Fabrication of Hybrid Materials for Catalysis

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Catalysts catalysts	3.8	6.8	2011	13.9 Days	CHF 2200
Hydrogen hydrogen	-	3.6	2020	14.8 Days	CHF 1000
Molecules molecules	4.2	7.4	1996	15.1 Days	CHF 2700
Nanomaterials nanomaterials	4.4	8.5	2010	14.1 Days	CHF 2400
Physchem physchem	-	1.4	2021	24.2 Days	CHF 1000

14 pages, 2978 KiB

Open AccessCommunication

In Situ Synthesis of Ternary Ni-Fe-Mo Nanosheet Arrays for OER in Water Electrolysis

by Zhi Lu, Yifan Guo, Shilin Li, Jiaqi Ding, Yingzi Ren, Kun Tang, Jiefeng Wang, Chengxin Li, Zishuo Shi, Ziqi Sun, Hongbo Meng and Guangxin Wang

Molecules 2025, 30(1), 177; https://doi.org/10.3390/molecules30010177 - 4 Jan 2025

Cited by 1 | Viewed by 1157

Abstract

Water electrolysis is a promising path to the industrialization development of hydrogen energy. The exploitation of high-efficiency and inexpensive catalysts become important to the mass use of water decomposition. Ni-based nanomaterials have exhibited great potential for the catalysis of water splitting, which have [...] Read more.

Water electrolysis is a promising path to the industrialization development of hydrogen energy. The exploitation of high-efficiency and inexpensive catalysts become important to the mass use of water decomposition. Ni-based nanomaterials have exhibited great potential for the catalysis of water splitting, which have attracted the attention of researchers around the world. Here, we prepared a novel Mo-doped NiFe-based layered double hydroxide (LDH) with a nanoarray microstructure on Ni foam. The doping amount of Mo can significantly change the microstructure of the electrocatalysis, which will further affect the oxygen evolution reaction (OER) performance of water splitting. This novel nanomaterial required only an overpotential of 227 mV for 10 mA cm⁻² and a Tafel slope of 54.8 mV/dec in 1 M KOH. Meanwhile, there was no Mo, and the NiFe-LDH needed 233 mV to attain to 10 mA cm⁻². Compared to the NiFe-LDH without Mo, the NiFeMo-LDH nanosheet arrays exhibited enhanced activities with 17.1 mV/dec less Tafel in OER. The good performance of the electrocatalyst is ascribed to the special nanosheet arrays and the heterostructure of the Ni-Fe-Mo system. These features help to increase the active surface, enhancing the efficient charge transfer and the reactive activity in OER. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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10 pages, 2516 KiB

Open AccessArticle

Self-Assembly Regulated Photocatalysis of Porphyrin-TiO₂ Nanocomposites

by Yisheng Liu, Xinpeng Lv, Yong Zhong, Gaoyang Wang, Shuanghong Liu, Sudi Chen, Cai Qi, Mu He, Ping Shangguan, Zhengqun Luo, Xi Li, Jincheng Guo, Jiajie Sun, Feng Bai and Jiefei Wang

Molecules 2024, 29(16), 3872; https://doi.org/10.3390/molecules29163872 - 15 Aug 2024

Cited by 1 | Viewed by 1256

Abstract

Photoactive artificial nanocatalysts that mimic natural photoenergy systems can yield clean and renewable energy. However, their poor photoabsorption capability and disfavored photogenic electron–hole recombination hinder their production. Herein, we designed two nanocatalysts with various microstructures by combining the tailored self-assembly of the meso-tetra(p-hydroxyphenyl) [...] Read more.

