Guomin Li , Bin Wang , Xingchao Dai , Feng Shi , Yong Ding , Xinjiang Cui
The catalytic activity of NiV2Ox/Al2O3 for propane dehydrogenation (PDH) at 500 °C was observed to be 2–5 times higher than those of their monometallic counterparts, primarily attributed to the synergistic effect of Ni nanoparticles (NPs) and VOx. This synergy was concluded to promote not only the desorption of propylene but also the generation and desorption of H2, significantly improving the catalytic performance.
{"title":"Co-catalysis of propane dehydrogenation by Al2O3-supported Ni nanoparticles and VOx†","authors":"Guomin Li , Bin Wang , Xingchao Dai , Feng Shi , Yong Ding , Xinjiang Cui","doi":"10.1039/d4cy01216j","DOIUrl":"10.1039/d4cy01216j","url":null,"abstract":"<div><div>The catalytic activity of NiV<sub>2</sub>O<sub><em>x</em></sub>/Al<sub>2</sub>O<sub>3</sub> for propane dehydrogenation (PDH) at 500 °C was observed to be 2–5 times higher than those of their monometallic counterparts, primarily attributed to the synergistic effect of Ni nanoparticles (NPs) and VO<sub><em>x</em></sub>. This synergy was concluded to promote not only the desorption of propylene but also the generation and desorption of H<sub>2</sub>, significantly improving the catalytic performance.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 318-322"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nibras Hijazi , Juan Carlos Navarro de Miguel , Jose Luis Cerrillo , Rushana Khairova , Xuan Gong , Edy Abou-Hamad , Javier Ruiz-Martínez , Jorge Gascon
Alkene oligomerization represents an attractive methodology to produce environmentally friendly synthetic fuels, free of aromatics. However, the materials that catalyze this reaction undergo complex deactivation, the understanding of which remains elusive. To better understand deactivation, its mechanism and pathways, operando UV-vis spectroscopy has been implemented alongside solid-state NMR spectroscopy in the oligomerization of propene (at 523 K and 50–100 kPa of propene pressure) over highly acidic ZSM-5 and zeolite beta. Measured spectra reveal that deactivation is initiated by the formation of an allylic hydrocarbon pool comprising dienes and cyclopentenyl cations. This hydrocarbon pool acts as a scaffold for the formation of alkylated benzenes (e.g., 1,3-di-tert-butylbenzene) which, due to spatial limitations, end up retained as coke species. The hydrocarbon pool also mediates further growth of alkylated benzenes into polycyclic aromatic hydrocarbons, a process that forms larger coke species. However, as in the case of ZSM-5, this process can be retarded by the shape selectivity of the zeolite. The spectra also show that the formation of long oligomers (C14–C16), irrespective of their degree of branching, renders them entrapped within zeolite pores.
{"title":"Operando spectroscopy unravels the nature of deactivating species and their precursors in alkene oligomerization catalysis†","authors":"Nibras Hijazi , Juan Carlos Navarro de Miguel , Jose Luis Cerrillo , Rushana Khairova , Xuan Gong , Edy Abou-Hamad , Javier Ruiz-Martínez , Jorge Gascon","doi":"10.1039/d4cy01057d","DOIUrl":"10.1039/d4cy01057d","url":null,"abstract":"<div><div>Alkene oligomerization represents an attractive methodology to produce environmentally friendly synthetic fuels, free of aromatics. However, the materials that catalyze this reaction undergo complex deactivation, the understanding of which remains elusive. To better understand deactivation, its mechanism and pathways, <em>operando</em> UV-vis spectroscopy has been implemented alongside solid-state NMR spectroscopy in the oligomerization of propene (at 523 K and 50–100 kPa of propene pressure) over highly acidic ZSM-5 and zeolite beta. Measured spectra reveal that deactivation is initiated by the formation of an allylic hydrocarbon pool comprising dienes and cyclopentenyl cations. This hydrocarbon pool acts as a scaffold for the formation of alkylated benzenes (<em>e.g.