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Keywords = Ag/RGO nanocomposites

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14 pages, 4397 KiB  
Article
High-Sensitivity, Low-Hysteresis, Flexible Humidity Sensors Based on Carboxyl-Functionalized Reduced-Graphene Oxide/Ag Nanoclusters
by Hongping Liang, Lanpeng Guo, Yue Niu, Zilun Tang, Zhenting Zhao, Haijuan Mei, Ru Fang, Chen Liu and Weiping Gong
Nanomaterials 2025, 15(11), 800; https://doi.org/10.3390/nano15110800 - 27 May 2025
Viewed by 463
Abstract
The measurement of humidity is of great significance for precision instruments, semiconductor integrated circuits, and element manufacturing factories. The oxygen-containing groups and noble metals in graphene-based sensing materials can significantly influence their humidity-sensing performance. Herein, 1,3,5-benzenetricarboxylic acid-functionalized reduced graphene oxide (H3BTC-rGO) loaded with [...] Read more.
The measurement of humidity is of great significance for precision instruments, semiconductor integrated circuits, and element manufacturing factories. The oxygen-containing groups and noble metals in graphene-based sensing materials can significantly influence their humidity-sensing performance. Herein, 1,3,5-benzenetricarboxylic acid-functionalized reduced graphene oxide (H3BTC-rGO) loaded with Ag nanocluster nanocomposites (H3BTC-rGO/Ag) was synthesized via a facile one-step reduction method. The H3BTC-rGO/Ag-based sensor exhibited excellent humidity-sensing performance, including a higher sensitivity of 88.9% and a faster response/recovery time of 9 s/16 s towards 50% RH than those of other GO-, rGO-, and H3BTC-rGO-based sensors. The proposed humidity sensor was tested in the range of 0% to 100% RH and showed excellent sensitivity even at a low relative humidity of 0–10% or a high relative humidity of 90–100%. In addition, the H3BTC-rGO/Ag-based sensor had excellent selectivity, reliable repeatability, and good stability over 30 days under different relative humidities. Compared with H3BTC-rGO-200, the H3BTC-rGO/Ag-0.25-based sensor exhibited a low hysteresis of less than ±5% RH. The high performance was ascribed to the high density of the carboxyl groups and good conductivity of H3BTC-rGO, as well as the catalytic role of the Ag nanoclusters, resulting in high water adsorption rates. The potential applications of the H3BTC-rGO/Ag-based humidity sensor in human exhalation monitoring are also discussed. This work provides a reference for the application of graphene-based flexible sensors in monitoring very wet and dry environments. Full article
(This article belongs to the Section 2D and Carbon Nanomaterials)
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16 pages, 3793 KiB  
Article
Composites of Reduced Graphene Oxide Based on Silver Nanoparticles and Their Effect on Breast Cancer Stem Cells
by Babu Vimalanathan, Devasena Thiyagarajan, Ruby Nirmala Mary, Magesh Sachidanandam, Savarimuthu Ignacimuthu, Dhanavathy Gnanasampanthapandian, Johnson Rajasingh and Kanagaraj Palaniyandi
Bioengineering 2025, 12(5), 508; https://doi.org/10.3390/bioengineering12050508 - 11 May 2025
Viewed by 812
Abstract
Graphene and its related nanocomposites have garnered significant interest due to their distinct physiochemical and biological properties. In this study, reduced graphene oxide–silver hybrid nanostructures were synthesized for applications in biomedical nanotechnology, particularly in targeting cancer stem cells (CSCs). A range of analytical [...] Read more.