Photoactive artificial nanocatalysts that mimic natural photoenergy systems can yield clean and renewable energy. However, their poor photoabsorption capability and disfavored photogenic electron–hole recombination hinder their production. Herein, we designed two nanocatalysts with various microstructures by combining the tailored self-assembly of the meso-tetra(p-hydroxyphenyl) porphine photosensitizer with the growth of titanium dioxide (TiO₂). The porphyrin photoabsorption antenna efficiently extended the absorption range of TiO₂ in the visible region, while anatase TiO₂ promoted the efficient electron–hole separation of porphyrin. The photo-induced electrons were transferred to the surface of the Pt co-catalyst for the generation of hydrogen via water splitting, and the hole was utilized for the decomposition of methyl orange dye. The hybrid structure showed greatly increased photocatalytic performance compared to the core@shell structure due to massive active sites and increased photo-generated electron output. This controlled assembly regulation provides a new approach for the fabrication of advanced, structure-dependent photocatalysts. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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22 pages, 12534 KiB

Open AccessArticle

Preparation of Fenton Catalysts for Water Treatment

by Wei Chen, Mei Zeng and Junjiao Yang

Catalysts 2023, 13(11), 1407; https://doi.org/10.3390/catal13111407 - 30 Oct 2023

Cited by 2 | Viewed by 2273

Abstract

In the heterogeneous Fenton reaction, a solid catalyst reacts with H₂O₂ to generate highly oxidizing free radicals, that degrade organic pollutants in aqueous solutions. In this study, impregnation calcination was used to modify activated carbon and load it with various [...] Read more.

In the heterogeneous Fenton reaction, a solid catalyst reacts with H₂O₂ to generate highly oxidizing free radicals, that degrade organic pollutants in aqueous solutions. In this study, impregnation calcination was used to modify activated carbon and load it with various metal compounds. The synergistic catalysis of the various metal compounds showed improved catalytic activity, and the prepared heterogeneous Fenton catalyst exhibited high catalytic activity, a wide pH range, and good stability. The concentration ratios of the Fenton catalyst impregnation solutions-were as follows: Fe³⁺, Cu²⁺, Mn²⁺, and Ce³⁺ at 0.45, 0.72, 0.19, and 0.11 mol/L, respectively. The optimal sintering temperature of AC impregnation was determined through TGA/DSC, SEM, SEM-EDS, XPS, and XRD testing. At a final calcination temperature of 900 °C, the degradation efficiency of 10 ppm methylene blue reached 98.25% at pH 5 with 5 mM H₂O₂. After ten soaking cycles, the degradation efficiency exceeded 90%. The structure and performance of the catalysts were characterized using EPR, BET, ICP, and UV spectroscopy, demonstrating the excellent performance of the catalyst and providing an improved treatment plan for solving wastewater problems. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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15 pages, 4468 KiB

Open AccessArticle

Solar Photocatalytic Activity of Ba-Doped ZnO Nanoparticles: The Role of Surface Hydrophilicity

by Abdessalem Hamrouni, Marwa Moussa, Nidhal Fessi, Leonardo Palmisano, Riccardo Ceccato, Ali Rayes and Francesco Parrino

Nanomaterials 2023, 13(20), 2742; https://doi.org/10.3390/nano13202742 - 10 Oct 2023

Cited by 9 | Viewed by 2048

Abstract

Bare zinc oxide (ZnO) and Ba-doped ZnO (BZO) samples were prepared by using a simple precipitation method. The effects of Barium doping on the structural, morphological, and optoelectronic properties, as well as on the physico-chemical features of the surface were investigated and correlated [...] Read more.

Bare zinc oxide (ZnO) and Ba-doped ZnO (BZO) samples were prepared by using a simple precipitation method. The effects of Barium doping on the structural, morphological, and optoelectronic properties, as well as on the physico-chemical features of the surface were investigated and correlated with the observed photocatalytic activity under natural solar irradiation. The incorporation of Ba²⁺ ions into the ZnO structure increased the surface area by ca. 14 times and enhanced the hydrophilicity with respect to the bare sample, as demonstrated by infrared spectroscopy and contact angle measurements. The surface hydrophilicity was correlated with the enhanced defectivity of the doped sample, as indicated by X-ray diffraction, Raman, and fluorescence spectroscopies. The resulting higher affinity with water was, for the first time, invoked as an important factor justifying the superior photocatalytic performance of BZO compared to the undoped one, in addition to the slightly higher separation of the photoproduced pairs, an effect that has already been reported in literature. In particular, observed kinetic constants values of 8∙10⁻³ and 11.3∙10⁻³ min⁻¹ were determined for the ZnO and BZO samples, respectively, by assuming first order kinetics. Importantly, Ba doping suppressed photocorrosion and increased the stability of the BZO sample under irradiation, making it a promising photocatalyst for the abatement of toxic species. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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14 pages, 4480 KiB

