Journal Description
Catalysts
Catalysts
is a peer-reviewed open access journal of catalysts and catalyzed reactions published monthly online by MDPI. The Romanian Catalysis Society (RCS) are partners of Catalysts journal and its members receive a discount on the article processing charge.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, CAPlus / SciFinder, CAB Abstracts, and other databases.
- Journal Rank: JCR - Q2 (Chemistry, Physical) / CiteScore - Q1 (General Environmental Science)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 14.3 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
3.9 (2022);
5-Year Impact Factor:
4.2 (2022)
Latest Articles
Kinetic and Mechanistic Study of Aldose Conversion to Functionalized Furans in Aqueous Solutions
Catalysts 2024, 14(3), 199; https://doi.org/10.3390/catal14030199 - 18 Mar 2024
Abstract
Reaction mixtures of naturally abundant aldoses and CH nucleophiles allow for the formation of functionalized furan precursors using low temperatures and metal-free catalysis in aqueous solutions of dilute base catalysts. We employ in situ NMR assays to clarify the mechanism and kinetics of
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Reaction mixtures of naturally abundant aldoses and CH nucleophiles allow for the formation of functionalized furan precursors using low temperatures and metal-free catalysis in aqueous solutions of dilute base catalysts. We employ in situ NMR assays to clarify the mechanism and kinetics of the conversion. Catalysis serves a double role in ring-opening of stable aldoses such as glucose and xylose and facilitating the subsequent reactions with CH acids such as malononitrile or cyanoacetamide. Resultant acyclic products are shown to convert quickly to a monocyclic product prior to the slower formation of a more stable bicyclic intermediate and dehydration to tri-functionalized furan. Especially the reversible 5-exo-dig ring closure entailing oxygen attack onto a nitrile carbon is surprisingly fast with an equilibrium vastly towards the cyclic state, sequestering reactive groups and allowing the selective conversion to tri-functionalized furan. The reaction hinges on the fast formation of intermediates without CH acidity and competes with the oligomerization of CH nucleophiles. Insight derived from in situ NMR analysis shows the prowess of high-resolution in situ spectroscopy in clarifying the interplay between catalysts and reactants. Such insight will be vital for the optimization of reactions that upgrade biorenewables under benign conditions.
Full article
(This article belongs to the Special Issue Novel Catalytic Strategies for the Synthesis of Furans and Their Derivatives)
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Open AccessArticle
Hydrodesulfurization of Thiophene in n-Heptane Stream Using CoMo/SBA-15 and CoMo/AlSBA-15 Mesoporous Catalysts
by
Ana Carla S. L. S. Coutinho, Joana M. F. Barros, Marcio D. S. Araujo, Jilliano B. Silva, Marcelo J. B. Souza, Regina C. O. B. Delgado, Valter J. Fernandes Jr. and Antonio S. Araujo
Catalysts 2024, 14(3), 198; https://doi.org/10.3390/catal14030198 - 18 Mar 2024
Abstract
Heterogeneous catalysts containing cobalt and molybdenum supported on mesoporous materials types SBA-15 and AlSBA-15 were synthesized for application in the HDS reactions of thiophene in the n-heptane stream. The materials were synthesized by the hydrothermal method using Pluronic P123 as a template. The
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Heterogeneous catalysts containing cobalt and molybdenum supported on mesoporous materials types SBA-15 and AlSBA-15 were synthesized for application in the HDS reactions of thiophene in the n-heptane stream. The materials were synthesized by the hydrothermal method using Pluronic P123 as a template. The calcined SBA-15 and AlSBA-15 supports were submitted to co-impregnation with solutions of cobalt nitrate and ammonium heptamolybdate, aiming for the production of 15% in mass of metal loading with an atomic ratio of [Co/(Co + Mo)] = 0.45. The obtained materials were dried and calcined to obtain the mesoporous catalysts in the forms of CoMo/SBA-15 and CoMo/AlSBA-15. The catalysts were characterized by XRD, TG/DTG, SEM, and nitrogen adsorption. From XRD analysis, it was verified that after the decomposition of the cobalt and molybdenum salts, MoO3, Co3O4, and CoMoO4 oxides were formed on the supports, being attributed to these chemical species, the activity for the HDS reactions. The catalytic activity of the obtained catalysts was evaluated in a continuously flowing tubular fixed-bed microreactor coupled on-line to a gas chromatograph, using an n-heptane stream containing 12,070 ppm of thiophene (ca. 5100 ppm of sulfur) as a model compound. The synthesized catalysts presented suitable activity for the HDS reaction, and the main obtained products were cis- and trans-2-butene, 1-butene, n-butane, and low amounts of isobutane. The presence of 1,3-butadiene and tetrahydrothiophene (THT) was not detected. A mechanism of the primary and secondary reactions and subsequent formation of the olefins and paraffins in the CoMo/SBA-15 and CoMo/AlSBA-15 mesoporous catalysts was proposed, considering steps of desulfurization, hydrogenation, dehydrogenation, THT decyclization, and isomerization.