Graphene and its related nanocomposites have garnered significant interest due to their distinct physiochemical and biological properties. In this study, reduced graphene oxide–silver hybrid nanostructures were synthesized for applications in biomedical nanotechnology, particularly in targeting cancer stem cells (CSCs). A range of analytical techniques, such as X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV–visible absorption spectroscopy (UV–VIS), were employed to characterize graphene oxide (GO), reduced graphene oxide (rGO)–silver nanoparticles (AgNPs), and their composite structures. The GO-rGO-AgNPs exhibited potent anticancer properties as evidenced by cell culture assays, spheroid formation assay, and quantitative RT-PCR analysis. Treatment of breast cancer cells (MCF-7) with GO, rGO, and AgNPs significantly reduced cell proliferation and mammosphere formation. Furthermore, these treatments downregulated the expression of marker genes associated with CSCs in MCF-7 cells. Among the tested materials, rGO-AgNP, sodium citrate-mediated GO-AgNP, and rGO-AgNP nanocomposites demonstrated superior inhibitory effects on cell survival compared to GO alone. These findings suggest that these nanocomposites hold promise as effective and non-toxic therapeutic agents for targeting cancer cells and CSCs, thereby offering a novel approach to cancer treatment. Full article
(This article belongs to the Special Issue Advances in Drug Delivery in Cancer Treatment)
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19 pages, 5626 KiB  
Article
Design and Optimization of MoS2@rGO@NiFeS Nanocomposites for Hybrid Supercapattery Performance and Sensitive Electrochemical Detection
by Aneeqa Yasmeen, Amir Muhammad Afzal, Areej S. Alqarni, Muhammad Waqas Iqbal and Sohail Mumtaz
Molecules 2024, 29(21), 5195; https://doi.org/10.3390/molecules29215195 - 2 Nov 2024
Cited by 1 | Viewed by 1601
Abstract
Metal sulfide-based composites have become increasingly common as materials used for electrodes in supercapacitors because of their excellent conductivity, electrochemical activity, and redox capacity. This study synthesized a composite of NiFeS@MoS2@rGO nanostructure using a simple hydrothermal approach. The synthesized nanocomposite consisted [...] Read more.
Metal sulfide-based composites have become increasingly common as materials used for electrodes in supercapacitors because of their excellent conductivity, electrochemical activity, and redox capacity. This study synthesized a composite of NiFeS@MoS2@rGO nanostructure using a simple hydrothermal approach. The synthesized nanocomposite consisted of the composite of nickel sulfide and iron sulfide doped with MoS2@rGO. A three-electrode cell is employed to investigate the electrochemical properties of the NiFeS@MoS2@rGO electrode. The results demonstrated an optimal specific capacitance of 3188 F/g at 1.4 A/g in a 1 M KOH electrolyte. Furthermore, a supercapattery is designed utilizing NiFeS@MoS2@rGO//AC as the positive electrode and activated carbon (AC) as the negative electrode materials. The resulting supercapattery is designed at a cell voltage of 1.6 V, achieving a specific capacity value of 189 C/g at 1.4 A/g. It also demonstrated an excellent energy density of 55 Wh/kg with an enhanced power density of 3800 W/kg. Furthermore, the hybrid device demonstrated remarkable stability with a cycling stability of 95% over 30,000 charge–discharge cycles at a current density of 1.4 A/g. The supercapattery, which has excellent energy storage capabilities, is used as a power source for operating different portable electronic devices. Full article
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20 pages, 6423 KiB  
Article
Polyindole-Functionalized RGO-NiFe2O4-SiO2 Nanocomposite: A Dual-Functional Nanomaterial for Efficient Antimony Adsorption and Subsequent Application in Supercapacitor
by Mohd Shoeb, Fouzia Mashkoor, Mohmmad Naved Khan and Changyoon Jeong
Polymers 2024, 16(21), 3084; https://doi.org/10.3390/polym16213084 - 31 Oct 2024
Cited by 7 | Viewed by 1374
Abstract
Effective wastewater treatment remains a critical challenge, especially when dealing with hazardous pollutants like antimony (Sb(III)). This study addresses this issue by using innovative nanocomposites to remove Sb(III) ions from water, while simultaneously repurposing the spent adsorbents for energy storage applications. We developed [...] Read more.
