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Keywords = catalytic transfer hydrogenation

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17 pages, 2215 KiB  
Article
Hydrocracking of Polyethylene to Gasoline-Range Hydrocarbons over a Ruthenium-Zeolite Bifunctional Catalyst System with Optimal Synergy of Metal and Acid Sites
by Qing Du, Xin Shang, Yangyang Yuan, Xiong Su and Yanqiang Huang
Catalysts 2025, 15(4), 335; https://doi.org/10.3390/catal15040335 (registering DOI) - 31 Mar 2025
Viewed by 32
Abstract
Chemical recycling of plastic waste, especially polyolefins, into valuable liquid fuels is of considerable significance to address the serious issues raised by their threat on environmental and human health. Nevertheless, the construction of efficient and economically viable catalytic systems remains a significant hurdle. [...] Read more.
Chemical recycling of plastic waste, especially polyolefins, into valuable liquid fuels is of considerable significance to address the serious issues raised by their threat on environmental and human health. Nevertheless, the construction of efficient and economically viable catalytic systems remains a significant hurdle. Herein, we developed an efficient bifunctional catalyst system comprising γ-Al2O3-supported ruthenium nanoparticles (Ru/γ-Al2O3) and β-zeolite for the conversion of polyolefins into gasoline-range hydrocarbons. A yield of C5–12 paraffins up to 73.4% can be obtained with polyethene as the reactant at 250 °C in hydrogen. The Ru sites primarily activate the initial cleavage of C–H bonds of polymer towards the formation of olefin intermediates, which subsequently go through further cracking and isomerization over the acid sites in β-zeolite. Employing in situ infrared spectroscopy and probe–molecule model reactions, our investigation reveals that the optimized proportion and spatial distribution of the dual catalytic sites are pivotal in the tandem conversion process. This optimization synergistically regulates the cracking kinetics and accelerates intermediate transfer, thereby minimizing the production of side C1–4 hydrocarbons resulting from over-cracking at the Ru sites and enhancing the yield of liquid fuels. This research contributes novel insights into catalyst design for the chemical upgrading of polyolefins into valuable chemicals, advancing the field of plastic waste recycling and sustainable chemical production. Full article
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14 pages, 3454 KiB  
Article
Synthesis of Star Isotactic Polypropylene via Styryldichlorosilane/Hydrogen Consecutive Chain Transfer Reaction
by Naw Jar, Fengtao Chen and Jin-Yong Dong
Catalysts 2025, 15(4), 331; https://doi.org/10.3390/catal15040331 - 31 Mar 2025
Viewed by 20
Abstract
This paper elucidates the consecutive chain transfer reaction, initially to (p-vinylphenyl) methyl dichlorosilane (or (p-vinylbenzyl) methyl dichlorosilane), followed by hydrogen, during metallocene-catalyzed propylene polymerization by an isospecific metallocene catalyst (i.e., rac-dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride, I)/ activated with methylaluminoxane (MAO), rendering [...] Read more.
This paper elucidates the consecutive chain transfer reaction, initially to (p-vinylphenyl) methyl dichlorosilane (or (p-vinylbenzyl) methyl dichlorosilane), followed by hydrogen, during metallocene-catalyzed propylene polymerization by an isospecific metallocene catalyst (i.e., rac-dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride, I)/ activated with methylaluminoxane (MAO), rendering a catalytic access styryldichlorosilane capped isotactic polypropylenes (iPP). The PP molecular weight is inversely related to the molar ratio of [(p-vinylphenyl) methyl dichlorosilane]/[propylene] and [(p-vinylbenzyl) methyl dichlorosilane]/[propylene]. Every polypropylene chain formed presents a terminal (p-vinylphenyl) methyl dichlorosilane (or (p-vinylbenzyl) methyl dichlorosilane) unit. Hydrogen enhances the concentration of the starting arm polymer for the subsequent synthesis of the star polymer by increasing the incorporation of the chain terminal group. In order to create star polymers with isotactic polypropylene(iPP) as the arm and a siloxane cross-linking structure as the core, the terminal dichlorosilane iPP unit can work up (with water) to create cyclic siloxane oligomer interlinkages between iPP chains. Full article
(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)
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31 pages, 5746 KiB  
Review
Development of Electrochemical Water Splitting with Highly Active Nanostructured NiFe Layered Double Hydroxide Catalysts: A Comprehensive Review
by Aviraj M. Teli, Sagar M. Mane, Sonali A. Beknalkar, Rajneesh Kumar Mishra, Wookhee Jeon and Jae Cheol Shin
Catalysts 2025, 15(3), 293; https://doi.org/10.3390/catal15030293 - 20 Mar 2025
Viewed by 330
Abstract
Electrochemical water splitting is a feasible and effective method for attaining hydrogen, offering a mechanism for renewable energy solutions to combat the world’s energy crises due to the scarcity of fossil fuels. Evidently, the viability and stability of the electrocatalysts are fundamental to [...] Read more.
