This meta‐review attempts to systematically analyse the recent advancements in transition metal‐catalysed hydrogenation reactions as discussed in previous review articles, emphasising the computational insights that enhance our understanding of reaction mechanisms. It highlights the efficacy of density functional theory (DFT) in calculating free energies, exploring the mechanistic pathways and kinetics of hydrogenation processes, focusing on substrates such as alkenes, alkynes, amides, imines, nitriles, and carbon dioxide. The review details significant studies where computational models help predict reaction outcomes and aid in catalyst design. Notable discussions include the role of solvent effects and metal‐ligand interactions, which are crucial for reactivity and selectivity but often underestimated in computational models. The review concludes with current computational challenges and prospects, suggesting enhanced models and experimental collaborations to refine catalyst design.
{"title":"Revisiting the Reviewed: A Meta‐Analysis of Computational Studies on Transition Metal‐Catalysed Hydrogenation Reactions","authors":"Michael Bühl, Shahbaz Ahmad","doi":"10.1002/cctc.202401053","DOIUrl":"https://doi.org/10.1002/cctc.202401053","url":null,"abstract":"This meta‐review attempts to systematically analyse the recent advancements in transition metal‐catalysed hydrogenation reactions as discussed in previous review articles, emphasising the computational insights that enhance our understanding of reaction mechanisms. It highlights the efficacy of density functional theory (DFT) in calculating free energies, exploring the mechanistic pathways and kinetics of hydrogenation processes, focusing on substrates such as alkenes, alkynes, amides, imines, nitriles, and carbon dioxide. The review details significant studies where computational models help predict reaction outcomes and aid in catalyst design. Notable discussions include the role of solvent effects and metal‐ligand interactions, which are crucial for reactivity and selectivity but often underestimated in computational models. The review concludes with current computational challenges and prospects, suggesting enhanced models and experimental collaborations to refine catalyst design.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"11 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208751","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}
Aluminosilicate (Al‐SiO2) thin films with vertically aligned mesochannels were successfully synthesized on ITO electrodes and employed for the immobilization of a cationic Ru(II) water oxidation catalyst without requiring linker groups. Optimal synthesis conditions yielded uniform mesoporous Al‐SiO2 films with tunable Al content, high surface area (568 m2/g), 3.94 nm pore size, and 155 nm thickness. Electrochemical studies confirmed the presence of the immobilized Ru complex undergoing diffusion‐controlled Ru(III/II) and Ru(IV/III) electron transfer. The Ru loading reached 4.71 nmol/cm2 at Si/Al = 9.6, with higher Al content enhancing loading amounts via cation exchange. The Ru‐modified electrode exhibited high electrocatalytic water oxidation activity, achieving 75.3% Faradaic efficiency and a turnover number of 298.6 for O2 evolution for 1 hour. This work provides a new approach to construct porous environments on an electrode surface to immobilize positively charged transition‐metal complexes as catalysts, offering potential applications in the development of electrocatalytic systems for energy conversion.