Open AccessArticle

Fabricating BiOCl Nanoflake/FeOCl Nanospindle Heterostructures for Efficient Visible-Light Photocatalysis

by Heng Guo, Yangzhou Deng, Haoyong Yin, Juanjuan Liu and Shihui Zou

Molecules 2023, 28(19), 6949; https://doi.org/10.3390/molecules28196949 - 6 Oct 2023

Cited by 5 | Viewed by 1804

Abstract

Fabricating heterostructures with abundant interfaces and delicate nanoarchitectures is an attractive approach for optimizing photocatalysts. Herein, we report the facile synthesis of BiOCl nanoflake/FeOCl nanospindle heterostructures through a solution chemistry method at room temperature. Characterizations, including XRD, SEM, TEM, EDS, and XPS, were [...] Read more.

Fabricating heterostructures with abundant interfaces and delicate nanoarchitectures is an attractive approach for optimizing photocatalysts. Herein, we report the facile synthesis of BiOCl nanoflake/FeOCl nanospindle heterostructures through a solution chemistry method at room temperature. Characterizations, including XRD, SEM, TEM, EDS, and XPS, were employed to investigate the synthesized materials. The results demonstrate that the in situ reaction between the Bi precursors and the surface Cl⁻ of FeOCl enabled the bounded nucleation and growth of BiOCl on the surface of FeOCl nanospindles. Stable interfacial structures were established between BiOCl nanoflakes and FeOCl nanospindles using Cl⁻ as the bridge. Regulating the Bi-to-Fe ratios allowed for the optimization of the BiOCl/FeOCl interface, thereby facilitating the separation of photogenerated carriers and accelerating the photocatalytic degradation of RhB. The BiOCl/FeOCl heterostructures with an optimal composition of 15% BiOCl exhibited ~90 times higher visible-light photocatalytic activity than FeOCl. Based on an analysis of the band structures and reactive oxygen species, we propose an S-scheme mechanism to elucidate the significantly enhanced photocatalytic performance observed in the BiOCl/FeOCl heterostructures. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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13 pages, 8380 KiB

Open AccessArticle

A Novel Synthetic 3D Interconnected Porous Carbon-Rich Graphitic Carbon Nitride for Boosting Visible Light Photocatalytic Hydrogen Production and Dye Contaminant Degradation

by Cunzhang Tian, Chunling Li, Congyue Zhao, Dong Liu and Xinping He

Catalysts 2023, 13(10), 1345; https://doi.org/10.3390/catal13101345 - 5 Oct 2023

Cited by 3 | Viewed by 1348

Abstract

The use of photocatalysis to address environmental pollution and energy shortage is an attractive choice. Herein, we successfully synthesized a novel 3D interconnected porous carbon-rich g-C₃N₄ catalyst via facile thermal polymerization to enhance photocatalytic hydrogen production and photodegradation of dye [...] Read more.