Full article
(This article belongs to the Special Issue Microporous and Mesoporous Materials for Catalytic Applications)
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Open AccessArticle
Ru/Attapulgite as an Efficient and Low-Cost Ammonia Decomposition Catalyst
by
Qingfeng Teng, Junkang Sang, Guoxin Chen, Haoliang Tao, Yunan Wang, Hua Li, Wanbing Guan, Changsheng Ding, Fenghua Liu and Liangzhu Zhu
Catalysts 2024, 14(3), 197; https://doi.org/10.3390/catal14030197 - 16 Mar 2024
Abstract
On-site hydrogen generation from ammonia decomposition is a promising technology to address the challenges of direct transportation and storage of hydrogen. The main problems with the existing support materials for ammonia decomposition catalysts are their high cost and time-consuming preparation process. In this
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On-site hydrogen generation from ammonia decomposition is a promising technology to address the challenges of direct transportation and storage of hydrogen. The main problems with the existing support materials for ammonia decomposition catalysts are their high cost and time-consuming preparation process. In this work, ammonia decomposition catalysts consisting of in situ-formed nano-Ru particles supported on a naturally abundant mineral fiber, attapulgite (ATP), were proposed and studied. Also, 1 wt.% Ru was uniformly dispersed and anchored onto the surface of ATP fibers via the chemical method. We found that the calcination temperatures of the ATP support before the deposition of Ru resulted in little difference in catalytic performance, while the calcination temperatures of the 1Ru/ATP precursor were found to significantly influence the catalytic performance. The prepared 1 wt.% Ru/ATP catalyst (1Ru/ATP) without calcination achieved an ammonia conversion efficiency of 51% at 500 °C and nearly 100% at 600 °C, with the flow rate of NH3 being 10 sccm (standard cubic centimeter per minute). A 150 h continuous test at 600 °C showed that the 1Ru/ATP catalyst exhibited good stability with a degradation rate of about 0.01% h−1. The 1Ru/ATP catalyst was integrated with proton ceramic fuel cells (PCFCs). We reported that PCFCs at 650 °C offered 433 mW cm−2 under H2 fuel and 398 mW cm−2 under cracked NH3 fuel. The overall results suggest low-level Ru-loaded ATP could be an attractive, low-cost, and efficient ammonia decomposition catalyst for hydrogen production.
Full article
(This article belongs to the Special Issue Recent Advances and Strategies in the Development of Sustainable Metal Catalysts for Energy, Environment and Generation of High-Value Products)
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Open AccessArticle
Transformation of Light Alkanes into High-Value Aromatics
by
Muhammad Naseem Akhtar
Catalysts 2024, 14(3), 196; https://doi.org/10.3390/catal14030196 - 16 Mar 2024
Abstract
This research work is focused on the transformation of light alkane (propane) into high-value aromatics using gallo-alumino-silicate catalysts. Two sets of gallo-alumino-silicates were synthesized for this study. In the first set, the ratio of Ga/(Al+Ga) was modified, while the Si/(Al+Ga) ratio was held
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This research work is focused on the transformation of light alkane (propane) into high-value aromatics using gallo-alumino-silicate catalysts. Two sets of gallo-alumino-silicates were synthesized for this study. In the first set, the ratio of Ga/(Al+Ga) was modified, while the Si/(Al+Ga) ratio was held constant. In the subsequent set, the Si/(Al+Ga) ratio was adjusted, while maintaining a consistent Ga/(Al+Ga) ratio. This approach aimed to directly assess the impact of each ratio on catalyst performance. The comprehensive characterization of all catalysts was conducted using various instrumental techniques, i.e., BET surface area, XRD, NH3-TPD, 27Al, 71Ga and 29Si MAS NMR, and XPS. A gradual reduction in the percentage of crystallinity and rise in meso-surface area was noticed with a rise in Ga/(Al+Ga) ratio. The total acidity (NH3-TPD) demonstrated a decline as the Si/(Al+Ga) ratio increased, attributed to an overall decline in Al3+ or Ga3+ species. The XPS intensity of the Ga 2p3/2 peak rose in correlation with an elevated ratio of Ga/(Al+Ga), suggesting the formation of extra-framework Ga species. The propane conversion, aromatic yield, and aromatization/cracking ratio exhibited an increase with an increasing Ga/(Al+Ga) ratio, reaching an optimum value of 0.46 before declining. Conversely, an appreciable drop in the conversion of propane and yield of aromatics was detected with the rise in Si/(Al+Ga) ratio, attributing to the decline in acidity. The catalyst having a Ga/(Al+Ga) ration of 0.46 exhibited the highest propane conversion and aromatic yield of 83.0% and 55.0% respectively.