Effective wastewater treatment remains a critical challenge, especially when dealing with hazardous pollutants like antimony (Sb(III)). This study addresses this issue by using innovative nanocomposites to remove Sb(III) ions from water, while simultaneously repurposing the spent adsorbents for energy storage applications. We developed reduced graphene oxide-NiFe2O3-SiO2-polyindole nanocomposites (RGO-NiFe2O3-SiO2-PIn NCs) via a hydrothermal synthesis method, achieving a high removal efficiency of 91.84% for Sb(III) ions at an initial concentration of 50 mg/L at pH 8. After adsorption, the exhausted adsorbent was repurposed for energy storage, effectively minimizing secondary pollution. The Sb(III)-loaded adsorbent (RGO-NiFe2O3-SiO2-PIn@SbOx) exhibited excellent performance as an energy storage material, with a specific capacitance (Cs) of 701.36 F/g at a current density of 2 A/g and a retention rate of 80.15% after 10,000 cycles. This dual-purpose approach not only advances wastewater treatment technologies but also contributes to sustainable and economical recycling practices, particularly in the field of energy storage. Full article
(This article belongs to the Special Issue Advanced Polymeric Materials for Wastewater Treatment)
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18 pages, 6764 KiB  
Article
A Facile Synthesis of RGO-Ag2MoO4 Nanocomposites for Efficient Lead Removal from Aqueous Solution
by Mohd Shoeb, Fouzia Mashkoor, Mohmmad Naved Khan and Changyoon Jeong
Molecules 2024, 29(21), 5152; https://doi.org/10.3390/molecules29215152 - 31 Oct 2024
Cited by 2 | Viewed by 1033
Abstract
Efficiently treating wastewater, particularly the elimination of heavy metal ions from water systems, continues to be one of the most pressing and complex challenges in modern environmental management. In this work, reduced graphene oxide coupled silver molybdate binary nanocomposites (RGO-Ag2MoO4 [...] Read more.
Efficiently treating wastewater, particularly the elimination of heavy metal ions from water systems, continues to be one of the most pressing and complex challenges in modern environmental management. In this work, reduced graphene oxide coupled silver molybdate binary nanocomposites (RGO-Ag2MoO4 NCs) have been prepared via hydrothermal method. The crystalline nature and surface properties of the developed RGO-Ag2MoO4 NCs were proved by XRD, FTIR, SEM, and EDS techniques. Adsorption experiments demonstrated that the nanocomposites (NCs) effectively removed Pb(II) ions within 120 min, achieving a maximum removal efficiency ranging from 94.96% to 86.37% for Pb(II) concentrations between 20 and 100 mg/L at pH 6. Kinetic studies showed that the adsorption process followed a pseudo-second order model. Isotherm analysis presented that the Langmuir model provided the greatest fit for the equilibrium data, with a monolayer adsorption capacity of 128.94 mg/g. Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic. The results of this study highlight RGO-Ag2MoO4 NCs as a highly promising and eco-friendly material for the effective elimination of Pb(II) ions from wastewater. Their strong adsorption capacity, coupled with sustainable properties, makes them an efficient solution for addressing lead contamination, offering significant potential for practical applications in water treatment systems. Full article
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23 pages, 5014 KiB  
Article
Design and Performance of CuNi-rGO and Ag-CuNi-rGO Composite Electrodes for Use in Fuel Cells
by Mohamed Shaban, Aya Mohamed, Mohamed G. M. Kordy, Hamad AlMohamadi, M. F. Eissa and Hany Hamdy
Catalysts 2024, 14(8), 551; https://doi.org/10.3390/catal14080551 - 22 Aug 2024
Cited by 2 | Viewed by 1584
Abstract
This work developed new electrocatalysts for direct alcohol oxidation fuel cells (DAFCs) by using graphene and reduced graphene oxides (GO and rGO) as supporting nanomaterials for copper–nickel (CuNi) nanocomposites. The manufacture of CuNi, CuNi-GO, and CuNi-rGO nanocomposites was realized through the adaptation of [...] Read more.