{"title":"Construction of Mesoporous Aluminosilicate Thin Films on ITO Electrodes for Immobilizing a Cationic Ru(II) Water Oxidation Catalyst","authors":"Masaya Okamura, Shunpei Harada, Ayano Yamada, Narumi Nakano, Shiro Hikichi","doi":"10.1002/cctc.202401199","DOIUrl":"https://doi.org/10.1002/cctc.202401199","url":null,"abstract":"Aluminosilicate (Al‐SiO2) thin films with vertically aligned mesochannels were successfully synthesized on ITO electrodes and employed for the immobilization of a cationic Ru(II) water oxidation catalyst without requiring linker groups. Optimal synthesis conditions yielded uniform mesoporous Al‐SiO2 films with tunable Al content, high surface area (568 m2/g), 3.94 nm pore size, and 155 nm thickness. Electrochemical studies confirmed the presence of the immobilized Ru complex undergoing diffusion‐controlled Ru(III/II) and Ru(IV/III) electron transfer. The Ru loading reached 4.71 nmol/cm2 at Si/Al = 9.6, with higher Al content enhancing loading amounts via cation exchange. The Ru‐modified electrode exhibited high electrocatalytic water oxidation activity, achieving 75.3% Faradaic efficiency and a turnover number of 298.6 for O2 evolution for 1 hour. This work provides a new approach to construct porous environments on an electrode surface to immobilize positively charged transition‐metal complexes as catalysts, offering potential applications in the development of electrocatalytic systems for energy conversion.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"469 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208752","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}
Ranjan K. Behera, Andrew R. Lamkins, Minda Chen, Raghu V. Maligal-Ganesh, Jiaqi Yu, Wenyu Huang
There has been significant interest in developing new catalytic systems to convert linear chain alkanes into olefins and aromatics. In the case of higher alkanes (≥ C6), the production of aromatic compounds such as benzene‐toluene‐xylenes is highly desirable. However, as the length of the carbon chain increases, the dehydrogenation process becomes more complex, not only due to the challenges of C‐H activation but also the need for selectivity towards the desired products by the possibility of side reactions such as isomerization and cracking. Here, we present a detailed analysis of the dehydroaromatization of n‐hexane, n‐heptane, and n‐octane, using PtSn intermetallic nanoparticles supported on SBA‐15 as the catalyst. Through in‐situ spectroscopic and kinetic analysis, we have probed into the reaction kinetics, catalyst deactivation, and a mechanistic understanding of the dehydroaromatization process on the surface of the PtSn intermetallic nanoparticles. Introducing Sn has been shown to be crucial not only for enhancement of catalytic activity, but also for higher aromatics selectivity and stability on stream. Furthermore, the analysis of dehydroaromatization reaction rates of reactant and possible intermediates indicates that the dehydroaromatization of n‐hexane to benzene likely proceeds through initial dehydrogenation steps followed by ring closing.
{"title":"Non‐Oxidative Dehydroaromatization of Linear Alkanes on Intermetallic Nanoparticles","authors":"Ranjan K. Behera, Andrew R. Lamkins, Minda Chen, Raghu V. Maligal-Ganesh, Jiaqi Yu, Wenyu Huang","doi":"10.1002/cctc.202401263","DOIUrl":"https://doi.org/10.1002/cctc.202401263","url":null,"abstract":"There has been significant interest in developing new catalytic systems to convert linear chain alkanes into olefins and aromatics. In the case of higher alkanes (≥ C6), the production of aromatic compounds such as benzene‐toluene‐xylenes is highly desirable. However, as the length of the carbon chain increases, the dehydrogenation process becomes more complex, not only due to the challenges of C‐H activation but also the need for selectivity towards the desired products by the possibility of side reactions such as isomerization and cracking. Here, we present a detailed analysis of the dehydroaromatization of n‐hexane, n‐heptane, and n‐octane, using PtSn intermetallic nanoparticles supported on SBA‐15 as the catalyst. Through in‐situ spectroscopic and kinetic analysis, we have probed into the reaction kinetics, catalyst deactivation, and a mechanistic understanding of the dehydroaromatization process on the surface of the PtSn intermetallic nanoparticles. Introducing Sn has been shown to be crucial not only for enhancement of catalytic activity, but also for higher aromatics selectivity and stability on stream. Furthermore, the analysis of dehydroaromatization reaction rates of reactant and possible intermediates indicates that the dehydroaromatization of n‐hexane to benzene likely proceeds through initial dehydrogenation steps followed by ring closing.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"18 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208748","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}
Understanding the changes in the zeolite framework and catalytic active sites in zeolite‐based vapor‐phase and aqueous catalytic processes is crucial. Herein, the evolution of framework T atoms (Si and Al) in ammonium hexafluorosilicate (AHFS)‐treated HZSM‐5 zeolite under steam and hot liquid water (HLW) environments was inverstigated using various characterization techniques. In the HLW environment, Si‐O‐Si bonds exhibit poorer hydrothermal stability than Si‐O‐Al bonds, in contrast to the steam environment. Significant Si atom leaching occurs without or with the removal of framework tetrahedral Al atoms (Al(IV)‐1). Similar to steam, Al(IV)‐1 species in the HLW environment sequentially evolve into partially coordinated framework Al species and then into extra‐framework Al (EFAL) species through partial and complete hydrolysis. The generated EFAL species act as Lewis acid sites, but their local structures or chemical environments may differ. These findings reveal the difference in the T‐O‐T bonds attacked by water molecules: the Si‐O‐Al bonds is primarily attacked in steam, whereas the Si‐O‐Si bond is primarily attacked in HLW.
