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Catalysts, Volume 14, Issue 6 (June 2024) – 49 articles

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10 pages, 814 KiB  
Article
First Principles Study of O2 Dissociative Adsorption on Pt-Skin Pt3Cu(111) Surface
by Yanlin Yu, Huaizhang Gu, Mingan Fu, Ying Wang, Xin Fan, Mingqu Zhang and Guojiang Wu
Catalysts 2024, 14(6), 382; https://doi.org/10.3390/catal14060382 - 14 Jun 2024
Viewed by 12
Abstract
The O2 dissociative adsorption serves as a pivotal criterion for assessing the efficacy of oxygen reduction catalysts. We conducted a systematic investigation into O2 dissociative adsorption on the Pt-skin Pt3Cu(111) surface by means of the density functional theory (DFT). [...] Read more.
The O2 dissociative adsorption serves as a pivotal criterion for assessing the efficacy of oxygen reduction catalysts. We conducted a systematic investigation into O2 dissociative adsorption on the Pt-skin Pt3Cu(111) surface by means of the density functional theory (DFT). The computational findings reveal that the O2 adsorption on Pt-skin Pt3Cu(111) surface exhibits comparatively lower stability when contrasted with that on the Pt(111) surface. For O2 dissociation, two paths have been identified. One progresses from the t-f-b state towards the generation of two oxygen atoms situated within nearest-neighbour hcp sites. The other commences from the t-b-t state, leading to the generation of two oxygen atoms occupying nearest-neighbour fcc sites. Moreover, the analysis of the energy barrier associated with O2 dissociation indicates that O2 on the Pt-skin Pt3Cu(111) surface is more difficult to dissociate than on the Pt(111) surface. This study can offer a valuable guide for the practical application of high-performance oxygen reduction catalysts. Full article
(This article belongs to the Section Computational Catalysis)
20 pages, 975 KiB  
Review
Review of TiO2 as Desulfurization Catalyst for Petroleum
by Zahraa A. Hamza, Jamal J. Dawood and Murtadha Abbas Jabbar
Catalysts 2024, 14(6), 381; https://doi.org/10.3390/catal14060381 - 14 Jun 2024
Viewed by 65
Abstract
In the relentless pursuit of sustainable energy solutions, the petroleum industry faces the imperative challenge of mitigating sulfur emissions. This comprehensive review scrutinizes Titanium Dioxide (TiO2) as an extraordinary catalyst, pushing the boundaries of desulfurization performance in petroleum refining. The abstract [...] Read more.
In the relentless pursuit of sustainable energy solutions, the petroleum industry faces the imperative challenge of mitigating sulfur emissions. This comprehensive review scrutinizes Titanium Dioxide (TiO2) as an extraordinary catalyst, pushing the boundaries of desulfurization performance in petroleum refining. The abstract begins by underscoring the urgent need for advanced desulfurization technologies, driven by stringent environmental mandates and escalating global energy demands. The spotlight then shifts to the unparalleled physicochemical attributes of TiO2, showcasing its inherent advantages such as exceptional surface area, stability, and photocatalytic process. A profound exploration of TiO2’s catalytic mechanisms follows, unraveling its capacity to disintegrate stubborn sulfur–carbon bonds, thereby elevating desulfurization efficiency to unprecedented levels. This review meticulously dissects diverse forms of TiO2, ranging from nanoparticles to mesoporous structures, and provides a critical analysis of their respective strengths and limitations in catalyzing sulfur removal. Delving into operational nuances, this review examines the impact of temperature, pressure, and catalyst loading on TiO2 performance, offering crucial insights for optimizing desulfurization processes. The narrative then unfolds to explore cutting-edge developments in TiO2-based catalysts, encompassing ingenious modifications, composites, and hybrid materials designed to augment catalytic activity and selectivity. Anticipating the road ahead, this review contemplates the challenges and prospects of deploying TiO2 on an industrial scale, pointing toward avenues for future research and development. This abstract encapsulates a wealth of knowledge, serving as an indispensable resource for researchers, engineers, and policymakers navigating the dynamic landscape of sustainable petroleum refining. TiO2 emerges as a transformative force, propelling the industry toward cleaner, greener, and more efficient energy production. Full article
(This article belongs to the Section Environmental Catalysis)
16 pages, 7758 KiB  
Article
Enhanced Orange II Removal Using Fe/Mn/Mg2-LDH Activated Peroxymonosulfate: Synergistic Radical Oxidation and Adsorption
by Yajie Wang, Cui Qiu, Peng Cheng, Yuqing Li, Yunlong Ma, Xiuzhen Tao, Bo Weng and Gilles Mailhot
Catalysts 2024, 14(6), 380; https://doi.org/10.3390/catal14060380 - 14 Jun 2024
Viewed by 102
Abstract
In this study, Fe/Mn/Mg2-LDH was utilized for the first time as a catalyst for peroxymonosulfate (PMS) activation to facilitate the removal of Orange II. This composite was characterized using various techniques, such as XRD, FTIR, SEM-EDS, BET, and XPS. The results [...] Read more.
In this study, Fe/Mn/Mg2-LDH was utilized for the first time as a catalyst for peroxymonosulfate (PMS) activation to facilitate the removal of Orange II. This composite was characterized using various techniques, such as XRD, FTIR, SEM-EDS, BET, and XPS. The results revealed a well-defined lamellar structure of Fe/Mn/Mg2-LDH with a metal molar ratio of Fe/Mn/Mg at 1:1:2. Moreover, the structural stability of Fe/Mn/Mg2-LDH was confirmed through the XRD, FTIR, and SEM. Fe/Mn/Mg2-LDH exhibited a good adsorption capacity towards Orange II and highly efficient PMS activation. The optimal removal efficiency of Orange II (98%) was achieved under the conditions of pH 7.0, [PMS] = 1.0 mmol L−1, [Fe/Mn/Mg₂-LDH] = 1.6 g L−1, and [Orange II] = 50 μM. Additionally, this system demonstrated good adaptability across a wide pH range. The presence of Cl and humic acids (HA) did not significantly inhibit Orange II removal, whereas inhibitory effects were observed in the presence of CO32− and PO43−. The removal mechanism of Orange II was attributed to a synergy of adsorption and oxidation processes, wherein the generated surface radicals (SO4•−ads and HOads) on the surface of the Fe/Mn/Mg2-LDH played a predominant role. Furthermore, the Fe/Mn/Mg2-LDH exhibited good reusability, maintaining a removal rate of 90% over five cycles of recycling. The Fe/Mn/Mg2-LDH/PMS system shows promising potential for the treatment of wastewater contaminated with refractory organic pollutants. Full article
(This article belongs to the Section Environmental Catalysis)
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16 pages, 7158 KiB  
Article
Selection of Putative Polyester Hydrolases from the Metagenome of Los Humeros Geothermal Field by Means of In Silico Probes
by Rocio Solis-Palacios, Graciela Espinosa-Luna, Carolina Peña-Montes, Rodolfo Quintana-Castro, María Guadalupe Sánchez-Otero and Rosa María Oliart-Ros
Catalysts 2024, 14(6), 379; https://doi.org/10.3390/catal14060379 - 14 Jun 2024
Viewed by 88
Abstract
Hydrolases are the most popular enzymes, and among the most valuable in biotechnological applications. Some hydrolases, such as lipases, esterases, proteases, cellulases and amylases, are used in the food industry and the production of biopharmaceuticals, biofuels, biopolymers and detergents. Of special interest are [...] Read more.