Electrochemical water splitting is a feasible and effective method for attaining hydrogen, offering a mechanism for renewable energy solutions to combat the world’s energy crises due to the scarcity of fossil fuels. Evidently, the viability and stability of the electrocatalysts are fundamental to the electrochemical water-splitting process. However, the net efficiency of this process is noticeably hindered by the kinetic drawbacks related to the OER. Hence, NiFe LDH has been widely used as a highly efficient OER and HER catalyst material due to its unique nanostructure, tunable composition, and favorable electronic structure. This review offers a systematic analysis of the latest progress in the fabrication of functional NiFe LDH catalysts and associated fabrication strategies, structure optimizations, and performance improvements. Special emphasis is given to understanding the role of nanostructure engineering in increasing active site accessibility, enhancing the effectiveness of subsequent electron transfer, and boosting the intrinsic catalytic activity for HER and OER. Moreover, we discuss the influence of doping, defects, and the formation of heterostructures with other materials on the OER and HER activities of NiFe LDHs. Additional accounts of basic structures and the OER and HER catalytic activities are provided, along with an enhanced theoretical understanding based on DFT studies on the NiFe LDH. Moreover, the limitations and potential developments of the work focus on the need for existing synthesis approaches, the stability of the NiFe LDH catalysts, and their insertion into working electrochemical processes. This review is a comprehensive analysis of the current state of research and developments in the use of NiFe LDH catalysts for the electrochemical water-splitting process to foster improved development of sustainable hydrogen sources in the future. Full article
(This article belongs to the Special Issue Nanostructured Materials for Electrocatalytic Applications)
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20 pages, 4522 KiB  
Article
Hierarchical Core-Shell Cu@Cu-Ni-Co Alloy Electrocatalyst for Efficient Hydrogen Evolution in Alkaline Media
by Hussein A. Younus, Maimouna Al Hinai, Mohammed Al Abri and Rashid Al-Hajri
Energies 2025, 18(6), 1515; https://doi.org/10.3390/en18061515 - 19 Mar 2025
Viewed by 263
Abstract
The development of advanced electrocatalysts plays a pivotal role in enhancing hydrogen production through water electrolysis. In this study, we employed a two-step electrodeposition method to fabricate a 3D porous Cu-Co-Ni alloy with superior catalytic properties and long-term stability for hydrogen evolution reaction [...] Read more.
