Pub Date : 2024-11-06DOI: 10.1016/j.checat.2024.101166
Izak Minnie, Hyunjik K. Kim, John Flake, Dongxia Liu
Taking advantage of the potentially low-cost and environmentally friendly nature of renewable energy sources like wind and photovoltaics has long been the aim of the CO2 electrolysis field. However, there have been sparse reports on the economic and performance implications of coupling these two systems. In this perspective, we present lessons that can be taken from work done in water electrolysis, summarize the progress that has been made in coupling electrochemical CO2 reduction systems to intermittent renewable energy sources, and perform a brief economic analysis on energy versus product storage in intermittent systems. Finally, we recommend future research directions, including rigorous studies on the effects of dynamic operation on electrolyzer components, strategies for integrating with continuous downstream processes, synergistic post-product processing via electrification technologies, and leveraging of artificial intelligence and automation to mitigate the unpredictability of CO₂ electrolysis.
{"title":"Intermittent CO2 electrolysis needs its time in the sun","authors":"Izak Minnie, Hyunjik K. Kim, John Flake, Dongxia Liu","doi":"10.1016/j.checat.2024.101166","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101166","url":null,"abstract":"Taking advantage of the potentially low-cost and environmentally friendly nature of renewable energy sources like wind and photovoltaics has long been the aim of the CO<sub>2</sub> electrolysis field. However, there have been sparse reports on the economic and performance implications of coupling these two systems. In this perspective, we present lessons that can be taken from work done in water electrolysis, summarize the progress that has been made in coupling electrochemical CO<sub>2</sub> reduction systems to intermittent renewable energy sources, and perform a brief economic analysis on energy versus product storage in intermittent systems. Finally, we recommend future research directions, including rigorous studies on the effects of dynamic operation on electrolyzer components, strategies for integrating with continuous downstream processes, synergistic post-product processing via electrification technologies, and leveraging of artificial intelligence and automation to mitigate the unpredictability of CO₂ electrolysis.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photochemical water oxidation in the presence of a Ru(II) photosensitizer to form O2 is one of the most studied reactions in (photo)catalysis for both homogeneous and heterogeneous systems. In the present work, several Ru(II)-tris-diimine-type complexes with different ligands were used under a wide pH range (3.7–9.4) and over different transition-metal oxide (MOx) catalysts to reveal the factors that govern the O2 evolution activity. Most importantly, the results clarified that a certain “threshold” potential determines whether water oxidation can proceed and that this potential is related to the energy barrier for electron transfer from the MOx catalyst to the Ru(II) photosensitizer. The results of this work highlight that the potential of the electrons involved in the water oxidation on MOx catalysts can be estimated through the simple application of a photochemical reaction, which will be a useful measure for assessing the water oxidation activity of suspended nanoparticle catalysts.
在 Ru(II) 光敏剂存在下进行光化学水氧化生成 O2 是研究最多的均相和异相系统（光）催化反应之一。在本研究中，研究人员在较宽的 pH 值范围（3.7-9.4）内，在不同的过渡金属氧化物（MOx）催化剂上使用了几种具有不同配体的 Ru(II)-tris-diimine 型配合物，以揭示影响 O2 演化活性的因素。最重要的是，研究结果明确了一个特定的 "阈值 "电位决定了水氧化能否进行，而这个电位与电子从 MOx 催化剂转移到 Ru(II) 光敏剂的能量障碍有关。这项工作的结果突出表明，可以通过简单的光化学反应来估算参与 MOx 催化剂上水氧化作用的电子的电位，这将是评估悬浮纳米粒子催化剂水氧化活性的有用指标。
{"title":"Discovery of the threshold potential that triggers photochemical water oxidation with Ru(II) photosensitizers and MOx catalysts","authors":"Megumi Okazaki, Yasuomi Yamazaki, Daling Lu, Shunsuke Nozawa, Osamu Ishitani, Kazuhiko Maeda","doi":"10.1016/j.checat.2024.101167","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101167","url":null,"abstract":"Photochemical water oxidation in the presence of a Ru(II) photosensitizer to form O<sub>2</sub> is one of the most studied reactions in (photo)catalysis for both homogeneous and heterogeneous systems. In the present work, several Ru(II)-tris-diimine-type complexes with different ligands were used under a wide pH range (3.7–9.4) and over different transition-metal oxide (MO<sub><em>x</em></sub>) catalysts to reveal the factors that govern the O<sub>2</sub> evolution activity. Most importantly, the results clarified that a certain “threshold” potential determines whether water oxidation can proceed and that this potential is related to the energy barrier for electron transfer from the MO<sub><em>x</em></sub> catalyst to the Ru(II) photosensitizer. The results of this work highlight that the potential of the electrons involved in the water oxidation on MO<sub><em>x</em></sub> catalysts can be estimated through the simple application of a photochemical reaction, which will be a useful measure for assessing the water oxidation activity of suspended nanoparticle catalysts.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1016/j.checat.2024.101159
Alexis K. Day, Mehdi Abdellaoui, Michèle Soleilhavoup, Guy Bertrand
Over the last three decades, the highly tunable properties of N-heterocyclic carbenes (NHCs) and other stable singlet carbenes have led to a variety of applications. This perspective shows a novel facet of carbenes—i.e., their reductive properties—that allows them to function as catalysts in single-electron transfer (SET) reactions. The isolation and even the spectroscopic characterization of a singly oxidized carbene have yet to be done, but these species readily abstract hydrogen atoms while giving back the carbene conjugate acid, which behaves as the resting state of catalytic cycles. In sharp contrast, a doubly oxidized carbene has been isolated, and there is a strong likelihood that many other carbene dications will be isolated. Their first Lewis acidity is very high, suggesting possible applications in Lewis acid catalysis.