The use of photocatalysis to address environmental pollution and energy shortage is an attractive choice. Herein, we successfully synthesized a novel 3D interconnected porous carbon-rich g-C₃N₄ catalyst via facile thermal polymerization to enhance photocatalytic hydrogen production and photodegradation of dye contaminants. Enhanced hydrogen evolution (1956.23 μmol g⁻¹ h⁻¹) and photocatalytic RhB degradation (96.74%) efficiency were achieved with the as-obtained catalysts. Based on the photocatalytic experimental data and characterization analyses, an enhancement mechanism was proposed. The 3D interconnected porous structure endowed the g-C₃N₄ with numerous active sites and a large specific surface area, and the carbon modification facilitated the separation and transfer of the photoinduced charge carriers. Nanoshape engineering and the carbon-rich structure showed a synergetic effect in increasing photocatalytic performance. This study offers an applicable methodology for the exploitation of an economical catalyst to alleviate environmental pollution and energy shortages. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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16 pages, 8938 KiB

Open AccessArticle

Understanding the Plasmonic Effect of Enhanced Photodegradation with Au Nanoparticle Decorated ZnO Nanosheet Arrays under Visible Light Irradiation

by Jun Wang, Dongliang Liu, Shun Yuan, Bo Gao, Lin Cheng, Yu Zhang, Kaijia Chen, Aimin Chen and Lianbi Li

Molecules 2023, 28(19), 6827; https://doi.org/10.3390/molecules28196827 - 27 Sep 2023

Cited by 4 | Viewed by 1364

Abstract

Plasmonic-enhanced photocatalysis using visible light is considered a promising strategy for pollution photodegradation. However, there is still a lack of comprehensive and quantitative understanding of the underlying mechanisms and interactions involved. In this study, we employed a two-step process to fabricate arrays of [...] Read more.

Plasmonic-enhanced photocatalysis using visible light is considered a promising strategy for pollution photodegradation. However, there is still a lack of comprehensive and quantitative understanding of the underlying mechanisms and interactions involved. In this study, we employed a two-step process to fabricate arrays of ZnO nanosheets decorated with Au nanoparticles (Au-ZnO NS). Various characterization techniques were used to examine the morphological, structural, and chemical properties of the fabricated Au-ZnO NS array. Furthermore, we systematically investigated the photocatalytic degradation of methyl orange under visible light irradiation using Au-ZnO NS arrays prepared with varying numbers of photochemical reduction cycles. The results indicated that as the number of photochemical reduction cycles increased, the photodegradation efficiency initially increased but subsequently decreased. Under visible light irradiation, the Au-ZnO NS array obtained via four cycles of photochemical reduction exhibits the highest photocatalytic degradation rate of methyl orange 0.00926 min⁻¹, which is six times higher than that of the ZnO NS array. To gain a better understanding of the plasmonic effect on photodegradation performance, we utilized electromagnetic simulations to quantitatively investigate the enhancement of electric fields in the Au-ZnO NS array. The simulations clearly presented the nonlinear dependencies of electric field intensity on the distribution of Au nanoparticles and the wavelength of radiation light, leading to a nonlinear enhancement of hot electron injection and eventual plasmonic photodegradation. The simulated model, corresponding to four cycles of photochemical reduction, exhibits the highest electric field intensity at 550 nm, which can be attributed to its strong plasmonic effect. This work provides mechanistic insights into plasmonic photocatalysts for utilizing visible light and represents a promising strategy for the rational design of high-performance visible light photocatalysts. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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13 pages, 6964 KiB

Open AccessArticle

Antibacterial Activity and the Mechanism of the Z-Scheme Bi₂MoO₆/Bi₅O₇I Heterojunction under Visible Light

by Zhanqiang Ma, Juan Li, Nan Wang, Wei Guo and Kaiyue Zhang

Molecules 2023, 28(19), 6786; https://doi.org/10.3390/molecules28196786 - 24 Sep 2023

Cited by 5 | Viewed by 1522

Abstract

Z-scheme Bi₂MoO₆/Bi₅O₇I heterojunction was constructed by an in situ solvothermal method, which was composed of Bi₂MoO₆ nanosheets growing on the surface of Bi₅O₇I microrods. The antibacterial activities under [...] Read more.

