, zinc-based catalysts with different active sites for acetylene acetoxylation are obtained. The influence of the oxygen atom, nitrogen atom, and coexistence of oxygen and nitrogen atoms on the structure and catalytic performance of MOFs-derived catalysts was investigated. According to the results, the catalysts with different catalytic activity are Zn-O-C (33%), Zn-O/N-C (27%), and Zn-N-C (12%). From the measurements of X-ray photoelectron spectroscopy (XPS), it can be confirmed that the formation of different active sites affects the electron cloud density of zinc. The electron cloud density of zinc affects the ability to attract CH3COOH, which makes catalysts different in terms of catalytic activity. Full article
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Article
Experimental Pore-Scale Study of a Novel Functionalized Iron-Carbon Nanohybrid for Enhanced Oil Recovery (EOR)
Nanomaterials 2022, 12(1), 103; https://doi.org/10.3390/nano12010103 - 29 Dec 2021
Cited by 6 | Viewed by 704
Abstract
Nanofluid flooding, as a new technique to enhance oil recovery, has recently aroused much attention. The current study considers the performance of a novel iron-carbon nanohybrid to EOR. Carbon nanoparticles was synthesized via the hydrothermal method with citric acid and hybridize with iron [...] Read more.
Nanofluid flooding, as a new technique to enhance oil recovery, has recently aroused much attention. The current study considers the performance of a novel iron-carbon nanohybrid to EOR. Carbon nanoparticles was synthesized via the hydrothermal method with citric acid and hybridize with iron (Fe3O4). The investigated nanohybrid is characterized by its rheological properties (viscosity), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis. The efficiency of the synthetized nanoparticle in displacing heavy oil is initially assessed using an oil–wet glass micromodel at ambient conditions. Nanofluid samples with various concentrations (0.05 wt % and 0.5 wt %) dispersed in a water base fluid with varied salinities were first prepared. The prepared nanofluids provide high stability with no additive such as polymer or surfactant. Before displacement experiments were run, to achieve a better understanding of fluid–fluid and grain–fluid interactions in porous media, a series of sub-pore scale tests—including interfacial tension (IFT), contact angle, and zeta potential—were conducted. Nanofluid flooding results show that the nanofluid with the medium base fluid salinity and highest nanoparticle concertation provides the highest oil recovery. However, it is observed that increasing the nanofluid concentration from 0.05% to 0.5% provided only three percent more oil. In contrast, the lowest oil recovery resulted from low salinity water flooding. It was also observed that the measured IFT value between nanofluids and crude oil is a function of nanofluid concentration and base fluid salinities, i.e., the IFT values decrease with the increase of nanofluid concentration and base fluid salinity reduction. However, the base fluid salinity enhancement leads to wettability alteration towards more water-wetness. The main mechanisms responsible for oil recovery enhancement during nanofluid flooding is mainly attributed to wettability alteration toward water-wetness and micro-dispersion formation. However, the interfacial tension (IFT) reduction using the iron-carbon nanohybrid is also observed but the reduction is not significant. Full article
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Article
Ag–Au Core–Shell Triangular Nanoprisms for Improving p-g-C3N4 Photocatalytic Hydrogen Production
Nanomaterials 2021, 11(12), 3347; https://doi.org/10.3390/nano11123347 - 10 Dec 2021
Cited by 2 | Viewed by 1397
Abstract
Ag–Au core–shell triangular nanoprisms ([email protected] TNPs) have aroused extensive research interest in the field of hydrogen evolution reaction (HER) due to their strong plasmon effect and stability. Here, [email protected] TNPs were fabricated by the galvanic-free replacement method. Then, we loaded them on protonated [...] Read more.
Ag–Au core–shell triangular nanoprisms ([email protected] TNPs) have aroused extensive research interest in the field of hydrogen evolution reaction (HER) due to their strong plasmon effect and stability. Here, [email protected] TNPs were fabricated by the galvanic-free replacement method. Then, we loaded them on protonated g-C3N4 nanoprisms (P–CN) by the electrostatic self-assembly method as an efficient plasmonic photocatalyst for HER. The hydrogen production rate of [email protected] TNPs/P–CN (4.52 mmol/g/h) is 4.1 times higher than that of P–CN (1.11 mmol/g/h) under simulated sunlight irradiation, making it the most competitive material for water splitting. The formed Schottky junction helps to trap the hot electrons generated from [email protected] TNPs, and the well-preserved tips of the [email protected] TNPs can effectively generate an electromagnetic field to inhibit the photogenerated electron–holes pairs recombination. This study suggests that the rational design of [email protected] TNPs by the galvanic-free replacement method is an effective co-catalyst for HER and boosting the additional combination of plasmonic metals and catalyst metals for the enhancement to HER. Full article
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Article
Near-Ambient Pressure XPS and MS Study of CO Oxidation over Model Pd-Au/HOPG Catalysts: The Effect of the Metal Ratio
Nanomaterials 2021, 11(12), 3292; https://doi.org/10.3390/nano11123292 - 04 Dec 2021
Cited by 1 | Viewed by 958
Abstract
In this study, the dependence of the catalytic activity of highly oriented pyrolytic graphite (HOPG)-supported bimetallic Pd-Au catalysts towards the CO oxidation based on the Pd/Au atomic ratio was investigated. The activities of two model catalysts differing from each other in the initial [...] Read more.