Full article
(This article belongs to the Special Issue Zeolites and Zeolite-Based Catalysts in Industrial Catalysis)
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Open AccessCommunication
Catalytic Activity Prediction of α-Diimino Nickel Precatalysts toward Ethylene Polymerization by Machine Learning
by
Zaheer Abbas, Md Mostakim Meraz, Wenhong Yang, Weisheng Yang and Wen-Hua Sun
Catalysts 2024, 14(3), 195; https://doi.org/10.3390/catal14030195 - 16 Mar 2024
Abstract
The present study explored machine learning methods to predict the catalytic activities of a dataset of 165 α-diimino nickel complexes in ethylene polymerization. Using 25 descriptors as the inputs, the XGBoost model presented the optimal performance among six different algorithms (R2
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The present study explored machine learning methods to predict the catalytic activities of a dataset of 165 α-diimino nickel complexes in ethylene polymerization. Using 25 descriptors as the inputs, the XGBoost model presented the optimal performance among six different algorithms (R2 = 0.999, Rt2 = 0.921, Q2 = 0.561). The results of the analysis indicate that high activity is related to the presence of polarizable atoms and less bulky substituents within the N-aryl group. This approach offers valuable insights on the variation principle of catalytic activity as a function of complex structure, helping to effectively design and optimize α-diimino Ni catalysts with desirable performance.
Full article
(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)
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Open AccessArticle
Origin of the Increase in the Selectivity of Ru Catalysts with the Addition of Amines in the Presence of ZnSO4 for the Selective Hydrogenation of Benzene to Cyclohexene
by
Haijie Sun, Wen Zhang, Xiaohui Wang, Zhihao Chen and Zhikun Peng
Catalysts 2024, 14(3), 194; https://doi.org/10.3390/catal14030194 - 13 Mar 2024
Abstract
The synthesis of nylon 6 and nylon 66 can be performed, starting with the selective hydrogenation of benzene to cyclohexene, which is deemed to be environmentally friendly and cost-saving and to have higher atom efficiency. Nano-Ru catalyst was synthesized via a precipitation method.
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The synthesis of nylon 6 and nylon 66 can be performed, starting with the selective hydrogenation of benzene to cyclohexene, which is deemed to be environmentally friendly and cost-saving and to have higher atom efficiency. Nano-Ru catalyst was synthesized via a precipitation method. The prepared catalyst was evaluated in the selective hydrogenation of benzene toward cyclohexene generation in the presence of ZnSO4 in a liquid batch reactor. The promotion effect of the addition of amines, i.e., ethylenediamine, ethanolamine, diethanolamine, and triethanolamine, was investigated. The fresh and spent catalysts were thoroughly characterized by XRD, TEM, AES, N2-sorption, FT-IR, and TPR. It was found that the addition of amines could significantly improve the catalytic selectivity toward cyclohexene formation in the presence of ZnSO4. This was attributed to the formation of (Zn(OH)2)5(ZnSO4)(H2O)x (x = 0.5, 3 or 4) through the reaction between ZnSO4 and the amines, which could be chemisorbed on the Ru surface. This led to retarding the formation of cyclohexane from the complete hydrogenation of benzene and, thus, increased the catalytic selectivity toward cyclohexene synthesis. Therefore, with the presence of ZnSO4, the amount of chemisorbed (Zn(OH)2)5(ZnSO4)(H2O)x increased with increasing amounts of added amines, leading to a decline in the catalytic activity toward benzene conversion and selectivity toward cyclohexene generation. When 7.6 mmol of diethanolamine and 10 g of ZrO2 were applied, the highest cyclohexene yields of 61.6% and 77.0% of benzene conversion were achieved over the Ru catalyst. Promising stability was demonstrated after six runs of catalytic experiments without regeneration. These achievements are not only promising for industrial application but also beneficial for designing other catalytic systems for selective hydrogenation.
Full article
(This article belongs to the Special Issue Applied Catalysis in Chemical Industry: Synthesis, Catalyst Design, and Evaluation, 2nd Edition)
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Open AccessReview
Air-Stable and Highly Active Transition Metal Phosphide Catalysts for Reductive Molecular Transformations
by
Takato Mitsudome
Catalysts 2024, 14(3), 193; https://doi.org/10.3390/catal14030193 - 12 Mar 2024
Abstract
This review introduces transition metal phosphide nanoparticle catalysts as highly efficient and reusable heterogeneous catalysts for various reductive molecular transformations. These transformations include the hydrogenation of nitriles to primary amines, reductive amination of carbonyl compounds, and biomass conversion, specifically, the aqueous hydrogenation reaction
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This review introduces transition metal phosphide nanoparticle catalysts as highly efficient and reusable heterogeneous catalysts for various reductive molecular transformations. These transformations include the hydrogenation of nitriles to primary amines, reductive amination of carbonyl compounds, and biomass conversion, specifically, the aqueous hydrogenation reaction of mono- and disaccharides to sugar alcohols. Unlike traditional air-unstable non-precious metal catalysts, these are stable in air, eliminating the need for strict anaerobic conditions or pre-reduction. Moreover, when combined with supports, metal phosphides exhibit significantly enhanced activity, demonstrating high activity, selectivity, and durability in these hydrogenation reactions.