了解沸石气相和水相催化过程中沸石框架和催化活性位点的变化至关重要。在此，我们使用各种表征技术反演了经六氟硅酸铵（AHFS）处理的 HZSM-5 沸石在蒸汽和热液态水（HLW）环境下框架 T 原子（Si 和 Al）的演变。在 HLW 环境中，Si-O-Si 键的热液稳定性比 Si-O-Al 键差，这与蒸汽环境形成鲜明对比。在不去除或去除框架四面体 Al 原子（Al(IV)-1）的情况下，Si 原子会发生严重的沥滤。与蒸汽类似，高浓铀浓缩物环境中的 Al(IV)-1 物种通过部分和完全水解，依次演变为部分配位的框架 Al 物种，然后演变为框架外 Al (EFAL) 物种。生成的 EFAL 物种充当路易斯酸位点，但它们的局部结构或化学环境可能有所不同。这些发现揭示了水分子所攻击的 T-O-T 键的差异：蒸汽中主要攻击的是 Si-O-Al 键，而在 HLW 中主要攻击的是 Si-O-Si 键。
{"title":"Comparative Study of Si‐O‐Al and Si‐O‐Si Bond Stability in HZSM‐5 Zeolite Under Steam and Hot Liquid Water Environments","authors":"Linhai He, Jing Niu, Songyue Han, Dong Fan, Wenna Zhang, Shutao Xu, Yingxu Wei, Zhongmin Liu","doi":"10.1002/cctc.202401270","DOIUrl":"https://doi.org/10.1002/cctc.202401270","url":null,"abstract":"Understanding the changes in the zeolite framework and catalytic active sites in zeolite‐based vapor‐phase and aqueous catalytic processes is crucial. Herein, the evolution of framework T atoms (Si and Al) in ammonium hexafluorosilicate (AHFS)‐treated HZSM‐5 zeolite under steam and hot liquid water (HLW) environments was inverstigated using various characterization techniques. In the HLW environment, Si‐O‐Si bonds exhibit poorer hydrothermal stability than Si‐O‐Al bonds, in contrast to the steam environment. Significant Si atom leaching occurs without or with the removal of framework tetrahedral Al atoms (Al(IV)‐1). Similar to steam, Al(IV)‐1 species in the HLW environment sequentially evolve into partially coordinated framework Al species and then into extra‐framework Al (EFAL) species through partial and complete hydrolysis. The generated EFAL species act as Lewis acid sites, but their local structures or chemical environments may differ. These findings reveal the difference in the T‐O‐T bonds attacked by water molecules: the Si‐O‐Al bonds is primarily attacked in steam, whereas the Si‐O‐Si bond is primarily attacked in HLW.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"262 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208753","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}
Pan Zhu, Wuyi Feng, Jing Liu, Ting Liu, jiatao zhang, di zhao
The emerging atomic‐level synergistic catalysts based on the single‐atom sites and other valuable components, such as atom, cluster, nanoparticle and other nano‐matter, shine in various catalytic fields. They can integrate the advantages of individual catalytic sites and other valuable components to enhance the activity, selectivity and stability of many chemical reactions via activating their key rate‐determining steps and multistep transformations. In addition, because of the ultrahigh atom utilization (~100%) and adjustable microenvironment of metal centers, the single‐atom sites can intelligently construct with other useful large size sites to strengthening in tandem a typical catalytic process. Herein, the structure and mechanism of atomic‐level synergistic catalysts with controllable electronic structures and regulatory reaction processes are presented. We particularly emphasize the interactions between active components of atomic‐level synergistic catalysts and catalytic reaction processes, which are essential for understanding how these catalysts are cooperatively working. It is anticipated that this minireview can make the promotion of advanced atomic‐level synergistic catalysts based on single‐atom sites.