{"title":"Singly and doubly oxidized carbenes and their applications in catalysis","authors":"Alexis K. Day, Mehdi Abdellaoui, Michèle Soleilhavoup, Guy Bertrand","doi":"10.1016/j.checat.2024.101159","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101159","url":null,"abstract":"Over the last three decades, the highly tunable properties of N-heterocyclic carbenes (NHCs) and other stable singlet carbenes have led to a variety of applications. This perspective shows a novel facet of carbenes—i.e., their reductive properties—that allows them to function as catalysts in single-electron transfer (SET) reactions. The isolation and even the spectroscopic characterization of a singly oxidized carbene have yet to be done, but these species readily abstract hydrogen atoms while giving back the carbene conjugate acid, which behaves as the resting state of catalytic cycles. In sharp contrast, a doubly oxidized carbene has been isolated, and there is a strong likelihood that many other carbene dications will be isolated. Their first Lewis acidity is very high, suggesting possible applications in Lewis acid catalysis.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.checat.2024.101165
Ivan Surin, Qingxin Yang, Frank Krumeich, Mikhail Agrachev, Tatiana Otroshchenko, Vita A. Kondratenko, Evgenii V. Kondratenko, Javier Pérez-Ramírez
Manganese (Mn) and chromium (Cr) catalysts supported on CeO2 enable direct ammonia oxidation to nitrous oxide, N2O, but the lack of synthesis-structure-performance relations hinders rational catalyst design. Herein, we generate a platform of CeO2-supported Mn and Cr catalysts, systematically varying the metal nanostructure from single atoms to nanoparticles, and the carrier redox properties, as confirmed by advanced characterization methods. Surface reducibility of CeO2 emerges as a general descriptor, controlling N2O productivity. Conversely, structure sensitivity is metal specific, with Mn-based systems achieving high N2O selectivity in single-atom and nanoparticle forms, while the selectivity of Cr-based systems is dependent on metal dispersion. In situ UV-visible (UV-vis), steady-state, and transient kinetic studies unveil the ability of redox-active MnOx to synergize with CeO2 and enhance oxygen transport for the reaction following a Mars-van Krevelen mechanism. This work provides fundamental insights into the role and function of each catalyst component and guidelines for the development of improved N2O synthesis catalysts.