Full article
(This article belongs to the Special Issue Exclusive Papers of the Editorial Board Members and Topical Advisory Panel Members of Catalysts in Section "Catalysis in Organic and Polymer Chemistry")
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Open AccessArticle
Influence of Oxide Coating Layers on the Stability of Gold Catalysts for Furfural Oxidative Esterification to Methyl Furoate
by
Juan Su, Nannan Zhan, Yuan Tan, Xiangting Min, Yan Xiao and Botao Qiao
Catalysts 2024, 14(3), 192; https://doi.org/10.3390/catal14030192 - 12 Mar 2024
Abstract
The use of gold nanoparticles (Au NPs) as catalysts has gained widespread attention in various reactions due to their high activity and selectivity under mild reaction conditions. However, one major challenge in utilizing these catalysts is their tendency to aggregate, leading to catalyst
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The use of gold nanoparticles (Au NPs) as catalysts has gained widespread attention in various reactions due to their high activity and selectivity under mild reaction conditions. However, one major challenge in utilizing these catalysts is their tendency to aggregate, leading to catalyst deactivation and hindering their amplification and industrial application. To overcome this issue, herein, we used a method by coating the surface of Au NPs with a thin layer of SiO2, which resulted in the formation of a superior catalyst denoted as Au@SiO2/ZA. Characterization studies revealed that the SiO2 layer is coated on the surface of Au NPs and effectively prevents the aggregation and growth of the gold particles during the reaction process, which makes the catalyst display excellent stability in furfural (FF) oxidative esterification to methyl furoate (MF). Moreover, the stabilization strategy is not limited to SiO2 alone. It can also be extended to other oxides such as ZrO2, CeO2, and TiO2. We believe this work will provide a good reference for the design and development of an efficient and stable gold catalyst for the oxidative esterification reaction.
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(This article belongs to the Section Nanostructured Catalysts)
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Open AccessArticle
CuSnBi Catalyst Grown on Copper Foam by Co-Electrodeposition for Efficient Electrochemical Reduction of CO2 to Formate
by
Hangxin Xie, Li Lv, Yuan Sun, Chunlai Wang, Jialin Xu and Min Tang
Catalysts 2024, 14(3), 191; https://doi.org/10.3390/catal14030191 - 11 Mar 2024
Abstract
Effective electrochemical reduction of carbon dioxide to formate under mild conditions helps mitigate the energy crisis but requires the use of high-performance catalysts. The addition of a third metal to the binary metal catalyst may further promote the electrochemical reduction of carbon dioxide
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Effective electrochemical reduction of carbon dioxide to formate under mild conditions helps mitigate the energy crisis but requires the use of high-performance catalysts. The addition of a third metal to the binary metal catalyst may further promote the electrochemical reduction of carbon dioxide to formate. Herein, we provided a co-electrodeposition method to grow CuSnBi catalysts on pretreated copper foam and discussed the effects of both pH value and molar ratio of metal ions (Cu2+, Sn2+, and Bi3+) in the electrodeposition solution on the electrocatalytic performance of CO2 to HCOO−. When the pH value of the electrodeposition solution was 8.5 and the molar ratio of Cu2+, Sn2+, and Bi3+ was 1:1:1, the electrode showed the highest FEHCOO− of 91.79% and the formate partial current density of 36.6 mA·cm−2 at −1.12 VRHE. Furthermore, the electrode kept stable for 20 h at −1.12 VRHE, and FEHCOO− was always beyond 85% during the electrolysis process, which is excellent compared to the previously reported ternary metal catalytic electrodes. This work highlights the vital impact of changes (pH value and molar ratio of metal ions) in electrodeposition liquid on catalytic electrodes and their catalytic performance, and refreshing the electrolyte is essential to maintain the activity and selectivity during the electrochemical reduction of CO2 to HCOO−.
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(This article belongs to the Section Electrocatalysis)
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The Influence of Sulfurization and Carbonization on Mo-Based Catalysts for CH3SH Synthesis
by
Hao Wang, Wenjun Zhang, Dalong Zheng, Yubei Li, Jian Fang, Min Luo, Jichang Lu and Yongming Luo
Catalysts 2024, 14(3), 190; https://doi.org/10.3390/catal14030190 - 11 Mar 2024
Abstract
Sulfur-resistant Mo-based catalysts have become promising for the one-step synthesis of methanethiol (CH3SH) from CO/H2/H2S, but the low reactant conversion and poor product selectivity have constrained its development. Herein, we synthesized K-MoS2/Al2O3
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Sulfur-resistant Mo-based catalysts have become promising for the one-step synthesis of methanethiol (CH3SH) from CO/H2/H2S, but the low reactant conversion and poor product selectivity have constrained its development. Herein, we synthesized K-MoS2/Al2O3 and K-Mo2C/Al2O3 catalysts via the sulfurization and carbonization of K-Mo-based catalysts in the oxidized state, respectively. During the synthesis of CH3SH, both K-Mo2C/Al2O3 and K-MoS2/Al2O3 showed excellent catalytic performance, and the activity of the former is superior to that of the latter. The effect of different treatments on the catalytic performance of Mo-based catalysts was investigated by XRD, BET, Raman spectroscopy, H2-TPR, and reactants-TPD characterization. The results showed that the sulfide-treated sample showed stronger metal-support interactions and contributed to the formation of K2S, which exposed more active sites and stabilized the formation of C-S bonds. Carbonized samples enhanced the activation of H2, which promoted the hydrogenation of the intermediate species of carbonyl sulfide (COS) and thus improved the selectivity of CH3SH.