</em>, 1,3-di-<em>tert</em>-butylbenzene) which, due to spatial limitations, end up retained as coke species. The hydrocarbon pool also mediates further growth of alkylated benzenes into polycyclic aromatic hydrocarbons, a process that forms larger coke species. However, as in the case of ZSM-5, this process can be retarded by the shape selectivity of the zeolite. The spectra also show that the formation of long oligomers (C<sub>14</sub>–C<sub>16</sub>), irrespective of their degree of branching, renders them entrapped within zeolite pores.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 376-385"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/cy/d4cy01057d?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hairu Wang , Yuying Bai , Rongling Wang , Yanan Fu , Qiong Mei , Bo Bai , Qizhao Wang
In the realm of photoelectrochemical (PEC) water splitting, the oxygen evolution reaction (OER) poses a significant efficiency bottleneck. To address this challenge, multi-interfacial optimization of BiVO4-based composites to enhance charge transport within the material matrix has emerged as a pivotal strategy for improving PEC performance. In this study, we present a comprehensive report on the design and fabrication of an innovative heterostructured NiFe-LDH/Co3O4/BiVO4 thin film. Through a series of meticulously designed experiments and characterization techniques, we delve into the operational mechanisms underlying the interfacial coupling effect of this composite photoanode. Notably, the sandwich-configured NiFe-LDH/Co3O4/BiVO4 photoanode demonstrates remarkable OER performance. Under standard solar simulation conditions, it achieves a photocurrent density of 4.7 mA cm−2 at 1.23 V vs. RHE in a 1.0 M KBi solution, marking a nearly fourfold enhancement compared to the pure BiVO4 photoanode. Our structural, compositional, and electrochemical analyses reveal that NiFe-LDH functions as a highly effective cocatalyst, substantially reducing the overpotential for water oxidation. Furthermore, the strategic incorporation of Co3O4 not only establishes a built-in electric field at the BiVO4 interface, thereby facilitating efficient charge separation, but also fine-tunes the electronic structure of the metal centres in NiFe-LDH, leading to an increased number of oxidation active sites. These synergistic effects significantly enhance the charge separation efficiency and long-term operational stability of the PEC system. These advancements are attributed to the intricate interfacial coupling between NiFe-LDH, Co3O4 nanoparticles, and BiVO4, underscoring the immense potential of this composite material in the domain of efficient photoelectrocatalysis.
在光电化学（PEC）水分解领域，析氧反应（OER）是一个重要的效率瓶颈。为了应对这一挑战，基于bivo4的复合材料的多界面优化，以增强材料基体内的电荷传输，已经成为提高PEC性能的关键策略。在这项研究中，我们全面报道了一种创新的异质结构NiFe-LDH/Co3O4/BiVO4薄膜的设计和制造。通过一系列精心设计的实验和表征技术，我们深入研究了这种复合光阳极界面耦合效应的操作机制。值得注意的是，三明治结构的nfe - ldh /Co3O4/BiVO4光阳极具有出色的OER性能。在标准太阳模拟条件下，在1.0 M KBi溶液中，与RHE相比，它在1.23 V下实现了4.7 mA cm−2的光电流密度，与纯BiVO4光阳极相比，光电流密度提高了近四倍。我们的结构、组成和电化学分析表明，NiFe-LDH作为一种高效的助催化剂，大大降低了水氧化的过电位。此外，Co3O4的战略性加入不仅在BiVO4界面上建立了内置电场，从而促进了有效的电荷分离，而且还微调了NiFe-LDH中金属中心的电子结构，导致氧化活性位点的数量增加。这些协同效应显著提高了电荷分离效率和PEC系统的长期运行稳定性。这些进展归功于nfe - ldh、Co3O4纳米颗粒和BiVO4之间复杂的界面耦合，强调了这种复合材料在高效光电催化领域的巨大潜力。