{"title":"The role of metal nanostructure in ceria-supported catalysts for ammonia oxidation to nitrous oxide","authors":"Ivan Surin, Qingxin Yang, Frank Krumeich, Mikhail Agrachev, Tatiana Otroshchenko, Vita A. Kondratenko, Evgenii V. Kondratenko, Javier Pérez-Ramírez","doi":"10.1016/j.checat.2024.101165","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101165","url":null,"abstract":"Manganese (Mn) and chromium (Cr) catalysts supported on CeO<sub>2</sub> enable direct ammonia oxidation to nitrous oxide, N<sub>2</sub>O, but the lack of synthesis-structure-performance relations hinders rational catalyst design. Herein, we generate a platform of CeO<sub>2</sub>-supported Mn and Cr catalysts, systematically varying the metal nanostructure from single atoms to nanoparticles, and the carrier redox properties, as confirmed by advanced characterization methods. Surface reducibility of CeO<sub>2</sub> emerges as a general descriptor, controlling N<sub>2</sub>O productivity. Conversely, structure sensitivity is metal specific, with Mn-based systems achieving high N<sub>2</sub>O selectivity in single-atom and nanoparticle forms, while the selectivity of Cr-based systems is dependent on metal dispersion. <em>In situ</em> UV-visible (UV-vis), steady-state, and transient kinetic studies unveil the ability of redox-active MnO<sub><em>x</em></sub> to synergize with CeO<sub>2</sub> and enhance oxygen transport for the reaction following a Mars-van Krevelen mechanism. This work provides fundamental insights into the role and function of each catalyst component and guidelines for the development of improved N<sub>2</sub>O synthesis catalysts.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.checat.2024.101164
Isaac Kojo Seim, Manjeet Chhetri, John-Paul Jones, Ming Yang
Catalysts research for electrocatalytic CO2 reduction reactions (CO2R) has undergone rapid growth in the last decade. Single-atom alloy catalysts (SAAs) featuring atomically dispersed metal dopants on host metal surfaces have shown promises in boosting CO2R yield by optimizing the structure and synergy of the catalytic metals at the atomic scale. Despite the exciting development of SAAs for CO2R in fundamental science, dedicated studies for its engineering implementation have been absent. We use this perspective to discuss our non-exhaustive engineering considerations for implementing SAAs for CO2R. The perspective starts with a brief overview of the current research status for SAAs in CO2R, followed by focal points on structure uncertainties associated with catalyst manufacturing, catalyst layer degradation during reaction, and possibilities for SAAs to mitigate the salt precipitation issue at the device level. We hope our opinions will engage increasing attention toward the engineering catalysis research for applying SAAs to CO2R at scale.
近十年来，用于电催化二氧化碳还原反应（CO2R）的催化剂研究发展迅速。通过在原子尺度上优化催化金属的结构和协同作用，以主金属表面原子分散金属掺杂物为特征的单原子合金催化剂（SAAs）在提高 CO2R 产率方面展现出了广阔的前景。尽管用于 CO2R 的 SAAs 在基础科学方面取得了令人振奋的发展，但在工程实施方面却缺乏专门的研究。我们将从这个角度来讨论我们在实施用于 CO2R 的 SAA 过程中的非穷尽工程考虑因素。本视角首先简要概述了 SAA 在 CO2R 中的研究现状，然后重点讨论了与催化剂制造相关的结构不确定性、反应过程中的催化剂层降解以及 SAA 在设备层面缓解盐沉淀问题的可能性。我们希望我们的观点能吸引越来越多的人关注将 SAAs 大规模应用于 CO2R 的工程催化研究。
{"title":"Engineering intricacies of implementing single-atom alloy catalysts for low-temperature electrocatalytic CO2 reduction","authors":"Isaac Kojo Seim, Manjeet Chhetri, John-Paul Jones, Ming Yang","doi":"10.1016/j.checat.2024.101164","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101164","url":null,"abstract":"Catalysts research for electrocatalytic CO<sub>2</sub> reduction reactions (CO<sub>2</sub>R) has undergone rapid growth in the last decade. Single-atom alloy catalysts (SAAs) featuring atomically dispersed metal dopants on host metal surfaces have shown promises in boosting CO<sub>2</sub>R yield by optimizing the structure and synergy of the catalytic metals at the atomic scale. Despite the exciting development of SAAs for CO<sub>2</sub>R in fundamental science, dedicated studies for its engineering implementation have been absent. We use this perspective to discuss our non-exhaustive engineering considerations for implementing SAAs for CO<sub>2</sub>R. The perspective starts with a brief overview of the current research status for SAAs in CO<sub>2</sub>R, followed by focal points on structure uncertainties associated with catalyst manufacturing, catalyst layer degradation during reaction, and possibilities for SAAs to mitigate the salt precipitation issue at the device level. We hope our opinions will engage increasing attention toward the engineering catalysis research for applying SAAs to CO<sub>2</sub>R at scale.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-28DOI: 10.1016/j.checat.2024.101157
Mengjun Xiao, Qianbao Wu, Hongfei Liu, Xia Zheng, Lei Li, Wei Wang, Chunhua Cui
OH−/H2O-reactant discrimination for the oxygen evolution reaction (OER) is a critical but not well resolved issue. This has led to unreasonable activity comparisons, misinterpreted OER mechanisms, and ununified models for theoretical calculations regardless of the thermodynamic/kinetic difference between OH− and H2O oxidation. Here, we discriminate between OH− and H2O oxidation by tuning the interfacial OH− concentration. Combining OER kinetic analysis with in situ16OH−/H218O isotopic labeling-based differential electrochemical mass spectrometry, we examine the respective electrochemical oxidation behaviors between OH− and H2O oxidation. We find that OH− oxidation presents ∼550 mV lower onset potential relative to H2O oxidation and that Tafel plotting gives slopes of ∼50 mV dec−1 for OH− oxidation, which is substantially lower than those of ∼200 mV dec−1 for H2O oxidation on a model CoOOH catalyst. This work calls for the discrimination of OH−/H2O oxidation as the prerequisite for future OER activity evaluation and mechanism studies.