Z-scheme Bi₂MoO₆/Bi₅O₇I heterojunction was constructed by an in situ solvothermal method, which was composed of Bi₂MoO₆ nanosheets growing on the surface of Bi₅O₇I microrods. The antibacterial activities under illumination towards Escherichia coli (E. coli) were investigated. The Bi₂MoO₆/Bi₅O₇I composites exhibited more outstanding antibacterial performance than pure Bi₂MoO₆ and Bi₅O₇I, and the E. coli (10⁸ cfu/mL) was completely inactivated by BM/BI-3 under 90 min irradiation. Additionally, the experiment of adding scavengers revealed that h⁺, •O₂⁻ and •OH played an important role in the E. coli inactivation process. The E. coli cell membrane was damaged by the oxidation of h⁺, •O₂⁻ and •OH, and the intracellular components (K⁺, DNA) subsequently released, which ultimately triggered the apoptosis of the E. coli cell. The enhanced antibacterial performance of Bi₂MoO₆/Bi₅O₇I heterojunction is due to the formation of Z-scheme heterojunction with the effective charge transfer via the well-contacted interface of Bi₂MoO₆ and Bi₅O₇I. This study provides useful guidance on how to construct Bi₅O₇I-based heterojunction for water disinfection with abundant solar energy. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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18 pages, 16917 KiB

Open AccessArticle

A Novel Vermiculite/TiO₂ Composite: Synergistic Mechanism of Enhanced Photocatalysis towards Organic Pollutant Removal

by Lin Han, Xiaoju Yue, Liying Wen, Mingqing Zhang and Shifeng Wang

Molecules 2023, 28(17), 6398; https://doi.org/10.3390/molecules28176398 - 1 Sep 2023

Cited by 5 | Viewed by 1570

Abstract

There has been increasing concern over water pollution, which poses a threat to human life and health. Absorption by low-cost absorbents is considered to be a cost-effective and efficient route. However, the non-reusability of absorbents greatly limits their applications. In this study, a [...] Read more.

There has been increasing concern over water pollution, which poses a threat to human life and health. Absorption by low-cost absorbents is considered to be a cost-effective and efficient route. However, the non-reusability of absorbents greatly limits their applications. In this study, a novel vermiculite/TiO₂ composite combining the inexpensive absorbent with the commonly used photocatalyst was firstly synthesized via the sol-gel method. On the one hand, the organic pollutants are absorbed by vermiculite and then decomposed through the photocatalysis process, enabling the next round of absorption and creating an absorption–decomposition reusable cycle. On the other hand, the modulation effect of optical and electronic structure on the prepared TiO₂ photocatalyst by the vermiculite incorporation could significantly improve the photocatalytic activity and eventually enhance the aforementioned cyclic degradation capacity. The layer-structured vermiculite (Vt) supports a uniform coverage of TiO₂ at an optimized ratio, providing an optimal adsorption environment and contact area between the photocatalyst and methylene blue (MB) molecules. Vt/TiO₂ heterojunction is formed with Si-O-Ti bonding, at which electrons transfer from Vt to TiO₂, enriching electron density in TiO₂ and favoring its photocatalytic activity. Furthermore, the incorporation of Vt increases the light absorption of TiO₂ in the visible range by narrowing the optical band gap to 1.98 eV, which could promote the generation of photo-excited carriers. In addition, PL measurements revealed that the carrier recombination is substantially suppressed, and the charge separation and migration are greatly enhanced by a factor of 3. As a result, the decomposition rate of MB is substantially increased 5.3-fold, which is ascribed to the synergistic effects of the elevated photocatalysis and the large absorption capacity governed by the chemisorption mechanism of the intra-particle diffusion. These results pave the way for composite design towards efficient, economical, and pragmatic water pollution treatment. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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14 pages, 2510 KiB

Open AccessArticle

Catalytic Selective Oxidation of β-O-4 Bond in Phenethoxybenzene as a Lignin Model Using (TBA)₅[PMo₁₀V₂O₄₀] Nanocatalyst: Optimization of Operational Conditions

by Juan Díaz, Luis R. Pizzio, Gina Pecchi, Cristian H. Campos, Laura Azócar, Rodrigo Briones, Romina Romero, Eduardo Troncoso, Camila Méndez-Rivas, Victoria Melín, Juan C. Murillo-Sierra and David Contreras

Molecules 2023, 28(17), 6368; https://doi.org/10.3390/molecules28176368 - 31 Aug 2023

Cited by 2 | Viewed by 1678

Abstract

The catalytic oxidation of phenethoxybenzene as a lignin model compound with a β-O-4 bond was conducted using the Keggin-type polyoxometalate nanocatalyst (TBA)₅[PMo₁₀V₂O₄₀]. The optimization of the process’s operational conditions was carried out using response surface [...] Read more.