{"title":"Boosting photoelectrochemical water splitting: enhanced hole transport in BiVO4 photoanodes via interfacial coupling†","authors":"Hairu Wang , Yuying Bai , Rongling Wang , Yanan Fu , Qiong Mei , Bo Bai , Qizhao Wang","doi":"10.1039/d4cy01284d","DOIUrl":"10.1039/d4cy01284d","url":null,"abstract":"<div><div>In the realm of photoelectrochemical (PEC) water splitting, the oxygen evolution reaction (OER) poses a significant efficiency bottleneck. To address this challenge, multi-interfacial optimization of BiVO<sub>4</sub>-based composites to enhance charge transport within the material matrix has emerged as a pivotal strategy for improving PEC performance. In this study, we present a comprehensive report on the design and fabrication of an innovative heterostructured NiFe-LDH/Co<sub>3</sub>O<sub>4</sub>/BiVO<sub>4</sub> thin film. Through a series of meticulously designed experiments and characterization techniques, we delve into the operational mechanisms underlying the interfacial coupling effect of this composite photoanode. Notably, the sandwich-configured NiFe-LDH/Co<sub>3</sub>O<sub>4</sub>/BiVO<sub>4</sub> photoanode demonstrates remarkable OER performance. Under standard solar simulation conditions, it achieves a photocurrent density of 4.7 mA cm<sup>−2</sup> at 1.23 V <em>vs.</em> RHE in a 1.0 M KBi solution, marking a nearly fourfold enhancement compared to the pure BiVO<sub>4</sub> photoanode. Our structural, compositional, and electrochemical analyses reveal that NiFe-LDH functions as a highly effective cocatalyst, substantially reducing the overpotential for water oxidation. Furthermore, the strategic incorporation of Co<sub>3</sub>O<sub>4</sub> not only establishes a built-in electric field at the BiVO<sub>4</sub> interface, thereby facilitating efficient charge separation, but also fine-tunes the electronic structure of the metal centres in NiFe-LDH, leading to an increased number of oxidation active sites. These synergistic effects significantly enhance the charge separation efficiency and long-term operational stability of the PEC system. These advancements are attributed to the intricate interfacial coupling between NiFe-LDH, Co<sub>3</sub>O<sub>4</sub> nanoparticles, and BiVO<sub>4</sub>, underscoring the immense potential of this composite material in the domain of efficient photoelectrocatalysis.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 405-415"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jennifer Hong , Matteo Miola , Dominic Gerlach , Marc C. A. Stuart , Petra Rudolf , Dulce M. Morales , Loredana Protesescu , Paolo P. Pescarmona
In this work, we investigated the inherent electrocatalytic activity of nickel borides in an important reaction in the context of electrochemical valorization of biomass as the oxidation of hydroxymethylfurfural (5-HMF) to furan dicarboxylic acid (FDCA). For this purpose, nickel borides (NixB, x = 2 and 3) in the form of phase-pure nanocrystals (NCs) were synthesized through a solid-state synthesis method, supported on carbon paper and then tested as electrocatalysts for the oxidation of hydroxymethylfurfural (pH 12.9 or 13.9, 1.8 V vs. RHE, 3 h) by comparing their activity to that of Ni nanocrystals of similar average particle size (36–39 nm). Ni3B NCs achieved the highest 5-HMF conversion and Faradaic efficiency towards 5-HMF oxidation (Conv.5-HMF = 70%, FE = 94%), which is a markedly better performance compared to Ni2B NCs (Conv.5-HMF = 57%, FE = 72%) and to Ni nanoparticles (Conv.5-HMF = 58%, FE = 65%), thus unequivocally demonstrating for the first time the superior activity brought about by Ni3B. Based on a combination of physicochemical and electrochemical characterization (XPS, SEM, TEM, Cdl analysis), the better performance of the Ni3B-based electrocatalyst is attributed to differences in surface composition compared to the Ni2B-based electrocatalyst and to differences in terms of electrochemical surface area and/or bulk chemical features compared to the Ni-based electrocatalyst. Notably, these results were achieved with a remarkably low electrocatalyst loading (0.05 mg cm−2), leading to significantly higher turnover frequency compared to state-of-the-art nickel boride electrocatalysts for this reaction. A kinetic study showed that NixB NCs catalyze the electrosynthesis of FDCA from 5-HMF both through a direct and indirect mechanism, with the contribution of each changing as a function of the pH of the electrolyte.