This work developed new electrocatalysts for direct alcohol oxidation fuel cells (DAFCs) by using graphene and reduced graphene oxides (GO and rGO) as supporting nanomaterials for copper–nickel (CuNi) nanocomposites. The manufacture of CuNi, CuNi-GO, and CuNi-rGO nanocomposites was realized through the adaptation of Hummer’s method and hydrothermal techniques, with subsequent analysis using a range of analytical tools. The electrocatalytic behavior of these materials in DAFCs, with methanol and ethanol as the fuels, was scrutinized through various methods, including cyclic voltammetry, linear sweep, chronoamperometry, and electrochemical impedance spectroscopy. This investigation also assessed the stability and charge transfer dynamics. The rGO-based CuNi nanocomposite demonstrated a remarkable performance boost, showing increases of approximately 319.6% for methanol and 252.6% for ethanol oxidation compared to bare CuNi. The integration of silver nanoparticles into the Ag-CuNi-rGO electrode led to a current density surge to 679.3 mA/g, which signifies enhancements of 254.2% and 812.6% relative to the CuNi-rGO and CuNi electrodes, respectively. These enhancements are ascribed to the augmented densities of hot sites and the synergistic interactions within the nanocatalysts. The findings underscore the potential of Ag and rGO as effective supports for CuNi nanocomposites, amplifying their catalytic efficiency in DAFC applications. Full article
(This article belongs to the Section Nanostructured Catalysts)
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21 pages, 8177 KiB  
Article
In Situ Synthesis, Characterization and Photocatalytic Efficacy of Silver-Enhanced MXene and Graphene Nanocomposites
by Kishore Chand, M. Mustafa Azeem, Muhammad Nazim Lakhan, Mukhtiar Ahmed, Muhammad Jehanzaib Aslam and Ahmer Hussain Shah
J. Compos. Sci. 2024, 8(7), 243; https://doi.org/10.3390/jcs8070243 - 26 Jun 2024
Cited by 1 | Viewed by 2349
Abstract
The emergence of 2D materials has significantly expanded the wide range of nanomaterials with diverse applications. Notably, their high conductivity, catalytic efficiency, and hydrophobicity have fueled heightened research interests for water treatment applications. This research aimed to investigate the synthesis and characterization of [...] Read more.
The emergence of 2D materials has significantly expanded the wide range of nanomaterials with diverse applications. Notably, their high conductivity, catalytic efficiency, and hydrophobicity have fueled heightened research interests for water treatment applications. This research aimed to investigate the synthesis and characterization of MXene and reduced graphene oxide (rGO) nanocomposites with silver nanoparticles (Ag) for enhanced catalytic activity in the decomposition of Direct Blue-24 dye. In this study, we employed well-established methods, previously documented in the literature, to prepare two distinct nanocomposites. Novel nanocomposites, namely reduced graphene oxide–silver nanoparticles (rGO–Ag) and MXene–silver nanoparticles (MXene–Ag), were synthesized using the hydrothermal and direct reduction method with an ammoniacal solution (aqueous solution). Comprehensive characterization using advanced tools revealed that the introduced Ag particles integrated seamlessly onto the parent nanofilms of the Carbon derivatives, forming a secondary phase with enhanced catalytic functionality. These nanocomposites demonstrated significant improvements in the catalytic decomposition reactions in simulated wastewater. Verification involved the reduction reaction of Direct Blue-24 dye at known nanocomposite concentrations. The results indicated that MXene–Ag exhibited a superior catalytic activity of 98% in 10 min compared to the rGO–Ag nanocomposite films, which achieved 96% in 35 min. The results indicated that MXene–Ag nanocomposites exhibited a 20–25% increase in catalytic efficiency compared to the rGO–Ag nanocomposites. The outcomes of this research hold promise for practical applications in textile wastewater management and various industrial sectors dealing with mutagenic and carcinogenic chemicals containing azo and/or phthalocyanine products. Full article
(This article belongs to the Special Issue Composite Nanostructures for Energy and Environment Applications)
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15 pages, 13456 KiB  
Article
Spherical Silver Nanoparticles Located on Reduced Graphene Oxide Nanocomposites as Sensitive Electrochemical Sensors for Detection of L-Cysteine
by Fei Hua, Tiancheng Yao and Youzhi Yao
Sensors 2024, 24(6), 1789; https://doi.org/10.3390/s24061789 - 10 Mar 2024
Cited by 6 | Viewed by 2270
Abstract
A new, simple, and effective one-step reduction method was applied to prepare a nanocomposite with spherical polycrystalline silver nanoparticles attached to the surface of reduced graphene oxide (Ag@rGO) at room temperature. Equipment such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron [...] Read more.