The development of advanced electrocatalysts plays a pivotal role in enhancing hydrogen production through water electrolysis. In this study, we employed a two-step electrodeposition method to fabricate a 3D porous Cu-Co-Ni alloy with superior catalytic properties and long-term stability for hydrogen evolution reaction (HER). The resulting trimetallic alloy, Cu@Cu-Ni-Co, demonstrated significant improvements in structural integrity and catalytic performance. A comparative analysis of electrocatalysts, including Cu, Cu@Ni-Co, and Cu@Cu-Ni-Co, revealed that Cu@Cu-Ni-Co achieved the best results in alkaline media. Electrochemical tests conducted in 1.0 M NaOH showed that Cu@Cu-Ni-Co reached a current density of 10 mA cm−2 at a low overpotential of 125 mV, along with a low Tafel slope of 79.1 mV dec−1. The catalyst showed exceptional durability, retaining ~95% of its initial current density after 120 h of continuous operation at high current densities. Structural analysis confirmed that the enhanced catalytic performance arises from the synergistic interaction between Cu, Ni, and Co within the well-integrated trimetallic framework. This integration results in a large electrochemical active surface area (ECSA) of 380 cm2 and a low charge transfer resistance (15.76 Ω), facilitating efficient electron transfer and promoting superior HER activity. These findings position Cu@Cu-Ni-Co as a highly efficient and stable electrocatalyst for alkaline HER in alkaline conditions. Full article
(This article belongs to the Special Issue Renewable Fuels and Chemicals)
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17 pages, 2578 KiB  
Article
Sulfur-Doped CoFe/NF Catalysts for High-Efficiency Electrochemical Urea Oxidation and Hydrogen Production: Structure Optimization and Performance Enhancement
by Sirong Li, Lang Yao, Zhenlong Wang, Zhonghe Xu and Xuechun Xiao
Catalysts 2025, 15(3), 285; https://doi.org/10.3390/catal15030285 - 18 Mar 2025
Viewed by 315
Abstract
In this study, a sulfur-doped cobalt–iron catalyst (CoFeS/NF) was synthesized on a nickel foam (NF) substrate via a facile one-step electrodeposition method, and its performance in urea electrolysis for hydrogen production was systematically investigated. Sulfur doping induced significant morphology optimization, forming a highly [...] Read more.
In this study, a sulfur-doped cobalt–iron catalyst (CoFeS/NF) was synthesized on a nickel foam (NF) substrate via a facile one-step electrodeposition method, and its performance in urea electrolysis for hydrogen production was systematically investigated. Sulfur doping induced significant morphology optimization, forming a highly dispersed nanosheet structure, which enhanced the specific surface area increase by 1.9 times compared with the undoped sample, exposing abundant active sites. Meanwhile, the introduction of sulfur facilitated electron redistribution at the surface modulated the valence states of nickel and cobalt, promoted the formation of high-valence Ni3+/Co3+, optimized the adsorption energy of the reaction intermediates, and reduced the charge transfer resistance. Electrochemical evaluations revealed that CoFeS/NF achieves a current density of 10 mA cm−2 at a remarkably low potential of 1.18 V for the urea oxidation reaction (UOR), outperforming both the undoped catalyst (1.24 V) and commercial RuO2 (1.35 V). In addition, the catalyst also exhibited excellent catalytic activity and long-term stability in the total urea decomposition process, which was attributed to the amorphous structure and the synergistic enhancement of corrosion resistance by sulfur doping. This study provides a new idea for the application of sulfur doping strategy in the design of multifunctional electrocatalysts, which promotes the coupled development of urea wastewater treatment and efficient hydrogen production technology. Full article
(This article belongs to the Special Issue Design and Synthesis of Nanostructured Catalysts, 2nd Edition)
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18 pages, 5810 KiB  
Article
Electrochemical Reduction Performance and Mechanism of 2,2′,4,4′-Tetrabromodiphenyl Ether (BDE-47) with Pd/Metal Foam Electrodes
by Chenghao Liang, He Liu, Jiahao Liang, Xiaodong Du, Xueqin Tao and Guining Lu
Processes 2025, 13(3), 853; https://doi.org/10.3390/pr13030853 - 14 Mar 2025
Viewed by 229
Abstract
Polybrominated diphenyl ethers (PBDEs), a type of brominated flame retardant, are of global concern due to their environmental persistence, bioaccumulation, toxicity, and resistance to conventional remediation methods. In this study, the electrochemical reduction of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) with Pd/Metal foam electrodes (Ni, Cu, [...] Read more.