在这项工作中，我们研究了在生物质电化学价值背景下，羟基甲基糠醛（5-HMF）氧化成呋喃二羧酸（FDCA）这一重要反应中，硼化镍的固有电催化活性。为此，采用固相合成法合成了相纯纳米晶（NCs）形式的硼化镍（NixB, x = 2和3），并将其负载在碳纸上，作为羟甲基糠醛（pH 12.9或13.9,1.8 V vs. RHE, 3 h）的电催化剂，与平均粒径相近（36-39 nm）的Ni纳米晶的活性进行了比较。Ni3B NCs的5-HMF转化率和5-HMF氧化的Faradaic效率最高（conv5 - hmf = 70%, FE = 94%），明显优于Ni2B NCs （conv5 - hmf = 57%, FE = 72%）和Ni纳米颗粒（conv5 - hmf = 58%, FE = 65%），从而首次明确证明了Ni3B所带来的优越活性。基于物理化学和电化学表征（XPS， SEM， TEM， Cdl分析）的结合，ni3b基电催化剂的更好性能归因于与ni2b基电催化剂相比表面组成的差异，以及与ni基电催化剂相比在电化学表面积和/或整体化学特征方面的差异。值得注意的是，这些结果是在非常低的电催化剂负载（0.05 mg cm - 2）下实现的，与最先进的硼化镍电催化剂相比，该反应的周转频率明显更高。动力学研究表明，NixB NCs通过直接和间接两种机制催化5-HMF电合成FDCA，两者的贡献随电解质pH值的变化而变化。
{"title":"An exploration of the electrocatalytic activity of nickel boride nanocrystals in the oxidation of 5-HMF†","authors":"Jennifer Hong , Matteo Miola , Dominic Gerlach , Marc C. A. Stuart , Petra Rudolf , Dulce M. Morales , Loredana Protesescu , Paolo P. Pescarmona","doi":"10.1039/d4cy01220h","DOIUrl":"10.1039/d4cy01220h","url":null,"abstract":"<div><div>In this work, we investigated the inherent electrocatalytic activity of nickel borides in an important reaction in the context of electrochemical valorization of biomass as the oxidation of hydroxymethylfurfural (5-HMF) to furan dicarboxylic acid (FDCA). For this purpose, nickel borides (Ni<sub><em>x</em></sub>B, <em>x</em> = 2 and 3) in the form of phase-pure nanocrystals (NCs) were synthesized through a solid-state synthesis method, supported on carbon paper and then tested as electrocatalysts for the oxidation of hydroxymethylfurfural (pH 12.9 or 13.9, 1.8 V <em>vs.</em> RHE, 3 h) by comparing their activity to that of Ni nanocrystals of similar average particle size (36–39 nm). Ni<sub>3</sub>B NCs achieved the highest 5-HMF conversion and Faradaic efficiency towards 5-HMF oxidation (Conv.<sub>5-HMF</sub> = 70%, FE = 94%), which is a markedly better performance compared to Ni<sub>2</sub>B NCs (Conv.<sub>5-HMF</sub> = 57%, FE = 72%) and to Ni nanoparticles (Conv.<sub>5-HMF</sub> = 58%, FE = 65%), thus unequivocally demonstrating for the first time the superior activity brought about by Ni<sub>3</sub>B. Based on a combination of physicochemical and electrochemical characterization (XPS, SEM, TEM, <em>C</em><sub>dl</sub> analysis), the better performance of the Ni<sub>3</sub>B-based electrocatalyst is attributed to differences in surface composition compared to the Ni<sub>2</sub>B-based electrocatalyst and to differences in terms of electrochemical surface area and/or bulk chemical features compared to the Ni-based electrocatalyst. Notably, these results were achieved with a remarkably low electrocatalyst loading (0.05 mg cm<sup>−2</sup>), leading to significantly higher turnover frequency compared to state-of-the-art nickel boride electrocatalysts for this reaction. A kinetic study showed that Ni<sub><em>x</em></sub>B NCs catalyze the electrosynthesis of FDCA from 5-HMF both through a direct and indirect mechanism, with the contribution of each changing as a function of the pH of the electrolyte.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 457-475"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/cy/d4cy01220h?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jane N. Agwara , Denis Leshchev , Sinhara M. H. D. Perera , Alexis K. Bauer , Michael L. Neidig , Marc D. Porosoff