A new, simple, and effective one-step reduction method was applied to prepare a nanocomposite with spherical polycrystalline silver nanoparticles attached to the surface of reduced graphene oxide (Ag@rGO) at room temperature. Equipment such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) was used to characterize the morphology and composition of the Ag@rGO nanocomposite. A novel electrochemical sensor for detecting L-cysteine was proposed based on fixing Ag@rGO onto a glassy carbon electrode. The electrocatalytic behavior of the sensor was studied via cyclic voltammetry and amperometry. The results indicate that due to the synergistic effect of graphene with a large surface area, abundant active sites, and silver nanoparticles with good conductivity and high catalytic activity, Ag@rGO nanocomposites exhibit significant electrocatalytic activity toward L-cysteine. Under optimal conditions, the constructed Ag@rGO electrochemical sensor has a wide detection range of 0.1–470 μM for L-cysteine, low detection limit of 0.057 μM, and high sensitivity of 215.36 nA M−1 cm−2. In addition, the modified electrode exhibits good anti-interference, reproducibility, and stability. Full article
(This article belongs to the Section Chemical Sensors)
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12 pages, 3287 KiB  
Article
Hydrogen Peroxide and Dopamine Sensors Based on Electrodeposition of Reduced Graphene Oxide/Silver Nanoparticles
by Yuhang Zhang, Na Li, Bo Liu and Hangyu Zhang
Sensors 2024, 24(2), 355; https://doi.org/10.3390/s24020355 - 7 Jan 2024
Cited by 11 | Viewed by 2384
Abstract
In this work, silver nanoparticles (AgNPs)/reduced graphene oxide (rGO) nanocomposites were electrodeposited on glassy carbon electrodes (GCE) to construct electrochemical sensors for the detection of hydrogen peroxide (H2O2) and dopamine (DA). The AgNPs were synthesized on graphene oxide (GO) [...] Read more.
In this work, silver nanoparticles (AgNPs)/reduced graphene oxide (rGO) nanocomposites were electrodeposited on glassy carbon electrodes (GCE) to construct electrochemical sensors for the detection of hydrogen peroxide (H2O2) and dopamine (DA). The AgNPs were synthesized on graphene oxide (GO) by the hydrothermal method, followed by the reduction of the GO during the electrodeposition process, resulting in the formation of the nanocomposites on the surface of the electrodes. The generation of AgNPs on the graphene sheets was verified by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The AgNPs/rGO/GCE showed a linear response to H2O2 in the range of 5 μM to 620 μM, with a sensitivity of 49 μA mM−1cm−2 and a limit of detection (LOD) of 3.19 μA. The linear response of the AgNPs/rGO/GCE to DA ranged from 1 μM to 276 μM, the sensitivity was 7.86 μA mM−1cm−2, and the LOD was 0.18 μM. Furthermore, DA and H2O2 were detected simultaneously in the same solution without interferences, and the sensors displayed good stability over time. The preparation method for the sensors is relatively eco-friendly, convenient, and efficient, exhibiting great potential for sensitive detection of DA and H2O2. Full article
(This article belongs to the Special Issue Research Progress in Electrochemical Aptasensors and Biosensors)
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20 pages, 5895 KiB  
Article
Fabrications of the Flexible Non-Enzymatic Glucose Sensors Using Au-CuO-rGO and Au-CuO-rGO-MWCNTs Nanocomposites as Carriers
by Shu-Han Liao, Kai-Yi Shiau, Fang-Hsing Wang and Cheng-Fu Yang
Sensors 2023, 23(19), 8029; https://doi.org/10.3390/s23198029 - 22 Sep 2023
Cited by 7 | Viewed by 2270
Abstract
A flexible, non-enzymatic glucose sensor was developed and tested on a polyethylene terephthalate (PET) substrate. The sensor’s design involved printing Ag (silver) as the electrode and utilizing mixtures of either gold–copper oxide-modified reduced graphene oxide (Au-CuO-rGO) or gold–copper oxide-modified reduced graphene oxide-multi-walled carbon [...] Read more.