{"title":"Discrimination between OH− and H2O oxidation for oxygen evolution reaction","authors":"Mengjun Xiao, Qianbao Wu, Hongfei Liu, Xia Zheng, Lei Li, Wei Wang, Chunhua Cui","doi":"10.1016/j.checat.2024.101157","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101157","url":null,"abstract":"OH<sup><strong>−</strong></sup>/H<sub>2</sub>O-reactant discrimination for the oxygen evolution reaction (OER) is a critical but not well resolved issue. This has led to unreasonable activity comparisons, misinterpreted OER mechanisms, and ununified models for theoretical calculations regardless of the thermodynamic/kinetic difference between OH<sup><strong>−</strong></sup> and H<sub>2</sub>O oxidation. Here, we discriminate between OH<sup><strong>−</strong></sup> and H<sub>2</sub>O oxidation by tuning the interfacial OH<sup><strong>−</strong></sup> concentration. Combining OER kinetic analysis with <em>in situ</em> <sup>16</sup>OH<sup><strong>−</strong></sup>/H<sub>2</sub><sup>18</sup>O isotopic labeling-based differential electrochemical mass spectrometry, we examine the respective electrochemical oxidation behaviors between OH<sup><strong>−</strong></sup> and H<sub>2</sub>O oxidation. We find that OH<sup><strong>−</strong></sup> oxidation presents ∼550 mV lower onset potential relative to H<sub>2</sub>O oxidation and that Tafel plotting gives slopes of ∼50 mV dec<sup>−1</sup> for OH<sup><strong>−</strong></sup> oxidation, which is substantially lower than those of ∼200 mV dec<sup>−1</sup> for H<sub>2</sub>O oxidation on a model CoOOH catalyst. This work calls for the discrimination of OH<sup><strong>−</strong></sup>/H<sub>2</sub>O oxidation as the prerequisite for future OER activity evaluation and mechanism studies.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142519379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-25DOI: 10.1016/j.checat.2024.101163
Cheng Zhang, Shanliang Dong, Martin C. Dietl, Matthias Rudolph, Xinke Zhang, Kemiao Hong, Wei Yi, A. Stephen K. Hashmi, Xinfang Xu
The exploration of reactive intermediates, which enable chemo- and regioselective cycloaddition reactions for the expeditious construction of fused and/or bridged ring systems, continues to draw a great deal of interest from the synthetic community. Vinylcarbene species, which serve as 3-carbon building blocks, have been frequently used for the construction of (hetero)cyclic frameworks through the successive formation of multiple carbon–carbon and/or carbon–heteroatom bonds. Herein, we report a concise strategy for the catalytic generation of an exocyclic α-vinyl gold carbene species via a selective gold(I)-promoted azide-enyne cyclization process. Subsequently, practical and modular cycloadditions of these in-situ-formed intermediates with different types of partners were disclosed, producing a diverse array of fused and bridged pyrroles in high chemo-, regio-, and stereoselectivity.
{"title":"Practical and modular cycloadditions of in-situ formed exocyclic vinylcarbenes","authors":"Cheng Zhang, Shanliang Dong, Martin C. Dietl, Matthias Rudolph, Xinke Zhang, Kemiao Hong, Wei Yi, A. Stephen K. Hashmi, Xinfang Xu","doi":"10.1016/j.checat.2024.101163","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101163","url":null,"abstract":"The exploration of reactive intermediates, which enable chemo- and regioselective cycloaddition reactions for the expeditious construction of fused and/or bridged ring systems, continues to draw a great deal of interest from the synthetic community. Vinylcarbene species, which serve as 3-carbon building blocks, have been frequently used for the construction of (hetero)cyclic frameworks through the successive formation of multiple carbon–carbon and/or carbon–heteroatom bonds. Herein, we report a concise strategy for the catalytic generation of an exocyclic α-vinyl gold carbene species via a selective gold(I)-promoted azide-enyne cyclization process. Subsequently, practical and modular cycloadditions of these <em>in</em>-<em>situ</em>-formed intermediates with different types of partners were disclosed, producing a diverse array of fused and bridged pyrroles in high chemo-, regio-, and stereoselectivity.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-25DOI: 10.1016/j.checat.2024.101153
Wenchao Jiang, Chenwei Ni, Yejun Xiao, Yue Zhao, Chu Han, Xuan Wu, Chengbo Zhang, Haibo Chi, Rengui Li, Can Li
Although crystal facet engineering of semiconductor crystals has been demonstrated to be effective in particulate photocatalysts for solar energy conversion, it is imperative to rationally regulate the exposed crystal facets and their configurations to improve charge separation efficiency. In this study, focusing on visible-light-driven water oxidation photocatalyst lead chromate (PbCrO4), we find that a flux-assisted treatment enables the precise tuning of the hole-accumulating facets of anisotropic PbCrO4 crystal, transitioning the top surface from {−101} to {001} facets while preserving its spatial charge separation characteristics. Owing to the superior hole-accumulating property and water oxidation kinetics of the {001} facets, the resulting Flux-PbCrO4 crystals achieve a charge separation efficiency exceeding 75%, leading to a remarkable improvement in photocatalytic water oxidation activity. Further incorporation of cocatalysts onto the Flux-PbCrO4 crystals results in an apparent quantum efficiency of 18.5% at 500 nm for photocatalytic water oxidation.