Iron supported on ZSM-5 is a widely studied catalyst for Fischer–Tropsch synthesis (FTS). Iron is activated with H2, CO, or a mixture of CO and H2 prior to FTS, resulting in phase transformations that make it challenging to understand structure–property relationships. In this work, we demonstrate that increasing the pretreatment temperature of Fe–Na-ZSM-5 reduces CO conversion irrespective of the reductant, but the product selectivity, iron particle size, composition, CO adsorption properties, and zeolite structure is dependent on both the pretreatment temperature and reductant. Pretreatment of Fe–Na-ZSM-5 in H2 induces sintering of iron particles, increasing C2–C4 olefins and C5+ hydrocarbons selectivity from 19.0% and 14.0% at 350 °C to 28.2% and 25.4% at 770 °C, respectively. Conversely, CO pretreatment facilitates carbide formation, coke deposition, and CH4 formation.
{"title":"Effect of pretreatment conditions on Fe-ZSM-5 properties and performance for Fischer–Tropsch synthesis†","authors":"Jane N. Agwara , Denis Leshchev , Sinhara M. H. D. Perera , Alexis K. Bauer , Michael L. Neidig , Marc D. Porosoff","doi":"10.1039/d4cy00765d","DOIUrl":"10.1039/d4cy00765d","url":null,"abstract":"<div><div>Iron supported on ZSM-5 is a widely studied catalyst for Fischer–Tropsch synthesis (FTS). Iron is activated with H<sub>2</sub>, CO, or a mixture of CO and H<sub>2</sub> prior to FTS, resulting in phase transformations that make it challenging to understand structure–property relationships. In this work, we demonstrate that increasing the pretreatment temperature of Fe–Na-ZSM-5 reduces CO conversion irrespective of the reductant, but the product selectivity, iron particle size, composition, CO adsorption properties, and zeolite structure is dependent on both the pretreatment temperature and reductant. Pretreatment of Fe–Na-ZSM-5 in H<sub>2</sub> induces sintering of iron particles, increasing C<sub>2</sub>–C<sub>4</sub> olefins and C<sub>5+</sub> hydrocarbons selectivity from 19.0% and 14.0% at 350 °C to 28.2% and 25.4% at 770 °C, respectively. Conversely, CO pretreatment facilitates carbide formation, coke deposition, and CH<sub>4</sub> formation.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 435-447"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yi Pu , Ning Lu , Feiyu Jian , Ying Wang , Hui Tang
Fe–N–C electrocatalysts doped with heteroatoms are considered to be one of the most promising candidates to replace Pt-based materials and, hence, overcome the sluggish oxygen reduction reaction (ORR) for many energy conversion devices. Herein, a very facile strategy to prepare a Fe–P/N–C hybrid through pyrolyzing Fe/P-co-doped zeolitic imidazolate framework-8 (ZIF-8) was rationally designed. Characterizations exhibited that the Fe/P atoms were uniformly embedded in the N-doped carbon framework. Compared with the undoped precursor, the doped product showed considerably improved ORR performance with a more positive half-wave potential (E1/2 = 0.88 V) in alkaline media. When assembled as a cathode catalyst in a zinc–air battery, the product delivered a peak power density of 157.5 mW cm−2. This work provides a facile and novel design strategy for obtaining highly active ORR catalysts for Zn–air batteries.