The catalytic oxidation of phenethoxybenzene as a lignin model compound with a β-O-4 bond was conducted using the Keggin-type polyoxometalate nanocatalyst (TBA)₅[PMo₁₀V₂O₄₀]. The optimization of the process’s operational conditions was carried out using response surface methodology. The statistically significant variables in the process were determined using a fractional factorial design. Based on this selection, a central circumscribed composite experimental design was used to maximize the phenethoxybenzene conversion, varying temperature, reaction time, and catalyst load. The optimal conditions that maximized the phenethoxybenzene conversion were 137 °C, 3.5 h, and 200 mg of catalyst. In addition, under the optimized conditions, the Kraft lignin catalytic depolymerization was carried out to validate the effectiveness of the process. The depolymerization degree was assessed by gel permeation chromatography from which a significant decrease in the molar mass distribution Mw from 7.34 kDa to 1.97 kDa and a reduction in the polydispersity index PDI from 6 to 3 were observed. Furthermore, the successful cleavage of the β-O-4 bond in the Kraft lignin was verified by gas chromatography–mass spectrometry analysis of the reaction products. These results offer a sustainable alternative to efficiently converting lignin into valuable products. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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13 pages, 3751 KiB

Open AccessArticle

Core-Shell Composite MIL-101(Cr)@TiO₂ for Organic Dye Pollutants and Vehicle Exhaust

by Lei Wu, Mengmeng Zhao, Xian Xin, Qiuyan Ye, Kun Zhang and Ziwei Wang

Molecules 2023, 28(14), 5530; https://doi.org/10.3390/molecules28145530 - 20 Jul 2023

Cited by 7 | Viewed by 2041

Abstract

MIL-101(Cr)@TiO₂ core-shell composite material was synthesized via the hydrothermal method, where MIL-101(Cr) served as the core and TiO₂ acted as the shell. SEM results revealed that the metal-organic framework core effectively prevented the aggregation of TiO₂ nanoparticles and facilitated their [...] Read more.

MIL-101(Cr)@TiO₂ core-shell composite material was synthesized via the hydrothermal method, where MIL-101(Cr) served as the core and TiO₂ acted as the shell. SEM results revealed that the metal-organic framework core effectively prevented the aggregation of TiO₂ nanoparticles and facilitated their dispersion. Characterization techniques such as XRD, XPS, and TGA were utilized to confirm the successful loading of TiO₂ onto MIL-101(Cr) and its excellent thermal stability. MIL-101(Cr)@TiO₂ was employed in photocatalytic degradation of dye pollutants and vehicle exhaust, and the potential degradation mechanisms were investigated in detail. The results showed that MIL-101(Cr)@TiO₂ exhibited excellent photocatalytic degradation performance towards dye pollutants, with degradation efficiencies of 91.7% and 67.8% achieved for MB and RhB, respectively, under visible light irradiation for 90 min. Furthermore, the photocatalytic degradation of automobile exhaust revealed that the MIL-101(Cr)@TiO₂ composite material also exhibited degradation effects on NO_x, CO, and HC. The degradation efficiency for NO reached 24.2%, indicating its broader applicability. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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12 pages, 2849 KiB

Open AccessArticle

On the Application of an In Situ Catalyst Characterization System (ICCS) and a Mass Spectrometer Detector as Powerful Techniques for the Characterization of Catalysts

by Simón Yunes, Jeffrey Kenvin and Antonio Gil

Physchem 2023, 3(2), 220-231; https://doi.org/10.3390/physchem3020015 - 8 May 2023

Cited by 2 | Viewed by 2955

Abstract

The in situ characterization of catalysts provides important information on the catalyst and the understanding of its catalytic performance and selectivity for a specific reaction. Temperature programmed analyses (TPX) techniques for catalyst characterization reveal the role of the support on the stabilization and [...] Read more.