{"title":"Boosting photocatalytic water oxidation on lead chromate through crystal facet engineering","authors":"Wenchao Jiang, Chenwei Ni, Yejun Xiao, Yue Zhao, Chu Han, Xuan Wu, Chengbo Zhang, Haibo Chi, Rengui Li, Can Li","doi":"10.1016/j.checat.2024.101153","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101153","url":null,"abstract":"Although crystal facet engineering of semiconductor crystals has been demonstrated to be effective in particulate photocatalysts for solar energy conversion, it is imperative to rationally regulate the exposed crystal facets and their configurations to improve charge separation efficiency. In this study, focusing on visible-light-driven water oxidation photocatalyst lead chromate (PbCrO<sub>4</sub>), we find that a flux-assisted treatment enables the precise tuning of the hole-accumulating facets of anisotropic PbCrO<sub>4</sub> crystal, transitioning the top surface from {−101} to {001} facets while preserving its spatial charge separation characteristics. Owing to the superior hole-accumulating property and water oxidation kinetics of the {001} facets, the resulting Flux-PbCrO<sub>4</sub> crystals achieve a charge separation efficiency exceeding 75%, leading to a remarkable improvement in photocatalytic water oxidation activity. Further incorporation of cocatalysts onto the Flux-PbCrO<sub>4</sub> crystals results in an apparent quantum efficiency of 18.5% at 500 nm for photocatalytic water oxidation.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.checat.2024.101160
Godwin A. Aleku, Florian Hollfelder
Imine reductases (IREDs) are invaluable catalysts for enantioselective imine reduction and reductive amination of carbonyl compounds. Their synthetic versatility is, however, limited by their substrate scope, and new IREDs are needed. Current IREDs are closely related to the initially characterized enzymes, as their discovery has been driven by sequence homology searches. Here, we demonstrate a functional genomics approach based on biosynthetic promiscuity, guided by the identification of C=N reducing enzymes acting on large, complex substrates in biosynthetic pathways. These substrate-promiscuous biocatalysts share low homology to existing IREDs and fall into distinct functional enzyme families, yet they catalyze the hydrogenation of non-native imines as well as the reductive amination of simple ketones. Venturing further into sequence space without the constraints of close homology, but instead guided by functional promiscuity, has thus led us to distinct, previously unrecognized and unexplored areas of sequence space for mining IREDs for synthesis.
{"title":"Expanding the repertoire of imine reductases by mining divergent biosynthetic pathways for promiscuous reactivity","authors":"Godwin A. Aleku, Florian Hollfelder","doi":"10.1016/j.checat.2024.101160","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101160","url":null,"abstract":"Imine reductases (IREDs) are invaluable catalysts for enantioselective imine reduction and reductive amination of carbonyl compounds. Their synthetic versatility is, however, limited by their substrate scope, and new IREDs are needed. Current IREDs are closely related to the initially characterized enzymes, as their discovery has been driven by sequence homology searches. Here, we demonstrate a <em>functional</em> genomics approach based on biosynthetic promiscuity, guided by the identification of C=N reducing enzymes acting on large, complex substrates in biosynthetic pathways. These substrate-promiscuous biocatalysts share low homology to existing IREDs and fall into distinct functional enzyme families, yet they catalyze the hydrogenation of non-native imines as well as the reductive amination of simple ketones. Venturing further into sequence space without the constraints of close homology, but instead guided by functional promiscuity, has thus led us to distinct, previously unrecognized and unexplored areas of sequence space for mining IREDs for synthesis.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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