{"title":"ZIF-8-derived Fe/P/N-co-doped carbon as efficient electrocatalysts for oxygen reduction reaction and zinc–air batteries†","authors":"Yi Pu , Ning Lu , Feiyu Jian , Ying Wang , Hui Tang","doi":"10.1039/d4cy01293c","DOIUrl":"10.1039/d4cy01293c","url":null,"abstract":"<div><div>Fe–N–C electrocatalysts doped with heteroatoms are considered to be one of the most promising candidates to replace Pt-based materials and, hence, overcome the sluggish oxygen reduction reaction (ORR) for many energy conversion devices. Herein, a very facile strategy to prepare a Fe–P/N–C hybrid through pyrolyzing Fe/P-co-doped zeolitic imidazolate framework-8 (ZIF-8) was rationally designed. Characterizations exhibited that the Fe/P atoms were uniformly embedded in the N-doped carbon framework. Compared with the undoped precursor, the doped product showed considerably improved ORR performance with a more positive half-wave potential (<em>E</em><sub>1/2</sub> = 0.88 V) in alkaline media. When assembled as a cathode catalyst in a zinc–air battery, the product delivered a peak power density of 157.5 mW cm<sup>−2</sup>. This work provides a facile and novel design strategy for obtaining highly active ORR catalysts for Zn–air batteries.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 501-505"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A generic chemical kinetic mechanism for nitric oxide reduction by ammonia is developed exploiting similarities in redox cycles exhibited by different catalysts. The mechanism comprises 28 reactions, the rate constants of which were estimated through analysis of the individual sub-processes and identifying the overall rate with the rate of the limiting step. The chemical kinetics so developed was used to simulate operation of several catalysts in a plug flow reactor. These simulations show that, after taking into account differences in feed gas composition, active site concentration and residence time, varying only one kinetic parameter, namely activation energy for the low-temperature catalytic site oxidation allows one to reconcile the observed differences between copper and iron exchanged zeolites and cerium dioxide with tungsta on titania. Prediction of the NO conversion by vanadia at high temperatures required changes of two kinetic parameters.
{"title":"Chemical kinetic mechanism for selective catalytic reduction of nitrogen oxides†","authors":"Alexey A. Burluka , Andrew P. Manning","doi":"10.1039/d4cy01205d","DOIUrl":"10.1039/d4cy01205d","url":null,"abstract":"<div><div>A generic chemical kinetic mechanism for nitric oxide reduction by ammonia is developed exploiting similarities in redox cycles exhibited by different catalysts. The mechanism comprises 28 reactions, the rate constants of which were estimated through analysis of the individual sub-processes and identifying the overall rate with the rate of the limiting step. The chemical kinetics so developed was used to simulate operation of several catalysts in a plug flow reactor. These simulations show that, after taking into account differences in feed gas composition, active site concentration and residence time, varying only one kinetic parameter, namely activation energy for the low-temperature catalytic site oxidation allows one to reconcile the observed differences between copper and iron exchanged zeolites and cerium dioxide with tungsta on titania. Prediction of the NO conversion by vanadia at high temperatures required changes of two kinetic parameters.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 547-562"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/cy/d4cy01205d?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Herein, we have presented the synthesis of two new NCSe pincer ligands by the reaction of 3-((phenylselanyl)methoxy)benzaldehyde () with alkyl amines (tbutylamine () and 1-adamantylamine ()). The reaction of ligands and with PdCl2(CH3CN)2 precursor resulted in the formation of palladium pincer complexes and , respectively. The newly designed compounds were characterized using various spectroscopic and analytical techniques like 1H and 13C{1H} nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy, high-resolution mass spectrometry (HRMS), and ultraviolet-visible (UV-visible) spectroscopy. The coordination mode of the ligand with palladium metal was authenticated with the help of single-crystal X-ray diffraction studies. Both palladium complexes showed distorted square planar geometry around the palladium center having NCSe pincer coordination mode. The NCSe palladium pincer complexes were utilized as a catalyst for regioselective cross-dehydrogenative coupling (CDC) of 2-arylthiophenes with hetero(arenes). Intriguingly, only 2.5 mol% catalyst loading is adequate for achieving higher yields (65–89%) of heterocoupled products. A broad substrate scope of hetero(arenes) showed excellent tolerance towards the developed protocol under mild reaction conditions and short reaction time. The poisoning experiments showed the homogeneous nature of the catalysis process. The plausible reaction mechanism was studied using control experiments and time-dependent HRMS studies. Among the complexes, the sterically bulky adamantyl side arm containing palladium pincer complex () showed a higher yield of CDC reaction.