The in situ characterization of catalysts provides important information on the catalyst and the understanding of its catalytic performance and selectivity for a specific reaction. Temperature programmed analyses (TPX) techniques for catalyst characterization reveal the role of the support on the stabilization and dispersion of the active sites. However, these can be altered at high temperatures since sintering of active species can occur as well as possible carbon deposition which hinders the active species and deactivates the catalyst. The in situ characterization of the spent catalyst, however, may expose the causes of catalyst deactivation. For example, a simple temperature programmed oxidation (TPO) analysis on the spent catalyst may produce CO and CO₂ via a reaction with O₂ at high temperatures and this is a strong indication that deactivation may be due to the deposition of carbon. Other TPX techniques such as temperature programmed reduction (TPR) and pulse chemisorption are also valuable techniques when they are applied in situ to the fresh catalyst and then to the catalyst upon deactivation. In this work, two Ni supported catalysts were considered as examples to elucidate the importance of these techniques in the characterization study of catalysts applied to the reaction of hydrogenation of CO₂. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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16 pages, 3588 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Hybrid Nanomaterial of Graphene Oxide Quantum Dots with Multi-Walled Carbon Nanotubes for Simultaneous Voltammetric Determination of Four DNA Bases

by Qusai Hassan, Chevon Riley, Meissam Noroozifar and Kagan Kerman

Nanomaterials 2023, 13(9), 1509; https://doi.org/10.3390/nano13091509 - 29 Apr 2023

Cited by 1 | Viewed by 2326

Abstract

In this proof-of-concept study, a novel hybrid nanomaterial-based electrochemical sensor was developed for the simultaneous detection of four DNA bases. For the modification of the working electrode surface, graphene oxide quantum dots (GOQDs) were synthesized using a solvothermal method. GOQDs were then used [...] Read more.

In this proof-of-concept study, a novel hybrid nanomaterial-based electrochemical sensor was developed for the simultaneous detection of four DNA bases. For the modification of the working electrode surface, graphene oxide quantum dots (GOQDs) were synthesized using a solvothermal method. GOQDs were then used for the preparation of a hybrid nanomaterial with multi-walled carbon nanotubes (GOQD-MWCNT) using a solvothermal technique for the first time. Transmission electron microscopy (TEM) was used to characterize the GOQDs-MWCNTs. A glassy carbon electrode (GCE) was modified with the GOQDs-MWCNTs using Nafion™ to prepare a GOQD-MWCNT/GCE for the simultaneous determination of four DNA bases in phosphate buffer solution (PBS, pH 7.0) using differential pulse voltammetry (DPV). The calibration plots were linear up to 50, 50, 500, and 500 µM with a limit of detection at 0.44, 0.2, 1.6, and 5.6 µM for guanine (G), adenine (A), thymine (T) and cytosine (C), respectively. The hybrid-modified sensor was used for the determination of G, A, T, and C spiked in the artificial saliva samples with the recovery values ranging from 95.9 to 106.8%. This novel hybrid-modified electrochemical sensor provides a promising platform for the future development of a device for cost-effective and efficient simultaneous detection of DNA bases in real biological and environmental samples. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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18 pages, 5559 KiB

Open AccessArticle

Ultrasound and Microwave-Assisted Synthesis of Hexagonally Ordered Ce-Promoted Mesoporous Silica as Ni Supports for Ethanol Steam Reforming

by Jorge Tovar-Rodriguez, Emiliano Fratini, Piero Baglioni, Carlo Ferrari, José Antonio de los Reyes-Heredia, Yonatan Ramírez-Hernández and Ignacio René Galindo-Esquivel

Nanomaterials 2023, 13(6), 997; https://doi.org/10.3390/nano13060997 - 9 Mar 2023

Cited by 6 | Viewed by 1908

Abstract

Solvothermal synthesis of mesoporous materials based on amphiphilic molecules as structure-directing agents can be enhanced using non-conventional technologies for stirring and thermal activation. Here, we disclose a green synthesis approach for the preparation of cerium-modified hexagonally ordered silica sieves. Ultrasound micromixing enabled us [...] Read more.