Full article
(This article belongs to the Special Issue Synthesis and Application of Catalytic Materials in Energy and Environment, 2nd Edition)
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Open AccessReview
Recent Advances in Advanced Oxidation Processes for Degrading Pharmaceuticals in Wastewater—A Review
by
Nur Nabaahah Roslan, Harry Lik Hock Lau, Nurul Amanina A. Suhaimi, Nurulizzatul Ningsheh M. Shahri, Sera Budi Verinda, Muhammad Nur, Jun-Wei Lim and Anwar Usman
Catalysts 2024, 14(3), 189; https://doi.org/10.3390/catal14030189 - 10 Mar 2024
Abstract
A large variety of pharmaceutical compounds have recently been detected in wastewater and natural water systems. This review highlighted the significance of removing pharmaceutical compounds, which are considered indispensable emerging contaminants, from wastewater and natural water systems. Various advanced oxidation processes (AOPs), including
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A large variety of pharmaceutical compounds have recently been detected in wastewater and natural water systems. This review highlighted the significance of removing pharmaceutical compounds, which are considered indispensable emerging contaminants, from wastewater and natural water systems. Various advanced oxidation processes (AOPs), including UV-H2O2, Fenton and photo-Fenton, ozone-based processes, photocatalysis, and physical processes, such as sonolysis, microwave, and electron beam irradiation, which are regarded as the most viable methods to eliminate different categories of pharmaceutical compounds, are discussed. All these AOPs exhibit great promising techniques, and the catalytic degradation process of the emerging contaminants, advantages, and disadvantages of each technique were deliberated. Heterogeneous photocatalysis employing metal oxides, particularly anatase TiO2 nanoparticles as catalysts activated by UV light irradiation, was reviewed in terms of the electron–hole separation, migration of the charge carriers to the catalyst surfaces, and redox potential of the charge carriers. This brief overview also emphasized that anatase TiO2 nanoparticles and TiO2-based nanomaterials are promising photocatalysts, and a combination of photocatalysis and other AOPs enhanced photocatalytic degradation efficiency. Finally, the challenges of applying anatase TiO2-based photocatalysis in environmental remediation and wastewater treatments to degrade pharmaceutical compounds, including mass spectroscopic analysis and a biological activity test of by-products of the emerging contaminants resulting from photocatalysis, are summarized.
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(This article belongs to the Special Issue Advanced Catalytic Materials and Processes for Water/Wastewater Treatment)
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Deciphering the Pivotal Reaction Conditions for Hydrogen Production from Tar Catalytic Cracking by Perovskite
by
Wang-Mi Chen, Bei-Dou Xi, Ming-Xiao Li, Mei-Ying Ye, Jia-Qi Hou, Yu-Fang Wei, Cheng-Ze Yu and Fan-Hua Meng
Catalysts 2024, 14(3), 188; https://doi.org/10.3390/catal14030188 - 10 Mar 2024
Abstract
The catalytic cracking of pyrolysis gasification tar into H2 has garnered significant attention due to its exceptional conversion efficiency. In this study, the effects of pollutant concentration, residence time, weight hourly space velocity (WHSV), and reaction temperature on the hydrogen performance of
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The catalytic cracking of pyrolysis gasification tar into H2 has garnered significant attention due to its exceptional conversion efficiency. In this study, the effects of pollutant concentration, residence time, weight hourly space velocity (WHSV), and reaction temperature on the hydrogen performance of LaFe0.5Ni0.5O3 perovskite were comprehensively investigated. Results revealed that moderate pollutant concentration (0.3 g/L), low-medium residence time (250 SCCM), and low WHSV (0.24 gtoluene/(gcat·h)) facilitated efficient interaction between LaFe0.5Ni0.5O3 and toluene, thus achieving high hydrogen production. An increase in reaction temperature had minimal effect on the hourly hydrogen production above 700 °C but caused a significant increase in methane production. Additionally, the effects of oxygen evolution reactions, methane reactions, and methane catalytic cracking reactions of perovskite induced by different reaction conditions on tar cracking products were discussed in detail. Compared to previous reports, the biggest advantages of this system were that the hydrogen production per gram of tar was as high as 1.002 L/g, and the highest hydrogen content in gas-phase products reached 93.5%, which can maintain for approximately 6 h. Finally, LaFe0.5Ni0.5O3 showed good thermal stability, long-term stability, and catalyst reactivation potential.
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(This article belongs to the Section Industrial Catalysis)
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Investigating the Catalytic Deactivation of a Pd Catalyst during the Continuous Hydrogenation of CO2 into Formate Using a Trickle-Bed Reactor
by
Kwangho Park, Kyung Rok Lee, Sunghee Ahn, Hongjin Park, Seokyeong Moon, Sungho Yoon and Kwang-Deog Jung
Catalysts 2024, 14(3), 187; https://doi.org/10.3390/catal14030187 - 09 Mar 2024
Abstract
The practical application of formic acid production through the hydrogenation of CO2 has garnered significant attention in efforts to tackle the challenges associated with (1) achieving net-zero production of formic acid as a chemical feedstock and (2) improving hydrogen storage and transport.