{"title":"Atomic‐level synergistic catalysts: single‐atom site integrated with atom, cluster and nanoparticle","authors":"Pan Zhu, Wuyi Feng, Jing Liu, Ting Liu, jiatao zhang, di zhao","doi":"10.1002/cctc.202401331","DOIUrl":"https://doi.org/10.1002/cctc.202401331","url":null,"abstract":"The emerging atomic‐level synergistic catalysts based on the single‐atom sites and other valuable components, such as atom, cluster, nanoparticle and other nano‐matter, shine in various catalytic fields. They can integrate the advantages of individual catalytic sites and other valuable components to enhance the activity, selectivity and stability of many chemical reactions via activating their key rate‐determining steps and multistep transformations. In addition, because of the ultrahigh atom utilization (~100%) and adjustable microenvironment of metal centers, the single‐atom sites can intelligently construct with other useful large size sites to strengthening in tandem a typical catalytic process. Herein, the structure and mechanism of atomic‐level synergistic catalysts with controllable electronic structures and regulatory reaction processes are presented. We particularly emphasize the interactions between active components of atomic‐level synergistic catalysts and catalytic reaction processes, which are essential for understanding how these catalysts are cooperatively working. It is anticipated that this minireview can make the promotion of advanced atomic‐level synergistic catalysts based on single‐atom sites.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"58 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208780","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}
The heterogeneous selective hydrogenation of nitrile butadiene rubber (NBR) is an efficient method to generate high value‐added hydrogenated NBR. Nevertheless, the inherent large molecular size and high spatial hindrance of polymers lead to poor activity and metal loss. Herein, we report a simple support ammonia pretreatment strategy for the synthesis of efficient N‐doped Pd catalyst and applied for the NBR hydrogenation. The results reveal that N doping enhances electrons transfer from the support to Pd more effectively than oxygen‐rich vacancy carrier, thereby substantially enhancing the electron cloud density and stability of the Pd sites. The formation of more electron‐rich Pd sites not only significantly enhances the adsorption‐activation ability of C=C and H2, but also lowers the apparent activation energy of the reaction. As a result, the Pd/N‐TiO2‐R demonstrates best activity with a hydrogenation degree (HD) of 98% and a TOF value of 335 h‐1, significantly higher than that of Pd/TiO2‐R (HD=83%, 282 h‐1) and Pd/TiO2 (HD=74%, 204 h‐1). This strategy will provide new inspiration to improve the activity and stability of Pd/TiO2 catalysts for the hydrogenation of unsaturated polymers.