Solvothermal synthesis of mesoporous materials based on amphiphilic molecules as structure-directing agents can be enhanced using non-conventional technologies for stirring and thermal activation. Here, we disclose a green synthesis approach for the preparation of cerium-modified hexagonally ordered silica sieves. Ultrasound micromixing enabled us to obtain well-dispersed Ce in the self-assembled silica network and yielded ordered materials with high cerium content (Ce/Si molar ratio = 0.08). Microwave dielectric heating, applied by an innovative open-end coaxial antenna, was used to reduce the overall hydrothermal synthesis time and to improve the surface area and textural properties. These mesoporous materials were used as a Ni catalyst support (10 wt.% metal loading) for the ethanol steam reforming reaction. The new catalysts featured complete ethanol conversion, high H₂ selectivity (65%) and better stability, compared to the same catalyst prepared with magnetic stirring and conventional heating. The Ce-promoted silica sieves offered a suitable support for the controlled growth of nanocarbon that does not result in catalyst deactivation or poisoning after 6 h on stream. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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15 pages, 4320 KiB

Open AccessArticle

A Facile Approach of Fabricating Bifunctional Catalysts for Redox Applications by Uniformly Immobilized Metallic Nanoparticles on NiCr LDH

by Mosaed S. Alhumaimess, Obaid F. Aldosari, Almaha N. Alqhobisi, Laila M. Alhaidari, Afnan Altwala, Linah A. Alzarea and Hassan M. A. Hassan

Nanomaterials 2023, 13(6), 987; https://doi.org/10.3390/nano13060987 - 9 Mar 2023

Cited by 4 | Viewed by 2356

Abstract

This study discloses the development of NiCr LDH, Ag@NiCr LDH, and Pd@NiCr LDH bifunction catalysts using a hydrothermal coprecipitation method followed by sol immobilization of metallic nanoparticles. The structures and morphologies of the synthesized nanocomposites were analyzed using FTIR, XRD, XPS, BET, FESEM-EDX, [...] Read more.

This study discloses the development of NiCr LDH, Ag@NiCr LDH, and Pd@NiCr LDH bifunction catalysts using a hydrothermal coprecipitation method followed by sol immobilization of metallic nanoparticles. The structures and morphologies of the synthesized nanocomposites were analyzed using FTIR, XRD, XPS, BET, FESEM-EDX, and HRTEM. The catalytic effectiveness of the samples was evaluated by tracking the progression of NaBH₄-mediated nitrobenzene (NB) reduction to aniline and CO oxidation using UV-visible spectrophotometry and an infrared gas analyzer, respectively. Pd@NiCr LDH displayed much higher performance for both reactions than the bare NiCr LDH. The catalyst Pd@NiCr LDH showed robust catalytic activity in both the oxidation of carbon monoxide (T_50% (136.1 °C) and T_100% (200.2 °C)) and NaBH₄-mediated nitrobenzene reduction (98.7% conversion and 0.365 min⁻¹ rate constant). The results disclose that the Ni²⁺@ Cr³⁺/Cr⁶⁺ @Pd° ion pairs inside the LDH act as a charge transfer center and hence significantly enhance the catalytic performance. As a result, this research offers the novel NiCr LDH catalyst as a bifunctional catalyst for air depollution control and the organic transformation process. Full article

(This article belongs to the Topic Fabrication of Hybrid Materials for Catalysis)

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