Polybrominated diphenyl ethers (PBDEs), a type of brominated flame retardant, are of global concern due to their environmental persistence, bioaccumulation, toxicity, and resistance to conventional remediation methods. In this study, the electrochemical reduction of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) with Pd/Metal foam electrodes (Ni, Cu, and Ag) was investigated. The effect of Pd loadings was explored, and the results show that Pd loading enhances the debromination performance, with 15.16%Pd/Ni foam exhibiting the best efficiency, followed by 9.37%Pd/Cu and 10.26%Pd/Ag. The degradation mechanisms for Pd/Ni and Pd/Ag are primarily hydrogen atom transfer, while for Pd/Cu, electron transfer dominates. Among the reduction products, Pd/Ni foam shows the highest debromination capability. The impact of electrolytes, current intensity, and bromination degrees of PBDEs was evaluated for 15.16%Pd/Ni. The results reveal that the presence of electrolytes inhibits BDE-47 degradation; the degradation rate of BDE-47 increases with current density, peaks at 4 mA, and decreases as current rises; and 15.16%Pd/Ni foam can effectively degrade PBDEs with varying bromination levels. Additionally, cycling tests show a decrease in efficiency from 94.3% (first cycle) to 56.58% (fourth cycle), attributed to Pd loss and structural damage. The findings offer valuable insights for developing efficient, sustainable catalytic materials for the electrochemical degradation of PBDEs and other persistent organic pollutants. Full article
(This article belongs to the Special Issue Advances in Remediation of Contaminated Sites: 2nd Edition)
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16 pages, 5403 KiB  
Article
Boosting Visible-Light-Driven Hydrogen Evolution Enabled by Iodine-Linked Magnetically Curved Graphene with Mobius-like Electronic Paths
by Liangjun Cai, Hongxia Liu and Xiaoxiao Yan
Molecules 2025, 30(6), 1302; https://doi.org/10.3390/molecules30061302 - 13 Mar 2025
Viewed by 150
Abstract
Materials with high electron transfer performance remain a key focus in photocatalytic research, as they can effectively promote the separation of photogenerated carriers and enhance the utilization efficiency of photogenerated electrons. To enhance the effective utilization of photogenerated electrons, the MSIG material was [...] Read more.
Materials with high electron transfer performance remain a key focus in photocatalytic research, as they can effectively promote the separation of photogenerated carriers and enhance the utilization efficiency of photogenerated electrons. To enhance the effective utilization of photogenerated electrons, the MSIG material was prepared by incorporating the iodine clusters and magnetic Fe3O4 into the as-synthesized crumpled graphene oxide (CGO) to construct Möbius-like electronic transmission pathways. The introduction of magnetic groups optimized the spin orientation of electrons, facilitating directional electron transport and thereby enhancing the photocatalytic efficiency of the material. Experimental results reveal that, in visible light-driven hydrogen production reactions, the eosin Y (EY)-sensitized Pt-Fe3O4-MSIG catalyst exhibits outstanding catalytic performance, with a hydrogen production rate of 1.48 mL/h, which is 15 times higher than that of the Pt-Fe3O4 catalyst. Photoelectrochemical analyses show a significant increase in the catalyst’s fluorescence lifetime, attributed to the Möbius strip-like electron transport channels within the material. Theoretical calculations further support this by demonstrating that the bandgap widening of the CGO reduces the recombination probability of photogenerated carriers, thereby improving their average lifetime. This study offers a novel approach for the design of visible-light-driven photocatalytic materials. Full article
(This article belongs to the Special Issue Recent Advances in Transition Metal Catalysis, 2nd Edition)
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12 pages, 4134 KiB  
Article
Phase-Controlled Synthesis of Ru Supported on Carbon Nitride and the Application in Photocatalytic H2 Evolution
by Xiaohu Sun, Xiangyang Cao, Ganghua Zhou, Tiaolong Lv, Jian Xu, Yubo Zhou, Zhigang Wang and Jianjian Yi
Materials 2025, 18(6), 1259; https://doi.org/10.3390/ma18061259 - 13 Mar 2025
Viewed by 269
Abstract
This work aims to explore the influence of crystal phase engineering on the photocatalytic hydrogen evolution activity of Ru/C3N4 systems. By precisely tuning the combination of Ru precursors and reducing solvents, we successfully synthesized Ru co-catalysts with distinct crystal phases [...] Read more.