{"title":"Regulating the Electronic Structure of Pd Nanoparticles on NH3‐pretreated Nano‐flake TiO2 for Efficient Hydrogenation of Nitrile Butadiene Rubber","authors":"Shidong Wang, Benwei Fan, Bingqing Ge, Hongwei Zhang, Cejun Hu, Qinyan Cui, Xiaojun Bao, Pei Yuan","doi":"10.1002/cctc.202401226","DOIUrl":"https://doi.org/10.1002/cctc.202401226","url":null,"abstract":"The heterogeneous selective hydrogenation of nitrile butadiene rubber (NBR) is an efficient method to generate high value‐added hydrogenated NBR. Nevertheless, the inherent large molecular size and high spatial hindrance of polymers lead to poor activity and metal loss. Herein, we report a simple support ammonia pretreatment strategy for the synthesis of efficient N‐doped Pd catalyst and applied for the NBR hydrogenation. The results reveal that N doping enhances electrons transfer from the support to Pd more effectively than oxygen‐rich vacancy carrier, thereby substantially enhancing the electron cloud density and stability of the Pd sites. The formation of more electron‐rich Pd sites not only significantly enhances the adsorption‐activation ability of C=C and H2, but also lowers the apparent activation energy of the reaction. As a result, the Pd/N‐TiO2‐R demonstrates best activity with a hydrogenation degree (HD) of 98% and a TOF value of 335 h‐1, significantly higher than that of Pd/TiO2‐R (HD=83%, 282 h‐1) and Pd/TiO2 (HD=74%, 204 h‐1). This strategy will provide new inspiration to improve the activity and stability of Pd/TiO2 catalysts for the hydrogenation of unsaturated polymers.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"60 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208781","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}
The high value‐added utilization of the fluorinated silica slag (FSS) waste, an associated by‐product of the anhydrous HF production from the accompanying fluorine resources in phosphate ore, is of great importance, but it remains a challenge. In this work, the Mg modified and unmodified Hβ zeolites from FSS waste were successfully prepared by a green dry gel conversion crystallization method with tetraethylammonium hydroxide (TEAOH) as a structure‐directing agent (SDA). The in situ Mg modified Hβ zeolite (Mg‐Hβ) shows much superior catalytic performance to unmodified (Hβ) and post Mg‐modified Hβ (Mg/Hβ) zeolites for acetylation of 2‐methoxynaphthalene (2‐MN) to 6‐acetyl‐2‐methoxynaphthalene (2,6‐AcMN), and the 40.2% of conversion for 2‐MN with 66.3% of selectivity for 2,6‐AcMN were achieved, ascribed to the high amount of B acidic sites and the promoted shape‐selective catalysis effect by higher surface area and volume of micropores. This work not only opens a new avenue for the high value‐added utilization of fluorinated silica slag waste, but also generates an efficient solid acid catalyst for the clean production of 2,6‐AcMN through the acetylation of 2‐MN with acetic anhydride.
{"title":"Modified H‐BEA Zeolites from Fluorinated Silica Slag Waste by Dry Gel Conversion Method for Shape‐Selective Acylation of 2‐Methoxynaphthalene","authors":"Xiao Wang, Zhongkui Zhao","doi":"10.1002/cctc.202401381","DOIUrl":"https://doi.org/10.1002/cctc.202401381","url":null,"abstract":"The high value‐added utilization of the fluorinated silica slag (FSS) waste, an associated by‐product of the anhydrous HF production from the accompanying fluorine resources in phosphate ore, is of great importance, but it remains a challenge. In this work, the Mg modified and unmodified Hβ zeolites from FSS waste were successfully prepared by a green dry gel conversion crystallization method with tetraethylammonium hydroxide (TEAOH) as a structure‐directing agent (SDA). The in situ Mg modified Hβ zeolite (Mg‐Hβ) shows much superior catalytic performance to unmodified (Hβ) and post Mg‐modified Hβ (Mg/Hβ) zeolites for acetylation of 2‐methoxynaphthalene (2‐MN) to 6‐acetyl‐2‐methoxynaphthalene (2,6‐AcMN), and the 40.2% of conversion for 2‐MN with 66.3% of selectivity for 2,6‐AcMN were achieved, ascribed to the high amount of B acidic sites and the promoted shape‐selective catalysis effect by higher surface area and volume of micropores. This work not only opens a new avenue for the high value‐added utilization of fluorinated silica slag waste, but also generates an efficient solid acid catalyst for the clean production of 2,6‐AcMN through the acetylation of 2‐MN with acetic anhydride.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"25 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208790","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}
CO2 electrochemical reduction (CO2ER) powered by renewable electricity is critical for transitioning to a carbon‐neutral society by transforming CO2 into essential commodities and fuels. The formation of multi‐carbon compounds through C‐C coupling reactions is crucial due to their high energy density and broad industrial uses. Traditionally, C‐C coupling was believed to occur through the reaction of *CO (surface‐bound CO) with *C1 intermediates (surface‐bound hydrocarbons with one carbon atom produced during CO2ER). In this study, we used DFT calculations combined with a constant electrode potential model to discover a preference for CO2 + *C1 over conventional *CO + *C1 coupling on three commonly observed copper surfaces including Cu(111), Cu(110), and Cu(100). This result demonstrates that CO2 is a more efficient carbon source than *CO for coupling with *C1. Among the nine *C1 species investigated, *CHO, *CHOH, *C, *CH, and *CH2 show greater reactivity towards CO2 + *C1 couplings on all the surfaces. Thus, enhancing CO2ER efficiency necessitates increasing the surface concentrations of these five *C1 intermediates, and several strategies have been proposed to accomplish this goal.