A flexible, non-enzymatic glucose sensor was developed and tested on a polyethylene terephthalate (PET) substrate. The sensor’s design involved printing Ag (silver) as the electrode and utilizing mixtures of either gold–copper oxide-modified reduced graphene oxide (Au-CuO-rGO) or gold–copper oxide-modified reduced graphene oxide-multi-walled carbon nanotubes (Au-CuO-rGO-MWCNTs) as the carrier materials. A one-pot synthesis method was employed to create a nanocomposite material, consisting of Au-CuO-rGO mixtures, which was then printed onto pre-prepared flexible electrodes. The impact of different weight ratios of MWCNTs (0~75 wt%) as a substitute for rGO was also investigated on the sensing characteristics of Au-CuO-rGO-MWCNTs glucose sensors. The fabricated electrodes underwent various material analyses, and their sensing properties for glucose in a glucose solution were measured using linear sweep voltammetry (LSV). The LSV measurement results showed that increasing the proportion of MWCNTs improved the sensor’s sensitivity for detecting low concentrations of glucose. However, it also led to a significant decrease in the upper detection limit for high-glucose concentrations. Remarkably, the research findings revealed that the electrode containing 60 wt% MWCNTs demonstrated excellent sensitivity and stability in detecting low concentrations of glucose. At the lowest concentration of 0.1 μM glucose, the nanocomposites with 75 wt% MWCNTs showed the highest oxidation peak current, approximately 5.9 μA. On the other hand, the electrode without addition of MWCNTs displayed the highest detection limit (approximately 1 mM) and an oxidation peak current of about 8.1 μA at 1 mM of glucose concentration. Full article
(This article belongs to the Special Issue Functional Nanomaterials in Sensing)
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18 pages, 1440 KiB  
Article
Geometrical Characterisation of TiO2-rGO Field-Effect Transistor as a Platform for Biosensing Applications
by Anis Amirah Alim, Roharsyafinaz Roslan, Sh. Nadzirah, Lina Khalida Saidi, P. Susthitha Menon, Ismail Aziah, Dee Chang Fu, Siti Aishah Sulaiman, Nor Azian Abdul Murad and Azrul Azlan Hamzah
Micromachines 2023, 14(9), 1664; https://doi.org/10.3390/mi14091664 - 25 Aug 2023
Cited by 6 | Viewed by 1977
Abstract
The performance of the graphene-based field-effect transistor (FET) as a biosensor is based on the output drain current (Id). In this work, the signal-to-noise ratio (SNR) was investigated to obtain a high-performance device that produces a higher Id value. Using [...] Read more.
The performance of the graphene-based field-effect transistor (FET) as a biosensor is based on the output drain current (Id). In this work, the signal-to-noise ratio (SNR) was investigated to obtain a high-performance device that produces a higher Id value. Using the finite element method, a novel top-gate FET was developed in a three-dimensional (3D) simulation model with the titanium dioxide-reduced graphene oxide (TiO2-rGO) nanocomposite as the transducer material, which acts as a platform for biosensing application. Using the Taguchi mixed-level method in Minitab software (Version 16.1.1), eighteen 3D models were designed based on an orthogonal array L18 (6134), with five factors, and three and six levels. The parameters considered were the channel length, electrode length, electrode width, electrode thickness and electrode type. The device was fabricated using the conventional photolithography patterning technique and the metal lift-off method. The material was synthesised using the modified sol–gel method and spin-coated on top of the device. According to the results of the ANOVA, the channel length contributed the most, with 63.11%, indicating that it was the most significant factor in producing a higher Id value. The optimum condition for the highest Id value was at a channel length of 3 µm and an electrode size of 3 µm × 20 µm, with a thickness of 50 nm for the Ag electrode. The electrical measurement in both the simulation and experiment under optimal conditions showed a similar trend, and the difference between the curves was calculated to be 28.7%. Raman analyses were performed to validate the quality of TiO2-rGO. Full article
(This article belongs to the Special Issue Advances in MEMS Theory and Applications, 2nd Edition)
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16 pages, 5063 KiB  
Article
Stretchable Sensors: Novel Human Motion Monitoring Wearables
by Chia-Jung Cho, Ping-Yu Chung, Ying-Wen Tsai, Yu-Tong Yang, Shih-Yu Lin and Pin-Shu Huang
Nanomaterials 2023, 13(16), 2375; https://doi.org/10.3390/nano13162375 - 19 Aug 2023
Cited by 5 | Viewed by 2855
Abstract
A human body monitoring system remains a significant focus, and to address the challenges in wearable sensors, a nanotechnology-enhanced strategy is proposed for designing stretchable metal-organic polymer nanocomposites. The nanocomposite comprises reduced graphene oxide (rGO) and in-situ generated silver nanoparticles (AgNPs) within elastic [...] Read more.