Hydrolases are the most popular enzymes, and among the most valuable in biotechnological applications. Some hydrolases, such as lipases, esterases, proteases, cellulases and amylases, are used in the food industry and the production of biopharmaceuticals, biofuels, biopolymers and detergents. Of special interest are those obtained from thermophilic microorganisms. Although there is great microbial diversity in extreme environments, the investigations aimed at detecting and isolating enzymes with potential for polyester degradation such as polyethylene terephthalate (PET) are limited. In this work, we explored the metagenomic library of an oil-enriched soil sample from the “Los Humeros” geothermal field by means of in silico probes in search for enzymes potentially able to degrade polyesters. Using conserved motifs and activity-relevant sites of reported polyester hydrolases, we designed probes that allowed us to identify 6 potential polyester hydrolases in the metagenome. Three-dimensional structure prediction revealed a canonical α/β fold and a cap covering the active site of the enzymes. The catalytic triads were composed of Ser, His and Asp. Structural comparison, substrate binding site analysis and molecular docking suggested their potential as polyester hydrolases, particularly cutinases and PETases. An enzyme, REC98271, was cloned, expressed and characterized, showing thermophilic properties and preference for short-chain substrates. These findings contribute to our understanding of enzyme diversity in “Los Humeros” metagenome and their potential applications in biodegradation and recycling processes. Full article
(This article belongs to the Special Issue New Trends in Industrial Biocatalysis)
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15 pages, 3819 KiB  
Review
Advancements in Materials Science and Photocatalysts for Sustainable Development
by Dhanalakshmi Vadivel, Swetha Suryakumar, Claudio Casella, Andrea Speltini and Daniele Dondi
Catalysts 2024, 14(6), 378; https://doi.org/10.3390/catal14060378 - 14 Jun 2024
Viewed by 144
Abstract
Materials science and catalysis advancements play a critical role in achieving sustainable development by managing environmental, energy, and resource challenges. Catalyst design advancements focus on enhancing selectivity to achieve sustainable chemical reactions, reducing energy consumption. Designing catalysts that are environmentally friendly and biodegradable [...] Read more.
Materials science and catalysis advancements play a critical role in achieving sustainable development by managing environmental, energy, and resource challenges. Catalyst design advancements focus on enhancing selectivity to achieve sustainable chemical reactions, reducing energy consumption. Designing catalysts that are environmentally friendly and biodegradable is increasingly gaining importance. This aligns with the principles of green chemistry and contributes to minimizing the environmental impact of catalytic processes. These advances, taken as a whole, lead to more sustainable and efficient processes in industries ranging from energy production to pollutant removal, fueling the advancement toward a more sustainable future. Photochemistry, that is, the activation of a stable compound (catalyst) into the highly reactive excited state, is of particular importance, since photons—especially when they come from solar light—are a green and renewable resource. This review article has provided the overall idea of the photocatalysts and materials under green chemistry perspective from the standpoint of the concept of sustainable development. Full article
(This article belongs to the Special Issue Photocatalysis and Renewable Materials, 2nd Edition)
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14 pages, 4572 KiB  
Article
Photocatalytic Degradation of Crystal Violet (CV) Dye over Metal Oxide (MOx) Catalysts
by Mohammed Sifat, Eugene Shin, Anthony Schevon, Hugo Ramos, Amol Pophali, Hye-Jung Jung, Gary Halada, Yizhi Meng, Nicholas Olynik, David J. Sprouster and Taejin Kim
Catalysts 2024, 14(6), 377; https://doi.org/10.3390/catal14060377 - 14 Jun 2024
Viewed by 131
Abstract
Crystal violet (CV) is an organic chloride salt and a triphenylmethane dye commonly used in the textile processing industry, also being used as a disinfectant and a biomedical stain. Although CV is widely used, it is carcinogenic to humans and is retained by [...] Read more.
Crystal violet (CV) is an organic chloride salt and a triphenylmethane dye commonly used in the textile processing industry, also being used as a disinfectant and a biomedical stain. Although CV is widely used, it is carcinogenic to humans and is retained by industrial-produced effluent for an extended period. The different types of metal oxide (MOx) have impressive photocatalytic properties, allowing them to be utilized for pollutant degradation. The role of the photocatalyst is to facilitate oxidation and reduction processes by trapping light energy. In this study, we investigated different types of metal oxides, such as titanium dioxide (TiO2), zinc oxide (ZnO), zirconium dioxide (ZrO2), iron (III) oxide (Fe2O3), copper (II) oxide (CuO), copper (I) oxide (Cu2O), and niobium pentoxide (Nb2O5) for the CV decomposition reaction at ambient conditions. For characterization, BET and Raman spectroscopy were applied, providing findings showing that the surface area of the anatase TiO2 and ZnO were 5 m2/g and 12.1 m2/g, respectively. The activity tests over TiO2 and ZnO catalysts revealed that up to ~98% of the dye could be decomposed under UV irradiation in <2 h. The decomposition of CV is directly influenced by various factors, such as the types of MOx, the band gap–water splitting relationship, and the recombination rate of electron holes. Full article
(This article belongs to the Section Catalytic Materials)
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17 pages, 2480 KiB  
Article
Impact of Inorganic Anions on the Photodegradation of Herbicide Residues in Water by UV/Persulfate-Based Advanced Oxidation
by Gabriel Pérez-Lucas, Aitor Campillo and Simón Navarro
Catalysts 2024, 14(6), 376; https://doi.org/10.3390/catal14060376 - 13 Jun 2024
Viewed by 269
Abstract
The removal of pesticides and other organic pollutants from water through advanced oxidation processes (AOPs) holds great promise. The main advantage of these technologies is that they remove, or at least reduce, pesticide levels by mineralization rather than transfer, as in conventional processes. [...] Read more.
The removal of pesticides and other organic pollutants from water through advanced oxidation processes (AOPs) holds great promise. The main advantage of these technologies is that they remove, or at least reduce, pesticide levels by mineralization rather than transfer, as in conventional processes. This study first evaluated the effectiveness of UV/S2O8= compared to heterogeneous photocatalysis using UV/TiO2 processes on the degradation of two commonly used herbicides (terbuthylazine and isoproturon) in aqueous solutions using a laboratory photoreactor. In addition, the effect of the UV wavelength on the degradation efficiency of both herbicides was investigated. Although the degradation rate was greater under UV(254)/S2O8= nm than under UV(365)/S2O8= nm, complete degradation of the herbicides (0.2 mg L−1) was achieved within 30 min under UV-366 nm using a Na2S2O8 dose of 250 mg L−1 in the absence of inorganic anions. To assess the impact of the water matrix, the individual and combined effects of sulfate (SO4=), bicarbonate (HCO3), and chloride (Cl) were evaluated. These can react with hydroxyl (HO) and sulfate (SO4•−) radicals generated during AOPs to form new radicals with a lower redox potential. The results showed negligible effects of SO4=, while the combination of HCO3 and Cl seemed to be the key to the decrease in herbicide removal efficiency found when working with complex matrices. Finally, the main intermediates detected during the photodegradation process are identified, and the likely pathways involving dealkylation, dechlorination, and hydroxylation are proposed and discussed. Full article
(This article belongs to the Special Issue Recent Advances in Photocatalytic Treatment of Pollutants in Water)
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23 pages, 5652 KiB  
Review
Morphology and Microstructural Optimization of Zeolite Crystals Utilizing Polymer Growth Modifiers for Enhanced Catalytic Application
by Junling Zhan, Chongyao Bi, Xiaohui Du, Tao Liu and Mingjun Jia
Catalysts 2024, 14(6), 375; https://doi.org/10.3390/catal14060375 - 12 Jun 2024
Viewed by 191
Abstract
Rationally controlling the morphology and microstructure of the zeolite crystals could play a significant role in optimizing their physicochemical properties and catalytic performances for application in various zeolite-based heterogeneous catalysis processes. Among different controlling strategies, the utilization of zeolite growth modifiers (ZGMs), which [...] Read more.