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The practical application of formic acid production through the hydrogenation of CO2 has garnered significant attention in efforts to tackle the challenges associated with (1) achieving net-zero production of formic acid as a chemical feedstock and (2) improving hydrogen storage and transport. This study focuses on demonstrating the continuous operation of a trickle bed reactor for converting CO2 into formate using palladium on activated carbon (Pd/AC). Optimal temperature conditions were investigated through a dynamic operation for 24 h, achieving the maximum productivity of 2140 mmolFA·gPdsurf.−1·h−1 at 150 °C and 8 MPa, with an H2/CO2 ratio of 1:1; however, catalyst deactivation was observed in the process. Stability tests performed under continuous operation at 120 °C and 8 MPa with an H2/CO2 ratio of 1:1 indicated a gradual decline in productivity, culminating in a 20% reduction after 20 h. A comprehensive analysis comparing fresh and spent catalysts revealed that the diminished catalytic activity at elevated temperatures was attributed to the partial sintering and leaching of Pd nanoparticles during the hydrogenation process. These findings offer insights for the future development of novel Pd-based catalyst systems suitable for continuous hydrogenation processes.
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(This article belongs to the Special Issue Catalysis on Stable Molecules (CO2, CO, CH4, N2, NH3) Activation and Their Transformation, 2nd Edition)
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Open AccessFeature PaperArticle
Perovskite-Derivative Ni-Based Catalysts for Hydrogen Production via Steam Reforming of Long-Chain Hydrocarbon Fuel
by
Kai Guo, Hui Zhang, Changxuan Zhang, Xining Guo, Huiying Li and Zhourong Xiao
Catalysts 2024, 14(3), 186; https://doi.org/10.3390/catal14030186 - 08 Mar 2024
Abstract
Large-scale hydrogen production by the steam reforming of long-chain hydrocarbon fuel is highly desirable for fuel-cell application. In this work, LaNiO3 perovskite materials doped with different rare earth elements (Ce, Pr, Tb and Sm) were prepared by a sol-gel method, and the
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Large-scale hydrogen production by the steam reforming of long-chain hydrocarbon fuel is highly desirable for fuel-cell application. In this work, LaNiO3 perovskite materials doped with different rare earth elements (Ce, Pr, Tb and Sm) were prepared by a sol-gel method, and the derivatives supported Ni-based catalysts which were successfully synthesized by hydrogen reduction. The physicochemical properties of the as-prepared catalysts were characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, N2 adsorption–desorption isotherms, H2 temperature-programmed reduction, and X-ray photoelectron spectroscopy. The catalytic performance of the as-prepared catalysts for hydrogen production was investigated via the steam reforming of n-dodecane. The results showed that the catalyst forms perovskite oxides after calcination with abundant mesopores and macropores. After reduction, Ni particles were uniformly distributed on perovskite derivatives, and can effectively reduce the particles’ sizes by doping with rare earth elements (Ce, Pr, Tb and Sm). Compared with the un-doped catalyst, the activity and hydrogen-production rate of the catalysts are greatly improved with rare earth element (Ce, Pr, Tb and Sm)-doped catalysts, as well as the anti-carbon deposition performance. This is due to the strong interaction between the uniformly distributed Ni particles and the support, as well as the abundant oxygen defects on the catalyst surface.
Full article
(This article belongs to the Special Issue New Insights into Catalysis for Hydrogen Production and Fuel Conversion)
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Open AccessArticle
A Closed-Loop Biorefinery Approach for the Valorization of Winery Waste: The Production of Iron-Sulfonated Magnetic Biochar Catalysts and 5-Hydroxymethyl Furfural from Grape Pomace and Stalks
by
Luigi di Bitonto, Enrico Scelsi, Hilda Elizabeth Reynel-Ávila, Didilia Ileana Mendoza-Castillo, Adrián Bonilla-Petriciolet, Martin Hájek, Ahmad Mustafa and Carlo Pastore
Catalysts 2024, 14(3), 185; https://doi.org/10.3390/catal14030185 - 08 Mar 2024
Abstract
In this work, a closed-loop strategy for the management and valorization of winery waste was proposed. The exhausted pomace and grape stalks that are typically obtained from white wine industries were used as a source of simple sugars, namely, glucose and fructose, and
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In this work, a closed-loop strategy for the management and valorization of winery waste was proposed. The exhausted pomace and grape stalks that are typically obtained from white wine industries were used as a source of simple sugars, namely, glucose and fructose, and of lignocellulosic feedstock for the preparation of selective catalysts for the 5-hydroxymethylfurfural (5-HMF) production from fructose. A novel synthetic procedure was developed for the synthesis of iron-sulfonated magnetic biochar catalysts (Fe-SMBCs). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), BET surface area, porous structure analysis and determination of total amount of acid sites were performed in order to characterize the physico-chemical properties of the synthesized systems. Then, these heterogeneous catalysts were successfully tested via the dehydration of simple sugars into 5-HMF by using methyl isobutyl ketone (MIBK) and gamma valerolactone (GVL) as co-solvents. The optimum 5-HMF yield of 40.9 ± 1.1%mol with a selectivity of 59.8 ± 2.6%mol was achieved by adopting the following optimized conditions: 0.1 g of catalyst, volume ratio of GVL to H2O = 2 to 1, 403 K, 6 h. In addition, the catalyst was easily recycled using an external magnetic field and used for at least five reaction cycles without significant loss of catalytic activity.