{"title":"Pd(ii) NCSe–pincer complexes for regioselective cross-dehydrogenative coupling of arylthiophenes with hetero(arenes)†","authors":"Sohan Singh , Suman Mahala , Nattamai Bhuvanesh , Hemant Joshi","doi":"10.1039/d4cy01198h","DOIUrl":"10.1039/d4cy01198h","url":null,"abstract":"<div><div>Herein, we have presented the synthesis of two new NCSe pincer ligands by the reaction of 3-((phenylselanyl)methoxy)benzaldehyde () with alkyl amines (<sup><em>t</em></sup>butylamine () and 1-adamantylamine ()). The reaction of ligands and with PdCl<sub>2</sub>(CH<sub>3</sub>CN)<sub>2</sub> precursor resulted in the formation of palladium pincer complexes and , respectively. The newly designed compounds were characterized using various spectroscopic and analytical techniques like <sup>1</sup>H and <sup>13</sup>C{<sup>1</sup>H} nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy, high-resolution mass spectrometry (HRMS), and ultraviolet-visible (UV-visible) spectroscopy. The coordination mode of the ligand with palladium metal was authenticated with the help of single-crystal X-ray diffraction studies. Both palladium complexes showed distorted square planar geometry around the palladium center having NCSe pincer coordination mode. The NCSe palladium pincer complexes were utilized as a catalyst for regioselective cross-dehydrogenative coupling (CDC) of 2-arylthiophenes with hetero(arenes). Intriguingly, only 2.5 mol% catalyst loading is adequate for achieving higher yields (65–89%) of heterocoupled products. A broad substrate scope of hetero(arenes) showed excellent tolerance towards the developed protocol under mild reaction conditions and short reaction time. The poisoning experiments showed the homogeneous nature of the catalysis process. The plausible reaction mechanism was studied using control experiments and time-dependent HRMS studies. Among the complexes, the sterically bulky adamantyl side arm containing palladium pincer complex () showed a higher yield of CDC reaction.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 523-536"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Asad Saib , Roman Goy , Jonathan Medlock , Bettina Wüstenberg , Gabriele Kociok-Köhn , Catherine L. Lyall , John P. Lowe , Ulrich Hintermair
The catalytic anti-Markovnikov addition of carboxylic acids to propargylic alcohols to furnish unsaturated esters is an appealing transformation due to its mild conditions, good selectivity and high atom economy. Treatment of the γ-hydroxy α,β-unsaturated esters with Brønsted acids gives access to enals which serve as important building blocks for the production of vitamins and aroma compounds from biogenic terpenes. Unfortunately, current turnover numbers (TON) for this ruthenium-catalysed reaction are too low for industrial application (<100). Here we present a detailed investigation into the speciation and deactivation of the most active [(dppe)RuII(MA)2] catalyst in the anti-Markovnikov addition of carboxylic acids to ethynyl-β-ionol. Multi-nuclear high resolution FlowNMR spectroscopy gave insight into a range of kinetically relevant carboxylate complexes, allowed quantifying catalyst deactivation kinetics, and showed a pronounced influence of the carboxylic acid on catalyst stability. Systematic optimisation of reaction parameters resulted in significant improvements in catalyst productivity to reach TONs of >450 for ethynyl-β-ionol and >2000 for phenylacetylene.