Rationally controlling the morphology and microstructure of the zeolite crystals could play a significant role in optimizing their physicochemical properties and catalytic performances for application in various zeolite-based heterogeneous catalysis processes. Among different controlling strategies, the utilization of zeolite growth modifiers (ZGMs), which are molecules capable of altering the anisotropic rates of crystal growth, is becoming a promising approach to modulate the morphology and microstructural characteristics of zeolite crystals. In this mini-review, we attempt to provide an organized overview of the recent progress in the usage of several easily available polymer-based growth modifiers in the synthesis of some commonly used microporous zeolites and to reveal their roles in controlling the morphology and various physicochemical properties of zeolite crystals during hydrothermal synthesis processes. This review is expected to provide some guidance for deeply understanding the modulation mechanisms of polymer-based zeolite growth modifiers and for appropriately utilizing such a modulation strategy to achieve precise control of the morphology and microstructure of zeolite crystals that display optimal performance in the target catalytic reactions. Full article
(This article belongs to the Special Issue Surface Microstructure Design for Advanced Catalysts)
20 pages, 7373 KiB  
Review
S-Scheme Heterojunction Photocatalysts for CO2 Reduction
by Mingli Li, He Cui, Yi Zhao, Shunli Li, Jiabo Wang, Kai Ge and Yongfang Yang
Catalysts 2024, 14(6), 374; https://doi.org/10.3390/catal14060374 - 12 Jun 2024
Viewed by 353
Abstract
Photocatalytic technology, which is regarded as a green route to transform solar energy into chemical fuels, plays an important role in the fields of energy and environmental protection. An emerging S-scheme heterojunction with the tightly coupled interface, whose photocatalytic efficiency exceeds those of [...] Read more.
Photocatalytic technology, which is regarded as a green route to transform solar energy into chemical fuels, plays an important role in the fields of energy and environmental protection. An emerging S-scheme heterojunction with the tightly coupled interface, whose photocatalytic efficiency exceeds those of conventional type II and Z-scheme photocatalysts, has received much attention due to its rapid charge carrier separation and strong redox capacity. This review provides a systematic description of S-scheme heterojunction in the photocatalysis, including its development, reaction mechanisms, preparation, and characterization methods. In addition, S-scheme photocatalysts for CO2 reduction are described in detail by categorizing them as 0D/1D, 0D/2D, 0D/3D, 2D/2D, and 2D/3D. Finally, some defects of S-scheme heterojunctions are pointed out, and the future development of S-scheme heterojunctions is proposed. Full article
(This article belongs to the Special Issue Novel Nano-Heterojunctions with Enhanced Catalytic Activity)
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42 pages, 11729 KiB  
Review
Recent Advances of PtCu Alloy in Electrocatalysis: Innovations and Applications
by Ziyang Shen, Jinyao Tang and Xiaochen Shen
Catalysts 2024, 14(6), 373; https://doi.org/10.3390/catal14060373 - 11 Jun 2024
Viewed by 298
Abstract
Developing highly active and durable platinum-based catalysts is crucial for electrochemical renewable energy conversion technologies but the limited supply and high cost of platinum have hindered their widespread implementation. The incorporation of non-noble metals, particularly copper, into Pt catalysts has been demonstrated as [...] Read more.
Developing highly active and durable platinum-based catalysts is crucial for electrochemical renewable energy conversion technologies but the limited supply and high cost of platinum have hindered their widespread implementation. The incorporation of non-noble metals, particularly copper, into Pt catalysts has been demonstrated as an effective solution to reduce Pt consumption while further promoting their performance, making them promising for various electrocatalytic reactions. This review summarizes the latest advances in PtCu-based alloy catalysts over the past several years from both synthetic and applied perspectives. In the synthesis section, the selection of support and reagents, synthesis routes, as well as post-treatment methods at high temperatures are reviewed. The application section focuses not only on newly proposed electrochemical reactions such as nitrogen-related reactions and O2 reduction but also extends to device-level applications. The discussion in this review aims to provide further insights and guidance for the development of PtCu electrocatalysts for practical applications. Full article
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13 pages, 7258 KiB  
Article
Facile Abatement of Oxygenated Volatile Organic Compounds via Hydrogen Co-Combustion over Pd/Al2O3 Catalyst as Onsite Heating Source
by Lutf Ullah, Sehrish Munsif, Long Cao, Jing-Cai Zhang and Wei-Zhen Li
Catalysts 2024, 14(6), 372; https://doi.org/10.3390/catal14060372 - 10 Jun 2024
Viewed by 322
Abstract
Catalytic combustion of volatile organic compounds (VOCs) usually requires external energy input to hold the desired reaction temperature via electric heating. This work presents an example of internal onsite heating of the catalytic active sites via hydrogen catalytic combustion with air over a [...] Read more.
Catalytic combustion of volatile organic compounds (VOCs) usually requires external energy input to hold the desired reaction temperature via electric heating. This work presents an example of internal onsite heating of the catalytic active sites via hydrogen catalytic combustion with air over a conventional Pd/Al2O3 catalyst. Hydrogen combustion was ignited by the catalyst at room temperature without electric heating, and thus the temperatures were readily varied with the concentrations of H2. Representative oxygenated VOCs such as methanol, formaldehyde and formic acid can be completely oxidized into CO2 and water by co-feeding with H2 below its low explosion limit of 4% using Pd/Al2O3 as shared catalyst. The catalytic performance apparently is not sensitive to the sizes of Pd nanoparticles in fresh and spent states, as revealed by XRD and STEM. This provides an option for using renewable green hydrogen to eliminate VOC pollutants in an energy-efficient way. Full article
(This article belongs to the Section Industrial Catalysis)
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24 pages, 2031 KiB  
Review
Strategies to Prepare Chitin and Chitosan-Based Bioactive Structures Aided by Deep Eutectic Solvents: A Review
by D. Alonzo Durante-Salmerón, Isabel Fraile-Gutiérrez, Rubén Gil-Gonzalo, Niuris Acosta, Inmaculada Aranaz and Andrés R. Alcántara
Catalysts 2024, 14(6), 371; https://doi.org/10.3390/catal14060371 - 10 Jun 2024
Viewed by 609
Abstract
Chitin and chitosan, abundant biopolymers derived from the shells of crustaceans and the cell walls of fungi, have garnered considerable attention in pharmaceutical circles due to their biocompatibility, biodegradability, and versatile properties. Deep eutectic solvents (DESs), emerging green solvents composed of eutectic mixtures [...] Read more.