A human body monitoring system remains a significant focus, and to address the challenges in wearable sensors, a nanotechnology-enhanced strategy is proposed for designing stretchable metal-organic polymer nanocomposites. The nanocomposite comprises reduced graphene oxide (rGO) and in-situ generated silver nanoparticles (AgNPs) within elastic electrospun polystyrene-butadiene-polystyrene (SBS) fibers. The resulting Sandwich Structure Piezoresistive Woven Nanofabric (SSPWN) is a tactile-sensitive wearable sensor with remarkable performance. It exhibits a rapid response time (less than three milliseconds) and high reproducible stability over 5500 cycles. The nanocomposite also demonstrates exceptional thermal stability due to effective connections between rGO and AgNPs, making it suitable for wearable electronic applications. Furthermore, the SSPWN is successfully applied to human motion monitoring, including various areas of the hand and RGB sensing shoes for foot motion monitoring. This nanotechnology-enhanced strategy shows promising potential for intelligent healthcare, health monitoring, gait detection, and analysis, offering exciting prospects for future wearable electronic products. Full article
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19 pages, 10633 KiB  
Article
Au- or Ag-Decorated ZnO-Rod/rGO Nanocomposite with Enhanced Room-Temperature NO2-Sensing Performance
by Ke Huang, Junfeng Lu, Donglin Li, Xianjia Chen, Dingfeng Jin and Hongxiao Jin
Nanomaterials 2023, 13(16), 2370; https://doi.org/10.3390/nano13162370 - 18 Aug 2023
Cited by 10 | Viewed by 2423
Abstract
To improve the gas sensitivity of reduced oxide graphene (rGO)-based NO2 room-temperature sensors, different contents (0–3 wt%) of rGO, ZnO rods, and noble metal nanoparticles (Au or Ag NPs) were synthesized to construct ternary hybrids that combine the advantages of each component. [...] Read more.
To improve the gas sensitivity of reduced oxide graphene (rGO)-based NO2 room-temperature sensors, different contents (0–3 wt%) of rGO, ZnO rods, and noble metal nanoparticles (Au or Ag NPs) were synthesized to construct ternary hybrids that combine the advantages of each component. The prepared ZnO rods had a diameter of around 200 nm and a length of about 2 μm. Au or Ag NPs with diameters of 20–30 nm were loaded on the ZnO-rod/rGO hybrid. It was found that rGO simply connects the monodispersed ZnO rods and does not change the morphology of ZnO rods. In addition, the rod-like ZnO prevents rGO stacking and makes nanocomposite-based ZnO/rGO achieve a porous structure, which facilitates the diffusion of gas molecules. The sensors’ gas-sensing properties for NO2 were evaluated. The results reveal that Ag@ZnO rods-2% rGO and Au@ZnO rods-2% rGO perform better in low concentrations of NO2 gas, with greater response and shorter recovery time at the ambient temperature. The response and recovery times with 15 ppm NO2 were 132 s, 139 s and 108 s, 120 s, and the sensitivity values were 2.26 and 2.87, respectively. The synergistic impact of ZnO and Au (Ag) doping was proposed to explain the improved gas sensing. The p-n junction formed on the ZnO and rGO interface and the catalytic effects of Au (Ag) NPs are the main reasons for the enhanced sensitivity of Au (Ag)@ZnO rods-2% rGO. Full article
(This article belongs to the Special Issue Chemical-Physical Properties and Applications of Nano-Scaled Oxides)
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12 pages, 3214 KiB  
Article
Porous NiMoO4-NrGO as a Battery-Like Electrode Material for Aqueous Hybrid Supercapacitors
by Shahrzad Arshadi-Rastabi, Rasoul Sarraf-Mamoory, Ghadir Razaz, Nicklas Blomquist, Jonas Örtegren and Håkan Olin
J. Compos. Sci. 2023, 7(6), 217; https://doi.org/10.3390/jcs7060217 - 26 May 2023
Cited by 5 | Viewed by 1911
Abstract
Recently, much research has investigated nanocomposites and their properties for the development of energy storage systems. Supercapacitor performance is usually enhanced by the use of porous electrode structures, which produce a larger surface area for reaction. In this work, a biocompatible polymer of [...] Read more.