This work aims to explore the influence of crystal phase engineering on the photocatalytic hydrogen evolution activity of Ru/C3N4 systems. By precisely tuning the combination of Ru precursors and reducing solvents, we successfully synthesized Ru co-catalysts with distinct crystal phases (hcp and fcc) and integrated them with C3N4. The photocatalytic hydrogen evolution experiments demonstrated that hcp-Ru/C3N4 achieved a significantly higher hydrogen evolution rate (24.23 μmol h−1) compared to fcc-Ru/C3N4 (7.44 μmol h−1), with activity reaching approximately 42% of Pt/C3N4 under the same conditions. Photocurrent and electrochemical impedance spectroscopy analyses revealed that hcp-Ru/C3N4 exhibited superior charge separation and transfer efficiency. Moreover, Gibbs free energy calculations indicated that the hydrogen adsorption energy of hcp-Ru (ΔGH* = −0.14 eV) was closer to optimal compared to fcc-Ru (−0.32 eV), enhancing the hydrogen generation process. These findings highlight that crystal-phase engineering plays a critical role in tuning the electronic structure and catalytic properties of Ru-based systems, offering insights for the design of highly efficient noble metal catalysts for photocatalysis. Full article
(This article belongs to the Special Issue Advanced Materials for Solar Energy Utilization)
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14 pages, 2707 KiB  
Article
Revealing the Electronic Effects Between Pt and W on the Performance of Selective Catalytic Reduction of NOx with H2 over Pt-W/SSZ-13
by Hongyan Zhao, Yan Li, Yan Huang, Jianli Wang, Yaoqiang Chen and Haidi Xu
Catalysts 2025, 15(3), 269; https://doi.org/10.3390/catal15030269 - 12 Mar 2025
Cited by 1 | Viewed by 386
Abstract
Selective catalytic reduction of NOx with H2 (H2-SCR) is crucial for eliminating NOx emissions from hydrogen internal combustion engines (H2-ICE). Although 1 wt.% Pt/SSZ-13 (Pt/SZ) is a promising H2-SCR catalyst, it faces challenges such [...] Read more.
Selective catalytic reduction of NOx with H2 (H2-SCR) is crucial for eliminating NOx emissions from hydrogen internal combustion engines (H2-ICE). Although 1 wt.% Pt/SSZ-13 (Pt/SZ) is a promising H2-SCR catalyst, it faces challenges such as a narrow operating window and low N2 selectivity. Herein, the effects of WO3 on improving the H2-SCR performance of Pt/SZ was investigated. Results showed that incorporating 5 wt.% WO3 significantly widened the temperature window for 80% NOx conversion and enhanced N2 selectivity at 90–180 °C. Several characterizations revealed that electrons transfer from W to Pt, so more active Pt0 species were formed on 1 wt.% Pt-5 wt.% W/SZ (Pt-5W/SZ). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis indicated that more active monodentate nitrates, nitrites, and NH4+ species were generated on Pt-5W/SZ, which are key intermediates for N2 formation. Consequently, the temperature windows for NOx conversion (over 80%) and N2 selectivity (over 70%) were widened by 65 °C and 66 °C, respectively. This work provides insights into the developing H2-SCR catalysts with broader operating windows and higher N2 selectivity. Full article
(This article belongs to the Special Issue Rare Metal Catalysis: From Synthesis to Sustainable Applications)
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13 pages, 3227 KiB  
Article
Development of a Multi-Bed Catalytic Heat Generator Utilizing a Palladium-Based Hydrogen Combustion System
by Grzegorz Mordarski, Konrad Skowron, Dorota Duraczyńska, Anna Drabczyk and Robert P. Socha
Energies 2025, 18(6), 1348; https://doi.org/10.3390/en18061348 - 10 Mar 2025
Viewed by 196
Abstract
The growing demand for sustainable energy solutions requires the development of safe and efficient systems for hydrogen utilization. Hydrogen, with its high energy density and clean combustion characteristics, has become a promising alternative for heating applications. However, conventional combustion technologies often suffer from [...] Read more.