Chitin and chitosan, abundant biopolymers derived from the shells of crustaceans and the cell walls of fungi, have garnered considerable attention in pharmaceutical circles due to their biocompatibility, biodegradability, and versatile properties. Deep eutectic solvents (DESs), emerging green solvents composed of eutectic mixtures of hydrogen bond acceptors and donors, offer promising avenues for enhancing the solubility and functionality of chitin and chitosan in pharmaceutical formulations. This review delves into the potential of utilizing DESs as solvents for chitin and chitosan, highlighting their efficiency in dissolving these polymers, which facilitates the production of novel drug delivery systems, wound dressings, tissue engineering scaffolds, and antimicrobial agents. The distinctive physicochemical properties of DESs, including low toxicity, low volatility, and adaptable solvation power, enable the customization of chitin and chitosan-based materials to meet specific pharmaceutical requirements. Moreover, the environmentally friendly nature of DESs aligns with the growing demand for sustainable and eco-friendly processes in pharmaceutical manufacturing. This revision underscores recent advances illustrating the promising role of DESs in evolving the pharmaceutical applications of chitin and chitosan, laying the groundwork for the development of innovative drug delivery systems and biomedical materials with enhanced efficacy and safety profiles. Full article
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11 pages, 1842 KiB  
Article
CO2 Oxidative Dehydrogenation of Propane to Olefin over Cr-M (M = Zr, La, Fe) Based Zeolite Catalyst
by Mingqiao Xing, Ning Liu, Chengna Dai and Biaohua Chen
Catalysts 2024, 14(6), 370; https://doi.org/10.3390/catal14060370 - 7 Jun 2024
Viewed by 336
Abstract
CO2 oxidative dehydrogenation of propane (CO2-ODHP), being not only favorable for olefin production but also beneficial for CO2 emission control, has recently attracted great attention. Here, a series of single metal (Cr) and bimetal (Zr, La, Fe) modified ZSM-5 [...] Read more.
CO2 oxidative dehydrogenation of propane (CO2-ODHP), being not only favorable for olefin production but also beneficial for CO2 emission control, has recently attracted great attention. Here, a series of single metal (Cr) and bimetal (Zr, La, Fe) modified ZSM-5 zeolites were prepared via an impregnation method. It was found that the bimetal modified ZSM-5 possessed much higher C3H8 and CO2 conversion than that of monometallic modified Cr3%-ZSM-5 (Cr3%-Z5), especially for Cr3%Zr2%-ZSM-5 (Cr3%Zr2%-Z5), which displayed the highest activity (65.4%) and olefin yield (1.65 × 103 μmol·gcat1 h−1). Various characterizations were performed, including XRD, N2 adsorption-desorption, H2-TPR, Raman, XPS, HAAD-STEM, and TEM. It was revealed that Zr not only favored an improvement in the redox ability of Cr, but also contributed to the surface dispersion of loaded Cr species, constituting two major reasons explaining the superior activity of Cr3%Zr2%-Z5. To further improve CO2-ODHP catalytic behavior, a series of Cr3%-ZSM-5@SBA-15-n composite zeolite catalysts with diverse (ZSM-5/SBA-15) mass ratios were prepared (Cr3%-ZS-n, n = 0.5, 2, 6, 16), which screened out an optimum mass ratio of six. Based on this, the Cr3%Zr2%-ZS-6 compound was further prepared, and it eventually achieved even higher CO2-ODHP activity (76.9%) and olefin yield (1.72 × 103 μmol·gcat1 h−1). Finally, the CO2-ODHP reaction mechanism was further investigated using in situ FTIR, and it was found that the reaction followed the Mars–van Krevelen mechanism, wherein CO2 participated in the reaction through generation of polydentate carbonates. The Cr6+ constituted as the active site, which was reduced to Cr3+ after the dihydrogen reaction, and was then further oxidized into Cr6+ by CO2, forming polydentate carbonates, and thus cycling the reactive species Cr6+. Additionally, assisted by a Brönsted acid site (favoring breaking of the C-C bond), C2H4 and CH4 were produced. Full article
(This article belongs to the Special Issue Zeolites and Zeolite-Based Catalysis)
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14 pages, 10965 KiB  
Article
Green Synthesis of Manganese-Cobalt Oxyhydroxide Nanocomposite as Electrocatalyst for Enhanced Oxygen Evolution Reaction in Alkaline Medium
by Rajeh Alotaibi, Mabrook S. Amer, Prabhakarn Arunachalam and Saad G. Alshammari
Catalysts 2024, 14(6), 369; https://doi.org/10.3390/catal14060369 - 6 Jun 2024
Viewed by 371
Abstract
Using green synthetic methods, a manganese-cobalt oxyhydroxide (MnCo-OOH) nanocomposite for electrocatalysis was prepared. Electrocatalysts were examined using powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), and field-emission scanning electron microscopy (FESEM). In an alkaline medium, cyclic voltammetry and chronoamperometric analysis were [...] Read more.
Using green synthetic methods, a manganese-cobalt oxyhydroxide (MnCo-OOH) nanocomposite for electrocatalysis was prepared. Electrocatalysts were examined using powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), and field-emission scanning electron microscopy (FESEM). In an alkaline medium, cyclic voltammetry and chronoamperometric analysis were applied to assess the electrocatalytic features of the MnCo-OOH nanocomposite. A strong correlation existed between MnCo-OOH’s morphology, crystallinity, and electrochemical activity. Upon examining the electrochemical characteristics, the as-deposited MnCo-OOH catalyst demonstrated a significantly lower overpotential, achieving 75 mA·cm−2 OER current density at 370 mV, four times larger than 19.7 mA·cm−2 for CoOOH catalysts, signifying that the MnCo-OOH catalyst exhibits a higher electrocatalytic OER features. In addition, the MnCo-OOH nanocomposite demonstrated a high current density of 30 and 65 mA·cm−2 at 1.55 and 1.60 VRHE for 12 h in 1.0 M KOH aqueous electrolyte. As a result of this study, it was determined that the fabricated MnCo-OOH nanocomposite would be an appropriate electrocatalyst in water electrolysis. Full article
(This article belongs to the Section Electrocatalysis)
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28 pages, 9287 KiB  
Review
Recent Advances in Vanadium-Based Electrocatalysts for Hydrogen and Oxygen Evolution Reactions: A Review
by Haoyu Li, Juan Wu, Mengyao Li and Yude Wang
Catalysts 2024, 14(6), 368; https://doi.org/10.3390/catal14060368 - 5 Jun 2024
Viewed by 316
Abstract
With the intensification of global resource shortages and the environmental crisis, hydrogen energy has garnered significant attention as a renewable and clean energy source. Water splitting is considered the most promising method of hydrogen production due to its non-polluting nature and high hydrogen [...] Read more.