In this study, the dependence of the catalytic activity of highly oriented pyrolytic graphite (HOPG)-supported bimetallic Pd-Au catalysts towards the CO oxidation based on the Pd/Au atomic ratio was investigated. The activities of two model catalysts differing from each other in the initial Pd/Au atomic ratios appeared as distinctly different in terms of their ignition temperatures. More specifically, the PdAu-2 sample with a lower Pd/Au surface ratio (~0.75) was already active at temperatures less than 150 °C, while the PdAu-1 sample with a higher Pd/Au surface ratio (~1.0) became active only at temperatures above 200 °C. NAP XPS revealed that the exposure of the catalysts to a reaction mixture at RT induces the palladium surface segregation accompanied by an enrichment of the near-surface regions of the two-component Pd-Au alloy nanoparticles with Pd due to adsorption of CO on palladium atoms. The segregation extent depends on the initial Pd/Au surface ratio. The difference in activity between these two catalysts is determined by the presence or higher concentration of specific active Pd sites on the surface of bimetallic particles, i.e., by the ensemble effect. Upon cooling the sample down to room temperature, the reverse redistribution of the atomic composition within near-surface regions occurs, which switches the catalyst back into inactive state. This observation strongly suggests that the optimum active sites emerge under reaction conditions exclusively, involving both high temperature and a reactive atmosphere. Full article
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Article
Smart Mn7+ Sensing via Quenching on Dual Fluorescence of Eu3+ Complex-Modified TiO2 Nanoparticles
Nanomaterials 2021, 11(12), 3283; https://doi.org/10.3390/nano11123283 - 03 Dec 2021
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Abstract
In this work, titania (TiO2) nanoparticles modified by Eu(TTA)3Phen complexes (ETP) were prepared by a simple solvothermal method developing a fluorescence Mn7+ pollutant sensing system. The characterization results indicate that the ETP cause structural deformation and redshifts of [...] Read more.
In this work, titania (TiO2) nanoparticles modified by Eu(TTA)3Phen complexes (ETP) were prepared by a simple solvothermal method developing a fluorescence Mn7+ pollutant sensing system. The characterization results indicate that the ETP cause structural deformation and redshifts of the UV-visible light absorptions of host TiO2 nanoparticles. The ETP also reduce the crystallinity and crystallite size of TiO2 nanoparticles. Compared with TiO2 nanoparticles modified with Eu3+ (TiO2-Eu3+), TiO2 nanoparticles modified with ETP (TiO2-ETP) exhibit significantly stronger photoluminescence under the excitation of 394 nm. Under UV excitation, TiO2-ETP nanoparticles showed blue and red emission corresponding to TiO2 and Eu3+. In addition, as the concentration of ETP in TiO2 nanoparticles increases, the PL intensity at 612 nm also increases. When ETP-modified TiO2 nanoparticles are added to an aqueous solution containing Mn7+, the fluorescence intensity of both TiO2 and ETP decreases. The evolution of the fluorescence intensity ratio (I1/I2) of TiO2 and ETP is linearly related to the concentration of Mn7+. The sensitivity of fluorescence intensity to Mn7+ concentration enables the design of dual fluorescence ratio solid particle sensors. The method proposed here is simple, accurate, efficient, and not affected by the environmental conditions. Full article
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Article
Biosynthesis of Zinc Oxide Nanoparticles Using Leaf Extract of Prosopis juliflora as Potential Photocatalyst for the Treatment of Paper Mill Effluent
Appl. Sci. 2021, 11(23), 11394; https://doi.org/10.3390/app112311394 - 01 Dec 2021
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Abstract
This paper reports on the manufacture of ZnO nanoparticles (ZnO NPs) from Prosopis juliflora leaf extracts. Various methods of characterization were used, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and transmission electron microscope TEM. ZnO NPs has a [...] Read more.
This paper reports on the manufacture of ZnO nanoparticles (ZnO NPs) from Prosopis juliflora leaf extracts. Various methods of characterization were used, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and transmission electron microscope TEM. ZnO NPs has a hexagonal wurtzite structure with a preferred orientation of 101 planes, according to XRD. The functional groups found in ZnO NPs isolated from leaves are responsible for the FT-IR peaks that correspond to them. The morphology of the produced nanoparticles is a sphere-like form, as shown in the SEM pictures. TEM examination revealed ZnO NPs with a size of 50–55 nm. These ZnO NPs were used to remediate pollutants in paper mill effluents, and they were able to remove 86% of the organic pollutants from the sample at 0.05 mg/L dose and reduce 89% of the organic pollutants during a 5-h reflex time. Meanwhile, for the photocatalysis of paper mill effluents, it has been noted that COD was removed by 74.30%, 63.23%, and 57.96% for the first, second, and third cycles, respectively. Full article
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