Full article
(This article belongs to the Special Issue Biomass and Waste Valorization: Design and Construction of Novel Biocatalysts for Industrial Processing)
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Open AccessFeature PaperArticle
Ni Doped Co-MOF-74 Synergized with 2D Ti3C2Tx MXene as an Efficient Electrocatalyst for Overall Water-Splitting
by
Ke Yu, Jingyuan Zhang, Yuting Hu, Lanqi Wang, Xiaofeng Zhang and Bin Zhao
Catalysts 2024, 14(3), 184; https://doi.org/10.3390/catal14030184 - 07 Mar 2024
Abstract
Metal-organic framework (MOF)-based materials with abundant pore structure, large specific surface area, and atomically dispersed metal centers are considered as potential electrocatalysts for oxygen-evolution reaction (OER), while their ligand-saturated metal nodes are inert to electrocatalysis. In this work, heteroatom doping and interface engineering
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Metal-organic framework (MOF)-based materials with abundant pore structure, large specific surface area, and atomically dispersed metal centers are considered as potential electrocatalysts for oxygen-evolution reaction (OER), while their ligand-saturated metal nodes are inert to electrocatalysis. In this work, heteroatom doping and interface engineering are proposed to improve the OER performance of Co-MOF-74. Using two-dimensional Ti3C2Tx MXene as a conductive support, Ni-doped Co-MOF-74 (CoNi-MOF-74/MXene/NF) was in situ synthesized through a hydrothermal process, which exhibits excellent OER and hydrogen evolution reaction (HER) properties. For OER, the CoNi-MOF-74/MXene/NF achieves a current density of 100 mA/cm2 at an overpotential of only 256 mV, and a Tafel slope of 40.21 mV/dec. When used for HER catalysis, the current density of 10 mA/cm2 is reached at only 102 mV for the CoNi-MOF-74/MXene/NF. In addition, the two-electrode electrolyzer with CoNi-MOF-74/MXene/NF as both the cathode and anode only requires 1.49 V to reach the current density of 10 mA/cm2. This work provides a new approach for the development of bimetallic MOF-based electrocatalysts.
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(This article belongs to the Special Issue Green Energy and New Functional Materials through Catalysis for Carbon Neutrality)
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Open AccessFeature PaperArticle
Natural Wollastonite-Derived Two-Dimensional Nanosheet Ni3Si2O5(OH)4 as a Novel Carrier of CdS for Efficient Photocatalytic H2 Generation
by
Jiarong Ma, Run Zhou, Yu Tu, Ruixin Ma, Daimei Chen and Hao Ding
Catalysts 2024, 14(3), 183; https://doi.org/10.3390/catal14030183 - 06 Mar 2024
Abstract
Ni3Si2O5(OH)4 rods (NS) were synthesized via a hydrothermal method, employing natural wollastonite as a template. The hierarchical Ni3Si2O5(OH)4 rods exhibited vertically oriented nanosheets, resulting in a substantial increase in
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Ni3Si2O5(OH)4 rods (NS) were synthesized via a hydrothermal method, employing natural wollastonite as a template. The hierarchical Ni3Si2O5(OH)4 rods exhibited vertically oriented nanosheets, resulting in a substantial increase in the specific surface area (from 2.24 m2/g to 178.4 m2/g). Subsequently, a CdS/Ni3Si2O5(OH)4 composite photocatalyst (CdS/NS) was prepared using a chemical deposition method. CdS was uniformly loaded onto the surface of the Ni3Si2O5(OH)4 nanosheets, successfully forming a heterojunction with Ni3Si2O5(OH)4. The CdS/NS photocatalyst in the presence of lactic acid as a sacrificial agent demonstrated an impressive H2 production rate of 4.05 mmol h−1 g−1, around 40 times higher than pure CdS. The photocorrosion of CdS was effectively solved after loading. After four cycles, the performance of CdS/NS remained stable, showing the potential for sustainable applications. After photoexcitation, electrons moved from Ni3Si2O5(OH)4 to the valence band of CdS, where they interacted with the holes via an enhanced interface contact. Simultaneously, electrons in CdS transitioned to its conduction band, facilitating hydrogenation. The enhanced performance was attributed to the improved CdS dispersion by Ni3Si2O5(OH)4 loading and efficient photogenerated carrier separation through the heterojunction formation. This work provides new perspectives for broadening the applications of mineral materials and developing heterojunction photocatalysts with good dispersibility and recyclability.
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(This article belongs to the Special Issue Two-Dimensional Materials in Photo(electro)catalysis)
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Open AccessEditorial
The Industrial Catalysis Section: A Place to Publish Applied Catalysis Research
by
Guido Busca
Catalysts 2024, 14(3), 182; https://doi.org/10.3390/catal14030182 - 06 Mar 2024
Abstract
Chemical technologies provide processes for the large-scale production of materials (i [...]