With the intensification of global resource shortages and the environmental crisis, hydrogen energy has garnered significant attention as a renewable and clean energy source. Water splitting is considered the most promising method of hydrogen production due to its non-polluting nature and high hydrogen concentration. However, the slow kinetics of the two key reactions, the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER), have greatly limited the development of related technologies. Meanwhile, the scarcity and high cost of precious metal catalysts represented by Pt and Ir/RuO2 limit their large-scale commercial application. Thus, it is essential to develop catalysts based on Earth’s transition metals that have abundant reserves. Vanadium (V) is an early transition metal with a distinct electronic structure from late transition metals such as Fe, Co, and Ni, which has been emphasized and studied by researchers. Numerous vanadium-based electrocatalysts have been developed for the HER and OER. In this review, the mechanisms of the HER and OER are described. Then, the compositions, properties, and modification strategies of various vanadium-based electrocatalysts are summarized, which include vanadium-based oxides, hydroxides, dichalcogenides, phosphides, nitrides, carbides, and vanadate. Finally, potential challenges and future perspectives are presented based on the current status of V-based electrocatalysts for water splitting. Full article
12 pages, 17335 KiB  
Article
Acetylacetone Boosts the Photocatalytic Activity of Metal–Organic Frameworks by Tunable Modification
by Kunrui Wei, Jianghua Yang, Shuangshuang Wei, Hongcen Zheng and Shujuan Zhang
Catalysts 2024, 14(6), 367; https://doi.org/10.3390/catal14060367 - 5 Jun 2024
Viewed by 303
Abstract
Typical metal–organic frameworks (MOFs) usually suffer from a limited visible light-trapping ability and easy recombination of charge carriers, hindering their photocatalytic applications. Acetylacetone (AA), leveraging its exceptional coordination capabilities, serves as a versatile and effective modifier for enhancing the photocatalytic activity of MOFs [...] Read more.
Typical metal–organic frameworks (MOFs) usually suffer from a limited visible light-trapping ability and easy recombination of charge carriers, hindering their photocatalytic applications. Acetylacetone (AA), leveraging its exceptional coordination capabilities, serves as a versatile and effective modifier for enhancing the photocatalytic activity of MOFs via a post-synthesis approach. The synthesis of diketone-anchored MOFs with AA can be achieved by first diazotizing the amino groups on the ligands of MOFs, followed by a condensation reaction between AA and the resulting azide. Gradient AA loadings ranging from 17% to 98% were obtained, showcasing the tunability of this approach. Interestingly, a sub-stoichiometric effect was exhibited between the AA loading and the visible photocatalytic performance of the modified photocatalyst. The singlet oxygen yields of MIL-125-AA-37% and MIL-125-AA-54% were about 1.3 times that of MIL-125-AA-17% and 3.0 times that of MIL-125-AA-98%. The improved photocatalytic activity could be attributed to the fact that the AA modification altered the electron density of the Ti metal center, leading to the creation of a significant amount of oxygen defects. This alteration resulted in a reduction in the recombination of charge carriers and thus a better charge separation. In short, AA modification provides a new strategy to maximize the visible photocatalytic performance of MOFs. Full article
(This article belongs to the Special Issue Exclusive Papers in Green Photocatalysis from China)
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27 pages, 7936 KiB  
Review
TiO2-Based Catalysts with Various Structures for Photocatalytic Application: A Review
by Cheng Song, Lanqing Xiao, Yan Chen, Fan Yang, Huiying Meng, Wanying Zhang, Yifan Zhang and Yang Wu
Catalysts 2024, 14(6), 366; https://doi.org/10.3390/catal14060366 - 4 Jun 2024
Viewed by 288
Abstract
TiO2-based catalysts with various surface heterostructures (0D, 1D, 2D, and 3D) have been widely researched owing to their cost-effectiveness, high stability, and environmentally friendly nature, and can be used for many applications in various fields, including hydrogen production and pollutant degradation. However, there [...] Read more.
TiO2-based catalysts with various surface heterostructures (0D, 1D, 2D, and 3D) have been widely researched owing to their cost-effectiveness, high stability, and environmentally friendly nature, and can be used for many applications in various fields, including hydrogen production and pollutant degradation. However, there are also many existing problems limiting their practical application, such as their large band gap and rapid electron–hole recombination rate. Owing to the abundance of recent achievements in materials science, we will summarize the recent structural engineering strategies which provide favorable photocatalytic activity enhancements, such as enhanced visible light absorption, stability, an increased charge–carrier separation rate and improved specific surface area. Among the various structural engineering methods in this review, we will introduce TiO2-based materials with different dimensional structures. Meanwhile, we also discuss recent achievements in synthesis methods and application of TiO2-based catalysts in various fields. We aim to display a comprehensive overview which can be a guide for the development of a new generation of TiO2-based catalysts according to their structural design for enhanced solar energy conversion. Full article
(This article belongs to the Section Catalytic Materials)
16 pages, 4774 KiB  
Article
Pt3Mn/SiO2 + ZSM-5 Bifunctional Catalyst for Ethane Dehydroaromatization
by Shan Jiang, Che-Wei Chang, William A. Swann, Christina W. Li and Jeffrey T. Miller
Catalysts 2024, 14(6), 365; https://doi.org/10.3390/catal14060365 - 4 Jun 2024
Viewed by 384
Abstract
Ethane dehydroaromatization (EDA) is a potentially attractive process for converting ethane to valuable aromatics such as benzene, toluene, and xylene (BTX). In this study, a Pt3Mn/SiO2 + ZSM-5 bifunctional catalyst was used to investigate the effect of dehydrogenation and the [...] Read more.
Ethane dehydroaromatization (EDA) is a potentially attractive process for converting ethane to valuable aromatics such as benzene, toluene, and xylene (BTX). In this study, a Pt3Mn/SiO2 + ZSM-5 bifunctional catalyst was used to investigate the effect of dehydrogenation and the Brønsted acid catalyst ratio, hydrogen partial pressure, and reaction temperature on the product distributions for EDA. Pt3Mn/SiO2 + ZSM-5 with a 1/1 weight ratio showed the highest ethane conversion rate and BTX formation rate. Ethylene is initially formed by dehydrogenation by the Pt3Mn catalyst, which undergoes secondary reactions on ZSM-5, forming C3+ reaction intermediates. The latter form final products of CH4 and BTX. At conversions from 15 to 30%, the BTX selectivities are 82–90%. For all bifunctional catalysts, the ethane conversion significantly exceeds the ethane–ethylene equilibrium conversion due to reaction to secondary products. Low H2 partial pressures did not significantly alter the product selectivity or conversion. However, higher H2 partial pressures resulted in increased methane and decreased BTX selectivity. The excess hydrogen saturated the olefin intermediates to form alkanes, which produced methane by monomolecular cracking on ZSM-5. With an increasing reaction temperature from 550 °C to 650 °C, the benzene selectivity increased, while the highest BTX selectivity was obtained at 600 to 650 °C. Full article
(This article belongs to the Special Issue Research Advances in Zeolites and Zeolite-Based Catalysts)
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15 pages, 3921 KiB  
Article
Modification of NiSe2 Nanoparticles by ZIF-8-Derived NC for Boosting H2O2 Production from Electrochemical Oxygen Reduction in Acidic Media
by Qiaoting Cheng, Hu Ding, Lang Chen, Jiatong Dong, Hao Yu, Shen Yan and Hua Wang
Catalysts 2024, 14(6), 364; https://doi.org/10.3390/catal14060364 - 3 Jun 2024
Viewed by 179
Abstract
The two-electron oxygen reduction reaction (2e ORR) has emerged as an attractive alternative for H2O2 production. Developing efficient earth-abundant transition metal electrocatalysts and reaction mechanism exploration for H2O2 production are important but remain challenging. Herein, a [...] Read more.