The growing demand for sustainable energy solutions requires the development of safe and efficient systems for hydrogen utilization. Hydrogen, with its high energy density and clean combustion characteristics, has become a promising alternative for heating applications. However, conventional combustion technologies often suffer from inefficiencies and safety concerns, such as NOx emissions and explosion risks. To address these challenges, this study aimed to design and evaluate a catalytic heat generator utilizing hydrogen–air mixtures under controlled conditions to eliminate the need for pure oxygen and mitigate associated risks. A single-bed catalytic system was developed using palladium-based catalysts supported on ceramic fibers, followed by its heating, activation, and further characterization using the SEM-EDS technique. A multi-bed generator was later constructed to enhance scalability and performance. Thermal imaging and temperature monitoring were employed to optimize activation processes and assess system performance under varying hydrogen flow rates. The experimental results demonstrated efficient heat transfer and operational stability. Full article
(This article belongs to the Special Issue Hydrogen Production and Utilization: Challenges and Opportunities)
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19 pages, 3665 KiB  
Article
Harnessing Nitrous Oxide for Sustainable Methane Activation: A Computational Exploration of CNC-Ligated Iron Catalysts
by Bruce M. Prince
Methane 2025, 4(1), 6; https://doi.org/10.3390/methane4010006 - 5 Mar 2025
Viewed by 330
Abstract
This study employs DFT at the APFD/def2-TZVP level, with SMD solvation in THF, to investigate the catalytic activation of methane by [(κ3-CNC)Fe(N₂O)]2+ cation complexes. The catalytic mechanism encompasses three key steps: oxygen atom transfer (OAT), hydrogen atom abstraction (HAA), and [...] Read more.
This study employs DFT at the APFD/def2-TZVP level, with SMD solvation in THF, to investigate the catalytic activation of methane by [(κ3-CNC)Fe(N₂O)]2+ cation complexes. The catalytic mechanism encompasses three key steps: oxygen atom transfer (OAT), hydrogen atom abstraction (HAA), and oxygen radical rebound (ORR). The computational results identify OAT as the rate-determining step, with activation barriers of −10.2 kcal/mol and 5.0 kcal/mol for κ1-O- and κ1-N-bound intermediates in the gas and solvent phases, respectively. Methane activation proceeds via HAA, with energy barriers of 16.0–25.2 kcal/mol depending on the spin state and solvation, followed by ORR, which occurs efficiently with barriers as low as 6.4 kcal/mol. The triplet (S = 1) and quintet (S = 2) spin states exhibit critical roles in the catalytic pathway, with intersystem crossing facilitating optimal reactivity. Spin density analysis highlights the oxyl radical character of the FeIV=O intermediate as being essential for activating methane’s strong C–H bond. These findings underscore the catalytic potential of CNC-ligated iron complexes for methane functionalization and demonstrate their dual environmental benefits by utilizing methane and reducing nitrous oxide, a potent greenhouse gas. Full article
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17 pages, 3189 KiB  
Article
Transition Metal Oxides (WO3-ZrO2) as Promoters and Hydrogen Adsorption Modulators in Pt/WO3-ZrO2-C Electrocatalyst for the Reduction of NOx
by Claudia R. Santiago-Ramírez, Martha L. Hernández-Pichardo, Arturo Manzo-Robledo, Daniel A. Acuña-Leal and Miguel A. Gracia-Pinilla
Electrochem 2025, 6(1), 7; https://doi.org/10.3390/electrochem6010007 - 5 Mar 2025
Viewed by 527
Abstract
The electrocatalytic reduction of nitric oxide and nitrogen dioxide (NOx) remains a significant challenge due to the need for stable, efficient, and cost-effective materials. This study presents a novel support system for NOx reduction in alkaline media, composed of ZrO2-WO3 [...] Read more.