{"title":"Influence of Copper Surfaces on CO2 vs. CO C‐C Coupling Efficiency","authors":"Wen-Yu Lin, Zong-Xian Chen, Ting-You Wu, Hong-Wei Lin, Haocheng Xiong, Wei-Sen Chen, Qi Lu, Mu-Jeng Cheng","doi":"10.1002/cctc.202400983","DOIUrl":"https://doi.org/10.1002/cctc.202400983","url":null,"abstract":"CO2 electrochemical reduction (CO2ER) powered by renewable electricity is critical for transitioning to a carbon‐neutral society by transforming CO2 into essential commodities and fuels. The formation of multi‐carbon compounds through C‐C coupling reactions is crucial due to their high energy density and broad industrial uses. Traditionally, C‐C coupling was believed to occur through the reaction of *CO (surface‐bound CO) with *C1 intermediates (surface‐bound hydrocarbons with one carbon atom produced during CO2ER). In this study, we used DFT calculations combined with a constant electrode potential model to discover a preference for CO2 + *C1 over conventional *CO + *C1 coupling on three commonly observed copper surfaces including Cu(111), Cu(110), and Cu(100). This result demonstrates that CO2 is a more efficient carbon source than *CO for coupling with *C1. Among the nine *C1 species investigated, *CHO, *CHOH, *C, *CH, and *CH2 show greater reactivity towards CO2 + *C1 couplings on all the surfaces. Thus, enhancing CO2ER efficiency necessitates increasing the surface concentrations of these five *C1 intermediates, and several strategies have been proposed to accomplish this goal.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"73 3 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208782","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}
Covalent organic frameworks (COFs) incorporating metal are attractive alternatives for metal-catalyzed organic transformations. For effective metal incorporation in COF a favorable ligand environment is required. Pyridine and hydrazone units can provide effective binding sites for transition metals. The major challenge in synthesizing hydrazone-linked COFs is the inherent flexibility of the linker, causing differences in lengths and orientations during solvothermal synthesis. We demonstrate that incorporation of enol form in the framework facilitates non-covalent interactions such as hydrogen bonding, reduces degrees of freedom and enhances rigidity. Here, we synthesized TFP-PyHz COF utilizing 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde (TFP) and pyridine-2,6-dicarbohydrazide. Enol form in the framework was confirmed by comparing the IR and 13C solid-state NMR spectra of TFP-PyHz with its model compound. The presence of this enol form also facilitates the incorporation of Cu2+ through post-modification as confirmed by IR and XPS analysis of postmodified Cu-TFP-PyHz. The copper-incorporated material Cu-TFP-PyHz is utilized as a heterogeneous catalyst for copper-catalyzed click reactions, enabling the synthesis of 1,4-triazoles.