The two-electron oxygen reduction reaction (2e ORR) has emerged as an attractive alternative for H2O2 production. Developing efficient earth-abundant transition metal electrocatalysts and reaction mechanism exploration for H2O2 production are important but remain challenging. Herein, a nitrogen-doped carbon-coated NiSe2 (NiSe2@NC) electrocatalyst was prepared by successive annealing treatment. Benefiting from the synergistic effect between the NiSe2 nanoparticles and NC, the 2e ORR activity, selectivity, and stability of NiSe2@NC in 0.1 M HClO4 was greatly enhanced, with the yield of H2O2 being 4.4 times that of the bare NiSe2 nanoparticles. The in situ Raman spectra and density functional theory (DFT) calculation revealed that the presence of NC was beneficial for regulating the electronic state of NiSe2 and optimizing the adsorption free energy of *OOH, which could enhance the adsorption of O2, stabilize the O-O bond, and boost the production of H2O2. This work provides an effective strategy to improve the performance of the transition metal chalcogenide for 2e ORR to H2O2. Full article
(This article belongs to the Special Issue Electrocatalysis for Hydrogen/Oxygen Evolution Reactions)
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15 pages, 1994 KiB  
Review
Non-Oxidative Coupling of Methane Catalyzed by Heterogeneous Catalysts Containing Singly Dispersed Metal Sites
by Yuting Li and Jie Zhang
Catalysts 2024, 14(6), 363; https://doi.org/10.3390/catal14060363 - 2 Jun 2024
Viewed by 351
Abstract
Direct upgrading of methane into value-added products is one of the most significant technologies for the effective transformation of hydrocarbon feedstocks in the chemical industry. Both oxidative and non-oxidative methane conversion are broadly useful approaches, though the two reaction pathways are quite distinguished. [...] Read more.
Direct upgrading of methane into value-added products is one of the most significant technologies for the effective transformation of hydrocarbon feedstocks in the chemical industry. Both oxidative and non-oxidative methane conversion are broadly useful approaches, though the two reaction pathways are quite distinguished. Oxidative coupling of methane (OCM) has been widely studied, but suffers from the low selectivity to C2 hydrocarbons because of the overoxidation leading to undesired byproducts. Therefore, non-oxidative coupling of methane is a worthy alternative approach to be developed for the efficient, direct utilization of methane. Recently, heterogeneous catalysts comprising singly dispersed metal sites, such as single-atom catalysts (SAC) and surface organometallic catalysts (SOMCat), have been proven to be effectively active for direct coupling of methane to product hydrogen and C2 products. In this context, this review summarizes recent discoveries of these novel catalysts and provides a perspective on promising catalytic processes for methane transformation via non-oxidative coupling. Full article
(This article belongs to the Special Issue Study of Novel Catalysts for Methane Conversion)
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16 pages, 7133 KiB  
Article
Investigation and Comparison of Catalytic Methods to Produce Green CO2-Containing Monomers for Polycarbonates
by Daniel Christian Brüggemann, Philipp Harry Isbrücker, Dzenna Zukova, Franz Robert Otto Heinrich Schröter, Yen Hoang Le and Reinhard Schomäcker
Catalysts 2024, 14(6), 362; https://doi.org/10.3390/catal14060362 - 1 Jun 2024
Viewed by 261
Abstract
The preparation of CO2-containing polymers with improved degradation properties is still very challenging. An elegant method for preparing these polymers is to use CO2-containing monomers in ring-opening polymerizations (ROP) which are particularly gentle and energy-saving methods. However, cyclic carbonates [...] Read more.
The preparation of CO2-containing polymers with improved degradation properties is still very challenging. An elegant method for preparing these polymers is to use CO2-containing monomers in ring-opening polymerizations (ROP) which are particularly gentle and energy-saving methods. However, cyclic carbonates are required for this which are not readily available. This paper therefore aims to present the optimization and comparison of two synthesis methods to obtain cyclic carbonates for ROP. Within this work, cyclic styrene carbonate was synthesized from readily available raw materials by using a Jacobsen catalyst for the reaction of styrene oxide and carbon dioxide or an organocatalyst for the transesterification of methyl carbonate with 1-phenyl-1,2-ethanediol. The latter performed with 100% selectivity to the desired styrene carbonate, which was succesfully tested in ROP, producing an amorphous thermoplastic polymer with a TG of 185 C. Full article
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12 pages, 4842 KiB  
Article
Cu-MOF-74-Derived CuO-400 Material for CO2 Electroreduction
by Hua Liu, Ya-Li Wang, Lei-Bing Chen, Meng-Han Li, Jia-Xing Lu and Huan Wang
Catalysts 2024, 14(6), 361; https://doi.org/10.3390/catal14060361 - 31 May 2024
Viewed by 218
Abstract
This study proposes a straightforward strategy utilizing metal–organic frameworks (MOFs) to obtain efficient electrocatalysts for synthesizing C2 products (C2H4 and C2H5OH) via a CO2 reduction reaction. Cu-MOF-74 was chosen as the precursor, while copper oxide [...] Read more.
This study proposes a straightforward strategy utilizing metal–organic frameworks (MOFs) to obtain efficient electrocatalysts for synthesizing C2 products (C2H4 and C2H5OH) via a CO2 reduction reaction. Cu-MOF-74 was chosen as the precursor, while copper oxide nanoparticles were obtained through a calcination method. During the calcination process, by controlling the calcination conditions, the porous structure of the MOF framework was successfully retained, leading to CuO-400 with a high catalytic activity and C2 production efficiency. Compared to CuO-n formed by the calcination of Cu(NO3)2, CuO-400 derived from MOFs exhibits a 1.6 times higher C2 activity as an electrocatalytic material at −1.15 V vs. RHE. Full article
(This article belongs to the Special Issue New Insights into Electrocatalysis for Energy Storage and Conversion)
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18 pages, 4492 KiB  
Article
Design of Experiments for Process Optimization of the Direct Wacker-Type Oxidation of 1-Decene to n-Decanal
by Thomas Bouveyron, Patricia Bratenberg, Peter Bell and Matthias Eisenacher
Catalysts 2024, 14(6), 360; https://doi.org/10.3390/catal14060360 - 31 May 2024
Viewed by 243
Abstract
The rapid increase in the use and development of statistical design of experiments (DoE), particularly in pharmaceutical process development, has become increasingly important over the last decades. This rise aligns with Green Chemistry Principles, seeking reduced resource usage and heightened efficiency. In this [...] Read more.