The electrocatalytic reduction of nitric oxide and nitrogen dioxide (NOx) remains a significant challenge due to the need for stable, efficient, and cost-effective materials. This study presents a novel support system for NOx reduction in alkaline media, composed of ZrO2-WO3-C (ZWC), synthesized via coprecipitation. Platinum nanoparticles (10 wt.%) were loaded onto ZWC and Vulcan carbon support, using similar methods for comparison. Comprehensive physicochemical and electrochemical analyses (N2 physisorption, XRD, XPS, SEM, TEM, and cyclic and linear voltammetry) revealed that PtZWC outperformed PtC and commercial PtEtek in NOx electrocatalysis. Notably, PtZWC exhibited the highest total electric charge for NOx reduction. At the same time, the hydrogen evolution reaction (HER) was shifted to more negative cathodic potentials, indicating reduced hydrogen coverage and a modified dissociative Tafel mechanism on platinum. Additionally, the combination of WO3 and ZrO2 in ZWC enhanced electron transfer and suppressed HER by reducing NO and hydrogen atom adsorption competition. While the incorporation of WO3 and ZrO2 lowered the surface area to 96 m2/g, it significantly improved pore properties, facilitating better Pt nanoparticle dispersion (3.06 ± 0.85 nm, as confirmed by SEM and TEM). XRD analysis identified graphite and Pt phases, with monoclinic WO3 broadening PtZWC peaks (20–25°). At the same time, XPS confirmed oxidation states of Pt, W, and Zr and tungsten-related oxygen vacancies, ensuring chemical stability and enhanced catalytic activity. Full article
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27 pages, 3788 KiB  
Article
Operative Improvement in the Naphtha Catalytic Reforming Process to Reduce the Environmental Impact of Benzene Fugitive Emissions from Gasoline
by Fabiola Velázquez-Alonso, César Abelardo González-Ramírez, José Roberto Villagómez-Ibarra, Elena María Otazo-Sánchez, Martín Hernández-Juárez, Fernando Pérez-Villaseñor, Ángel Castro-Agüero, Laura Olivia Alemán-Vázquez, César Camacho-López and Claudia Romo-Gómez
ChemEngineering 2025, 9(2), 21; https://doi.org/10.3390/chemengineering9020021 - 21 Feb 2025
Viewed by 608
Abstract
A challenge for the oil refinement industry is the production of high-octane gasoline with a low benzene content. This work reports the calculation of the atmospheric benzene emissions generated from gasoline storage, transfer, and transport operations in Mexico, estimating 1.48 KBPD of environmental [...] Read more.
A challenge for the oil refinement industry is the production of high-octane gasoline with a low benzene content. This work reports the calculation of the atmospheric benzene emissions generated from gasoline storage, transfer, and transport operations in Mexico, estimating 1.48 KBPD of environmental release. The aim was to estimate the minimum benzene emissions through operative improvements in refineries, initially by performing simulations of the Naphtha Catalytic Reforming (NCR) process using ASPEN HYSYS® ver. 8.8 (34.0.08909) and then by optimizing the operative conditions to improve the reformate quality while reducing the benzene content. The operative ranges comprised hydrogen/hydrocarbon (H2/HC) feedstock molar ratios from 2.0 to 6.0 and reaction temperatures from 450 to 525 °C, which were used as independent variables to assess the benzene content and the Research Octane Number (RON) of the produced gasoline. The Surface Response Method (SRM) and multi-objective optimization analysis were applied. The improved operative conditions were 491 °C and a H2/HC ratio of 2.0, which allowed us to obtain a RON value of 89.87, an aromatics value of 37.39% (v/v), and a benzene value of 1.48% (v/v), with an estimated 16.44% drop in atmospheric benzene emissions, meaning a reduction in greenhouse gas emissions and climate change, thus favorably impacting public health by improving refinery operations. The simulation outcomes were compared with industrial-scale data and the experimental results, with significant similitudes being observed. Full article
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14 pages, 2081 KiB  
Article
Theoretical Investigation of Single-Atom Catalysts for Hydrogen Evolution Reaction Based on Two-Dimensional Tetragonal V2C2 and V3C3
by Bo Xue, Qingfeng Zeng, Shuyin Yu and Kehe Su
Materials 2025, 18(5), 931; https://doi.org/10.3390/ma18050931 - 20 Feb 2025
Viewed by 212
Abstract
Developing stable and effective catalysts for the hydrogen evolution reaction (HER) has been a long-standing pursuit. In this work, we propose a series of single-atom catalysts (SACs) by importing transition-metal atoms into the carbon and vanadium vacancies of tetragonal V2C2 [...] Read more.