Recently, much research has investigated nanocomposites and their properties for the development of energy storage systems. Supercapacitor performance is usually enhanced by the use of porous electrode structures, which produce a larger surface area for reaction. In this work, a biocompatible polymer of starch medium was used to create the porous nanostructure. Two powders, i.e., Nickel molybdate/reduced graphene oxide (NiMoO4-rGO) and Nickel molybdate/nitrogen-doped reduced graphene oxide (NiMoO4-NrGO), were synthesized using the deposition method in a medium containing starch, nickel nitrate salts, sodium molybdate, and graphene oxide powder. In terms of electrochemical performance, the NiMoO4-NrGO electrode displayed a higher specific capacitance, i.e., 932 Fg−1 (466 Cg−1), than the NiMoO4-rGO electrode, i.e., 884 Fg−1 (442 Cg−1), at a current density of 1 Ag−1. In fact, graphene oxide sheets could lose more oxygen groups in the presence of ammonia, resulting in increased electrical conductivity. For the asymmetric supercapacitor of NiMoO4-NrGO//AC, the specific capacitance at 1 Ag−1, energy density, and power density were 101.2 Fg−1 (111.32 Cg−1), 17 Wh kg−1, and 174.4 kW kg−1, respectively. In addition, this supercapacitor material displayed a good cycling stability of over 82%. Full article
(This article belongs to the Special Issue Composites for Energy Storage Applications, Volume II)
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20 pages, 1732 KiB  
Review
Noble Metals Functionalized on Graphene Oxide Obtained by Different Methods—New Catalytic Materials
by Mihaela Iordache, Anisoara Oubraham, Ioan-Sorin Sorlei, Florin Alexandru Lungu, Catalin Capris, Tudor Popescu and Adriana Marinoiu
Nanomaterials 2023, 13(4), 783; https://doi.org/10.3390/nano13040783 - 20 Feb 2023
Cited by 22 | Viewed by 4146
Abstract
In recent years, research has focused on developing materials exhibiting outstanding mechanical, electrical, thermal, catalytic, magnetic and optical properties such as graphene/polymer, graphene/metal nanoparticles and graphene/ceramic nanocomposites. Two-dimensional sp2 hybridized graphene has become a material of choice in research due to the [...] Read more.
In recent years, research has focused on developing materials exhibiting outstanding mechanical, electrical, thermal, catalytic, magnetic and optical properties such as graphene/polymer, graphene/metal nanoparticles and graphene/ceramic nanocomposites. Two-dimensional sp2 hybridized graphene has become a material of choice in research due to the excellent properties it displays electrically, thermally, optically and mechanically. Noble nanomaterials also present special physical and chemical properties and, therefore, they provide model building blocks in modifying nanoscale structures for various applications, ranging from nanomedicine to catalysis and optics. The introduction of noble metal nanoparticles (NPs) (Au, Ag and Pd) into chemically derived graphene is important in opening new avenues for both materials in different fields where they can provide hybrid materials with exceptional performance due to the synergistical result of the specific properties of each of the materials. This review presents the different synthetic procedures for preparing Pt, Ag, Pd and Au NP/graphene oxide (GO) and reduced graphene oxide (rGO) composites. Full article
(This article belongs to the Special Issue Nanomaterials for Chemical Engineering (Volume II))
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