The rapid increase in the use and development of statistical design of experiments (DoE), particularly in pharmaceutical process development, has become increasingly important over the last decades. This rise aligns with Green Chemistry Principles, seeking reduced resource usage and heightened efficiency. In this study, we employed a comprehensive design of experiments (DoE) approach to optimize the catalytic conversion of 1-decene to n-decanal through direct Wacker-type oxidation using the previously determined efficient PdCl2(MeCN)2 catalytic system. The aim was to maximize selectivity and conversion efficiency. Through systematic variation of seven factors, including substrate amount, catalyst and co-catalyst amount, reaction temperature, reaction time, homogenization temperature, and water content, this study identified critical parameters influencing the process to direct the reaction toward the desired product. The statistical analysis revealed high significance for both selectivity and conversion, with surface diagrams illustrating optimal conditions. Notably, catalyst amount emerged as a pivotal factor influencing conversion, with reaction temperature and co-catalyst amount significantly affecting both conversion efficiency and selectivity. The refined model demonstrated strong correlations between predicted and observed values, highlighting the impact of these factors on both selectivity and conversion. Full article
(This article belongs to the Special Issue Catalysis for Functionalization Reaction of Hydrocarbons Compounds)
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17 pages, 3023 KiB  
Article
Effect of the Metal of a Metallic Ionic Liquid (-butyl-methylimidazolium tetrachloroferrate) on the Oxidation of Hydrazine
by Marcela Brockmann, Freddy Navarro, José Ibarra, Constanza León, Francisco Armijo, María Jesús Aguirre, Galo Ramírez and Roxana Arce
Catalysts 2024, 14(6), 359; https://doi.org/10.3390/catal14060359 - 31 May 2024
Viewed by 216
Abstract
This work investigates the electrocatalytic properties of carbon paste electrodes (CPEs) modified with ionic liquids (IL) and metallic ionic liquid (ILFe) for the hydrazine oxidation reaction (HzOR). The results indicate that ILFe significantly enhances the catalytic activity of the electrode, exhibiting catalysis towards [...] Read more.
This work investigates the electrocatalytic properties of carbon paste electrodes (CPEs) modified with ionic liquids (IL) and metallic ionic liquid (ILFe) for the hydrazine oxidation reaction (HzOR). The results indicate that ILFe significantly enhances the catalytic activity of the electrode, exhibiting catalysis towards hydrazine oxidation, reducing overpotential, and increasing reaction current. It is determined that the HzOR on the MWCNT/MO/ILFe electrode involves the transfer of four electrons, with high selectivity for nitrogen formation. Additionally, ILFe is observed to improve the wettability of the electrode surface, increasing its capacitance and reaction efficiency. This study highlights the advantages of ILFe-modified CPEs in terms of simplicity, cost-effectiveness, and improved performance for electrochemical applications, demonstrating how the ionic liquid catalyzes hydrazine oxidation despite its lower conductivity. Full article
(This article belongs to the Section Catalytic Materials)
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12 pages, 1724 KiB  
Article
Regulating the Monomer Symmetry of Poly-Perylene-Diimides for Photocatalytic H2O2 Production
by Meiwanqin Zhou, Yukun Yan, Jinsong Zhang and Jun Xiao
Catalysts 2024, 14(6), 358; https://doi.org/10.3390/catal14060358 - 31 May 2024
Viewed by 219
Abstract
Photocatalysis technology is an economical and effective new energy technology which depends on the conversion and storage of light energy through an energy transfer process or charge transfer process. Recently, organic semiconductor photocatalytic materials with the advantages of controllable structure, broad spectral response, [...] Read more.
Photocatalysis technology is an economical and effective new energy technology which depends on the conversion and storage of light energy through an energy transfer process or charge transfer process. Recently, organic semiconductor photocatalytic materials with the advantages of controllable structure, broad spectral response, designability, and flexibility have received wide attention. In particular, the organic polymeric materials containing poly-perylene diimides (PDI) show significant promise in the realm of photocatalysis due to their impressive catalytic capabilities and wide spectral reactivity. However, a poor charge separation and transportation (CST) process undermines their photocatalytic efficiency in most polymer photocatalysts, as well as in PDI photocatalysts. In this context, we propose a new strategy through regulating the monomer symmetry to construct highly efficient PDI photocatalysts. As proof-of-concept, a series of new PDI-based organic supramolecular photocatalytic materials with full visible spectral response from the perspectives of both the π-π conjugated structure and the symmetry of chain structure are successfully synthesized. Meanwhile, the structural compositions, morphology features, electrical properties, and photocatalytic performances of those obtained PDI photocatalysts were systematically studied. The results shown that the as-prepared PDI-1,5NDA exhibits 1.6-fold and 3.7-fold higher levels of photosynthesis of H2O2 activity than those of PDI-1,4NDA and PDI-PDA, respectively, which could be ascribe to its lower symmetry and large π-conjugate systems greatly enhances the separation of charge carriers. Full article
(This article belongs to the Section Photocatalysis)
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14 pages, 4457 KiB  
Article
TiO2/p-BC Composite Photocatalyst for Efficient Removal of Tetracycline from Aqueous Solutions under Simulated Sunlight
by Jianhui Liu, Liwen Zheng, Yongchao Gao, Lei Ji, Zhongfeng Yang, Hailun Wang, Ming Shang, Jianhua Du and Xiaodong Yang
Catalysts 2024, 14(6), 357; https://doi.org/10.3390/catal14060357 - 31 May 2024
Viewed by 161
Abstract
Pollution caused by antibiotics has brought significant challenges to the ecological environment. To improve the efficiency of the removal of tetracycline (TC) from aqueous solutions, a composite material consisting of TiO2 and phosphoric acid-treated peanut shell biochar (p-BC) has been successfully synthesized [...] Read more.
Pollution caused by antibiotics has brought significant challenges to the ecological environment. To improve the efficiency of the removal of tetracycline (TC) from aqueous solutions, a composite material consisting of TiO2 and phosphoric acid-treated peanut shell biochar (p-BC) has been successfully synthesized in the present study by the sol-gel method. In addition, the composite material was characterized using various techniques, including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and ultraviolet–visible diffuse reflectance spectroscopy (UV-vis DRS). The XPS and FTIR analyses revealed the formation of a new Ti–O–C bond, while the XRD analysis confirmed the presence of TiO2 (with an anatase phase) in the composite material. Also, the PL analyses showed a notable decrease in the recombination efficiency of electrons and holes, which was due to the formation of a composite. This was further supported by the UV-vis DRS analyses, which revealed a decrease in bandgap (to 2.73 eV) of the composite material and led to enhanced light utilization and improved photocatalytic activity. Furthermore, the effects of pH, composite dosage, and initial concentration on the removal of TC were thoroughly examined, which resulted in a maximum removal efficiency of 95.3% under optimal conditions. Additionally, five consecutive cycle tests demonstrated an exceptional reusability and stability of the composite material. As a result of the experiments, the active species verified that ·O2 played a key role in the photodegradation of TC. Four possible degradation pathways of TC were then proposed. As a general conclusion, the TiO2/p–BC composite can be used as an efficient photocatalyst in the removal of TC from aqueous solutions. Full article
(This article belongs to the Special Issue Recent Advances in Photocatalytic Treatment of Pollutants in Water)
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15 pages, 8884 KiB  
Article
Rational Design of Z-Scheme Heterostructures Composed of Bi/Fe-Based MOFs for the Efficient Photocatalytic Degradation of Organic Pollutants
by Jing Xu, Songlin Zhu, Huizhi Zhou, Minghao Hou, Kangle Wan, Xueqi Zhang, Wei Yan, Yingcong Wei and Yuanping Chen
Catalysts 2024, 14(6), 356; https://doi.org/10.3390/catal14060356 - 30 May 2024
Viewed by 229
Abstract
Metal–organic frameworks (MOFs) have recently gained attention as a highly promising category of photocatalytic materials, showing great potential in the degradation of organic dyes such as Rhodamine B (RhB). Nonetheless, the mono-metal MOF materials in this application are often constrained by their limited [...] Read more.