Developing stable and effective catalysts for the hydrogen evolution reaction (HER) has been a long-standing pursuit. In this work, we propose a series of single-atom catalysts (SACs) by importing transition-metal atoms into the carbon and vanadium vacancies of tetragonal V2C2 and V3C3 slabs, where the transition-metal atoms refer to Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. By means of first-principles computations, the possibility of applying these SACs in HER catalysis was investigated. All the SACs are conductive, which is favorable to charge transfer during HER. The Gibbs free energy change (ΔGH*) during hydrogen adsorption was adopted to assess their catalytic ability. For the V2C2-based SACs with V, Cr, Mn, Fe, Ni, and Cu located at the carbon vacancy, excellent HER catalytic performance was achieved, with a |ΔGH*| smaller than 0.2 eV. Among the V3C3-based SACs, apart from the SAC with Mn located at the carbon vacancy, all the SACs can act as outstanding HER catalysts. According to the ΔGH*, these excellent V2C2- and V3C3-based SACs are comparable to the best-known Pt-based HER catalysts. However, it should be noted that the V2C2 and V3C3 slabs have not been successfully synthesized in the laboratory, leading to a pure investigation without practical application in this work. Full article
(This article belongs to the Special Issue Advances in Multicomponent Catalytic Materials)
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13 pages, 3773 KiB  
Article
Transition-Metal-Doped Nickel–Cobalt Layered Double Hydroxide Catalysts for an Efficient Oxygen Evolution Reaction
by Zhihan Li, Wenjing Yi, Qingqing Pang, Meng Zhang and Zhongyi Liu
Materials 2025, 18(4), 877; https://doi.org/10.3390/ma18040877 - 17 Feb 2025
Viewed by 606
Abstract
Hydrogen plays a vital role in the global shift toward cleaner energy solutions, with water electrolysis standing out as one of the most promising techniques for generating hydrogen. Despite its potential, the oxygen evolution reaction (OER) involved in this process faces significant challenges, [...] Read more.
Hydrogen plays a vital role in the global shift toward cleaner energy solutions, with water electrolysis standing out as one of the most promising techniques for generating hydrogen. Despite its potential, the oxygen evolution reaction (OER) involved in this process faces significant challenges, including high overpotentials and slow reaction rates, which underscore the need for advanced electrocatalytic materials to enhance efficiency. Noble metal catalysts are effective but expensive, so transition-metal-based electrocatalysts like nickel–cobalt layered double hydroxides (NiCo LDHs) have become promising alternatives. In this research, a series of NiCo LDH catalysts doped with Fe, Mn, Cu, and Zn were effectively produced using a one-step hydrothermal technique. Among the catalysts, the Fe-doped NiCo LDH exhibited OER activity, achieving a lower overpotential (289 mV) at a current density of 50 mA/cm2, which was far better than the 450 mV of the undoped NiCo LDH. The Mn-, Cu-, and Zn-NiCo LDHs also exhibited lower overpotentials of 414 mV, 403 mV, and 357 mV, respectively, at this current density. The Fe-doped NiCo LDH had a 3D layered nanoflower structure, increasing the surface area for reactant adsorption. The electrochemically active surface area (ECSA), as indicated by the double-layer capacitance (Cdl), was larger in the doped samples. The Cdl value of the Fe-doped NiCo LDH was 3.72 mF/cm2, significantly surpassing the 0.82 mF/cm2 of the undoped NiCo LDH. These changes improved charge transfer and optimized reaction kinetics, enhancing the overall OER performance. This study offers significant contributions to the development of efficient electrocatalysts for the OER, advancing the understanding of key design principles for enhanced catalytic performance. Full article
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