{"title":"Copper Incorporated Covalent Organic Framework As A Heterogeneous Catalyst For CuAAC Reaction","authors":"Mohit Mohit, K R Justin Thomas","doi":"10.1002/cctc.202401378","DOIUrl":"https://doi.org/10.1002/cctc.202401378","url":null,"abstract":"Covalent organic frameworks (COFs) incorporating metal are attractive alternatives for metal-catalyzed organic transformations. For effective metal incorporation in COF a favorable ligand environment is required. Pyridine and hydrazone units can provide effective binding sites for transition metals. The major challenge in synthesizing hydrazone-linked COFs is the inherent flexibility of the linker, causing differences in lengths and orientations during solvothermal synthesis. We demonstrate that incorporation of enol form in the framework facilitates non-covalent interactions such as hydrogen bonding, reduces degrees of freedom and enhances rigidity. Here, we synthesized TFP-PyHz COF utilizing 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde (TFP) and pyridine-2,6-dicarbohydrazide. Enol form in the framework was confirmed by comparing the IR and 13C solid-state NMR spectra of TFP-PyHz with its model compound. The presence of this enol form also facilitates the incorporation of Cu2+ through post-modification as confirmed by IR and XPS analysis of postmodified Cu-TFP-PyHz. The copper-incorporated material Cu-TFP-PyHz is utilized as a heterogeneous catalyst for copper-catalyzed click reactions, enabling the synthesis of 1,4-triazoles.","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"47 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208784","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}
The much‐needed global shift from fossil fuels to sustainable energy is driving significant attention towards hydrogen (H2) as a promising alternative. Proton reduction, a process central to H2 production, is a key area of research for this transition. Naturally‐occurring [FeFe] and [NiFe]‐hydrogenase enzymes play vital roles in the reversible production and oxidation of H2. These enzymes feature a proton‐relay unit comprising of pendant amine and thiol groups in the secondary coordination sphere at the active site. This unit accelerates the rate of H2 production/oxidation, making it a focal point for scientific exploration. Efforts are concentrated on mimicking the active sites of these enzymes both structurally and functionally. In this pursuit, many synthetic transition metal complexes with proton‐responsive units at the secondary coordination sphere of the active site mimic the enzyme's behavior. These units facilitate intramolecular metal‐hydride (M–H) generation and H2‐elimination via H+/H– coupling, leveraging the proton from the pendant functional group and the hydride from the M–H intermediate. This review delves into electrocatalysts featuring pendant proton‐responsive units and their roles in the electrochemical hydrogen evolution reaction (eHER).
{"title":"The Key Role of Proton‐Responsive Groups in Electrochemical Hydrogen Evolution Reaction","authors":"Sanajit Kumar Mandal, Saswati Ray, Joyanta Choudhury","doi":"10.1002/cctc.202401149","DOIUrl":"https://doi.org/10.1002/cctc.202401149","url":null,"abstract":"The much‐needed global shift from fossil fuels to sustainable energy is driving significant attention towards hydrogen (H2) as a promising alternative. Proton reduction, a process central to H2 production, is a key area of research for this transition. Naturally‐occurring [FeFe] and [NiFe]‐hydrogenase enzymes play vital roles in the reversible production and oxidation of H2. These enzymes feature a proton‐relay unit comprising of pendant amine and thiol groups in the secondary coordination sphere at the active site. This unit accelerates the rate of H2 production/oxidation, making it a focal point for scientific exploration. Efforts are concentrated on mimicking the active sites of these enzymes both structurally and functionally. In this pursuit, many synthetic transition metal complexes with proton‐responsive units at the secondary coordination sphere of the active site mimic the enzyme's behavior. These units facilitate intramolecular metal‐hydride (M–H) generation and H2‐elimination via H+/H– coupling, leveraging the proton from the pendant functional group and the hydride from the M–H intermediate. This review delves into electrocatalysts featuring pendant proton‐responsive units and their roles in the electrochemical hydrogen evolution reaction (eHER).","PeriodicalId":141,"journal":{"name":"ChemCatChem","volume":"169 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208788","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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