Metal–organic frameworks (MOFs) have recently gained attention as a highly promising category of photocatalytic materials, showing great potential in the degradation of organic dyes such as Rhodamine B (RhB). Nonetheless, the mono-metal MOF materials in this application are often constrained by their limited light absorption capabilities and their propensity for recombination with carriers. The combination of different metal-based MOFs to form heterogeneous reactors could present a promising approach for the removal of dyes from water. In this work, a new CAU-17/MIL-100(Fe) Z-scheme heterojunction photocatalyst composed of two MOFs with the same ligands is reported to realize the efficient degradation of dyes in water. The combination of the two MOFs results in a significant enhancement of the surface open sites, optical responsivity range, and charge-separating efficiency through synergistic effects. In addition, the capture experiments conducted on the photocatalytic process have verified that ∙O2 and h+ are the primary active species. Consequently, CAU-17/MIL-100(Fe) exhibited excellent photocatalytic activity and stability. The degradation rate of the optimal CAU-17/MIL-100(Fe) photocatalyst was 34.55 times that of CAU-17 and 3.60 times that of MIL-100(Fe). Our work provides a new strategy for exploring the visible-light degradation of RhB in bimetallic MOF composites. Full article
(This article belongs to the Section Photocatalysis)
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20 pages, 3750 KiB  
Review
Performance of Ni-Based Catalysts with La Promoter for the Reforming of Methane in Gasification Process
by Meng Chen and Lei Wang
Catalysts 2024, 14(6), 355; https://doi.org/10.3390/catal14060355 - 30 May 2024
Viewed by 199
Abstract
The deactivation of active sites caused by high-temperature sintering and the deposition of a large amount of carbon are the main difficulties in the reforming of methane using Ni-based catalysts. La, as a promoter, has an ameliorating effect on the defects of Ni-based [...] Read more.
The deactivation of active sites caused by high-temperature sintering and the deposition of a large amount of carbon are the main difficulties in the reforming of methane using Ni-based catalysts. La, as a promoter, has an ameliorating effect on the defects of Ni-based catalysts. In this article, the mechanism of action of Ni-based catalysts with the introduction of the rare-earth metal additive La was reviewed, and the effects of La on the methane-reforming performance of Ni-based catalysts were examined. The physical properties, alkalinity, and activity of Ni-based catalysts can be enhanced by the use of the auxiliary agent La, which promotes the conversion of CH4 and CO2 as well as the selectivity towards H2 and CO formation in the reforming of methane. The reason why the Ni-based catalysts could maintain long-term stability in the presence of La was discussed. Furthermore, the current state of research on the introduction of different amounts of La in the reforming of methane at home and abroad was analyzed. It was found that 2–5 wt.% La is the most optimal quantity for improving the catalyst activity and stability, as well as the CO2 chemisorption. The limitations and directions for future research in the reforming of methane were discussed. Full article
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20 pages, 4207 KiB  
Article
Nano-Magnetic Sugarcane Bagasse Cellulosic Composite as a Sustainable Photocatalyst for Textile Industrial Effluent Remediation
by Maha A. Tony, Nour Sh. El-Gendy, Mohamed Hussien, Abdullah A. S. Ahmed, Jiayu Xin, Xingmei Lu and Ibrahim El Tantawy El-Sayed
Catalysts 2024, 14(6), 354; https://doi.org/10.3390/catal14060354 - 30 May 2024
Viewed by 238
Abstract
Researchers have focused on deriving environmentally benign materials from biomass waste and converting them into value-added materials. In this study, cellulosic crystals derived from sugarcane bagasse (SCB) are augmented with magnetite (M) nanoparticles. Following the co-precipitation route, the composite was prepared, and then [...] Read more.
Researchers have focused on deriving environmentally benign materials from biomass waste and converting them into value-added materials. In this study, cellulosic crystals derived from sugarcane bagasse (SCB) are augmented with magnetite (M) nanoparticles. Following the co-precipitation route, the composite was prepared, and then the mixture was subjected to a green microwave solvent-less technique. Various mass ratios of SCB:M (1:1, 2:1, 3:1, 5:1, and 1:2) were prepared and efficiently utilized as photocatalysts. To look at the structural and morphological properties of the prepared samples, X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), and elemental analysis were used to describe the composite fibers. SCB:M augmented with H2O2 as a Fenton reaction was used to eliminate Reactive blue 19 (RB19) from polluted water and was compared with pristine SCB and M. Additionally, the response surface methodology (RSM) statistically located and assessed the optimized parameters. The optimal operating conditions were recorded at pH 2.0 and 3:1 SCB: M with 40 mg/L and 100 mg/L of hydrogen peroxide. However, the temperature increase inhibits the oxidation reaction. The kinetic modeling fit showed the reaction following the second-order kinetic model with an energy barrier of 98.66 kJ/mol. The results show that such photocatalyst behavior is a promising candidate for treating textile effluent in practical applications. Full article
(This article belongs to the Section Photocatalysis)
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13 pages, 3586 KiB  
Article
Water-Soluble Fe(III) Complex Catalyzed Coupling Aquathermolysis of Water-Heavy Oil-Methanol
by Shijun Chen, Shu Zhang, Jinchao Feng, Xiaolong Long, Tianbao Hu and Gang Chen
Catalysts 2024, 14(6), 353; https://doi.org/10.3390/catal14060353 - 30 May 2024
Viewed by 157
Abstract
In this experimental study, diverse water-soluble Fe(III) complexes were synthesized and employed to catalyze the aquathermolysis of heavy oil. A ternary reaction system comprising heavy oil, water, and methanol was established to facilitate the process. Viscometry, thermogravimetric analysis, DSC, and elemental analysis were [...] Read more.
In this experimental study, diverse water-soluble Fe(III) complexes were synthesized and employed to catalyze the aquathermolysis of heavy oil. A ternary reaction system comprising heavy oil, water, and methanol was established to facilitate the process. Viscometry, thermogravimetric analysis, DSC, and elemental analysis were utilized to thoroughly investigate the treated heavy oil. The findings reveal that, under optimal conditions of water, catalyst, and methanol dosage, the viscosity of heavy oil can be significantly reduced by up to 88.22% after reacting at 250 °C for 12 h. Notably, apart from viscosity reduction, the catalytic aquathermolysis also effectively removes heteroatoms such as sulfur, nitrogen, and oxygen, enabling in situ modification and viscosity reduction of heavy oil. This study demonstrates the potential of water-soluble Fe(III) complexes in enhancing the efficiency of heavy oil extraction and processing. Full article
(This article belongs to the Section Industrial Catalysis)
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