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(This article belongs to the Section Industrial Catalysis)
Open AccessArticle
Catalytic and Capacitive Properties of Hierarchical Carbon–Nickel Nanocomposites
by
Hassan H. Hammud, Waleed A. Aljamhi, Dolayl E. Al-Hudairi, Nazish Parveen, Sajid Ali Ansari and Thirumurugan Prakasam
Catalysts 2024, 14(3), 181; https://doi.org/10.3390/catal14030181 - 05 Mar 2024
Abstract
Hierarchically graphitic carbon that contained nickel nanoparticles (HGC-Ni (1), (2), and (3)) were prepared by the pyrolysis of three metal complexes as follows: nickel 2,2′-biyridine dichloride, nickel terephthalate 2,2′-bipyridine, and nickel phenanthroline diaqua sulfate, respectively, in the presence of anthracene or pyrene. SEM
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Hierarchically graphitic carbon that contained nickel nanoparticles (HGC-Ni (1), (2), and (3)) were prepared by the pyrolysis of three metal complexes as follows: nickel 2,2′-biyridine dichloride, nickel terephthalate 2,2′-bipyridine, and nickel phenanthroline diaqua sulfate, respectively, in the presence of anthracene or pyrene. SEM indicated that the structure of the HGC-Ni samples consisted of nickel nanoparticles with a diameter of 20–500 nm embedded in a thin layer of a hierarchical graphitic carbon layer. The EDAX of HGC-Ni indicated the presence of nickel, carbon, and nitrogen. Chlorine, oxygen, and sulfur were present in (1), (2), and (3), respectively, due to the differences in their complex precursor type. XRD indicated that the nanoparticles consisted of Ni(0) atoms. The turnover frequency (TOF) for the reduction of p-nitrophenol (PNP) increased for catalysts HGC-Ni (3), (2), and (1) and were 0.0074, 0.0094, and 0.0098 mg PNP/mg catalyst/min, respectively. The TOF for the reduction of methyl orange (MO) increased for catalysts (3), (1), and (2) and were 0.0332, 0.0347, and 0.0385 mg MO/mg catalyst/min, respectively. Thus, nickel nano-catalysts (1) and (2) provided the highest performance compared to the nano-catalysts for the reduction of PNP and MO, respectively. The first-order rate constant (min−1) of HGC-Ni (3), with respect to the reduction of PNP, was 0.173 min−1, while the first-order rate constant (min−1) for the reduction of MO by HGC-Ni (1) was 0.404 min−1. HGC-Ni (3) had the highest number of cycles with respect to PNP (17.9 cycles) and MO (22.8 cycles). The catalysts were regenerated efficiently. HGC-Ni exhibited remarkable electrochemical capacitance characteristics in the present study. This material achieved a notable specific capacitance value of 320.0 F/g when measured at a current density of 2 A/g. Furthermore, its resilience was highlighted by its ability to maintain approximately 86.8% of its initial capacitance after being subjected to 2500 charge and discharge cycles. This finding suggests that this HGC-Ni composite stands out not only for its high capacitive performance but also for its durability, making it an attractive and potentially economical choice for energy-storage solutions in various technological applications.
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(This article belongs to the Special Issue Hollow and Porous Micro-/Nanostructured Materials in Catalysis)
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Open AccessArticle
Preparation of Proline-Modified UIO−66 Nanomaterials and Investigation of Their Potential in Lipase Immobilization
by
Xiaoxiao Dong, Chengnan Zhang, Prasanna J. Patil, Weiwei Li and Xiuting Li
Catalysts 2024, 14(3), 180; https://doi.org/10.3390/catal14030180 - 04 Mar 2024
Abstract
Metal–organic frameworks (MOFs) are regarded as excellent carriers for immobilized enzymes due to their substantial specific surface area, high porosity, and easily tunable pore size. Nevertheless, the use of UIO−66 material is significantly limited in immobilized enzymes due to the absence of active
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Metal–organic frameworks (MOFs) are regarded as excellent carriers for immobilized enzymes due to their substantial specific surface area, high porosity, and easily tunable pore size. Nevertheless, the use of UIO−66 material is significantly limited in immobilized enzymes due to the absence of active functional groups on its surface. This study comprised the synthesis of UIO−66 and subsequent modification of the proline (Pro) on UIO−66 through post-synthetic modification. UIO−66 and UIO−66/Pro crystals were employed as matrices to immobilize Rhizopus oryzae lipase (ROL). The contact angle demonstrated that the introduction of Pro onto UIO−66 resulted in favorable conformational changes in the structure of ROL. The immobilized enzyme ROL@UIO−66/Pro, produced via the covalent-bonding method, exhibited greater activity (0.064715 U/mg (about 1.73 times that of the free enzyme)) and stability in the ester hydrolysis reaction. The immobilized enzymes ROL@UIO−66 (131.193 mM) and ROL@UIO−66/Pro (121.367 mM), which were synthesized using the covalent-bonding approach, exhibited a lower Km and higher substrate affinity compared to the immobilized enzyme ROL@UIO−66/Pro (24.033 mM) produced via the adsorption method. This lays a solid foundation for the industrialization of immobilized enzymes.
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(This article belongs to the Special Issue Metal–Organic Framework Materials as Catalysts, 2nd Edition)
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