{"title":"Catalyst speciation and deactivation in the ruthenium-mediated transformation of ethynyl-β-ionol to α,β-unsaturated esters for vitamin A synthesis†","authors":"Asad Saib , Roman Goy , Jonathan Medlock , Bettina Wüstenberg , Gabriele Kociok-Köhn , Catherine L. Lyall , John P. Lowe , Ulrich Hintermair","doi":"10.1039/d4cy01032a","DOIUrl":"10.1039/d4cy01032a","url":null,"abstract":"<div><div>The catalytic anti-Markovnikov addition of carboxylic acids to propargylic alcohols to furnish unsaturated esters is an appealing transformation due to its mild conditions, good selectivity and high atom economy. Treatment of the γ-hydroxy α,β-unsaturated esters with Brønsted acids gives access to enals which serve as important building blocks for the production of vitamins and aroma compounds from biogenic terpenes. Unfortunately, current turnover numbers (TON) for this ruthenium-catalysed reaction are too low for industrial application (<100). Here we present a detailed investigation into the speciation and deactivation of the most active [(dppe)Ru<sup>II</sup>(MA)<sub>2</sub>] catalyst in the anti-Markovnikov addition of carboxylic acids to ethynyl-β-ionol. Multi-nuclear high resolution FlowNMR spectroscopy gave insight into a range of kinetically relevant carboxylate complexes, allowed quantifying catalyst deactivation kinetics, and showed a pronounced influence of the carboxylic acid on catalyst stability. Systematic optimisation of reaction parameters resulted in significant improvements in catalyst productivity to reach TONs of >450 for ethynyl-β-ionol and >2000 for phenylacetylene.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 355-375"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/cy/d4cy01032a?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yacine Boudjema , Antoine Brunel , Raphaël Del Cerro , Gerhard Pirngruber , Céline Chizallet , Kim Larmier
Sn-β is a promising Lewis acid zeolite for carbohydrate conversion. This material can be prepared either directly by hydrothermal synthesis or by a dealumination – metal incorporation sequence starting from a pre-made zeolite (post-synthesis modification). The synthesis method and the metallic precursors significantly influence the formation of Lewis acid sites in the zeolite, which is the primary factor determining the activity of the catalyst in many reactions. We synthesized various materials through post-synthesis modifications and a hydrothermal method using three different precursors. Pyridine adsorption monitored by FTIR spectroscopy shows that Sn-β samples synthesized by solid state insertion with tin chloride as a precursor feature a concentration of Lewis acid sites proportional to the tin content (up to 1.5 wt% of tin) without forming an oxide phase. Hydrothermal synthesis leads to a sample exhibiting weaker acid sites. The catalyst yields three major products in glucose conversion: fructose, mannose, and lactic acid. The high yield of lactic acid (≈30%) indicates a faster ketose retro-aldolization compared to aldose (no C4 or C2 products detected).
{"title":"Relationship between Lewis acid sites and carbohydrate reactivity over Sn-β catalysts†","authors":"Yacine Boudjema , Antoine Brunel , Raphaël Del Cerro , Gerhard Pirngruber , Céline Chizallet , Kim Larmier","doi":"10.1039/d4cy01147c","DOIUrl":"10.1039/d4cy01147c","url":null,"abstract":"<div><div>Sn-β is a promising Lewis acid zeolite for carbohydrate conversion. This material can be prepared either directly by hydrothermal synthesis or by a dealumination – metal incorporation sequence starting from a pre-made zeolite (post-synthesis modification). The synthesis method and the metallic precursors significantly influence the formation of Lewis acid sites in the zeolite, which is the primary factor determining the activity of the catalyst in many reactions. We synthesized various materials through post-synthesis modifications and a hydrothermal method using three different precursors. Pyridine adsorption monitored by FTIR spectroscopy shows that Sn-β samples synthesized by solid state insertion with tin chloride as a precursor feature a concentration of Lewis acid sites proportional to the tin content (up to 1.5 wt% of tin) without forming an oxide phase. Hydrothermal synthesis leads to a sample exhibiting weaker acid sites. The catalyst yields three major products in glucose conversion: fructose, mannose, and lactic acid. The high yield of lactic acid (≈30%) indicates a faster ketose retro-aldolization compared to aldose (no C4 or C2 products detected).</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 2","pages":"Pages 396-404"},"PeriodicalIF":4.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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