Herein, a visible-light-induced umpolung strategy for reductive carboxylation of imines for synthesis of unnatural α-amino acids was disclosed. A reaction mechanism involving electron-donor–acceptor (EDA) complex formation between substrate and oxalate to furnish the desired products was proposed. Oxalic salt in situ generates CO2 radical anion (CO2•–) and carbon dioxide (CO2) as the key single-electron reductant and carbonyl (C1) source, respectively, during the transformation with or without photocatalyst.
{"title":"Photochemical Reductive Carboxylation of N-Benzoyl Imines with Oxalate Accelerated by Formation of EDA Complexes","authors":"Wen-Wen Liu, Pei Xu, Hui-Xian Jiang, Meng-Lei Li, Tian-Zi Hao, Yi-Qin Liu, Song-Lei Zhu, Kun-Xiao Zhang, Xu Zhu","doi":"10.1021/acscatal.4c02007","DOIUrl":"https://doi.org/10.1021/acscatal.4c02007","url":null,"abstract":"Herein, a visible-light-induced umpolung strategy for reductive carboxylation of imines for synthesis of unnatural α-amino acids was disclosed. A reaction mechanism involving electron-donor–acceptor (EDA) complex formation between substrate and oxalate to furnish the desired products was proposed. Oxalic salt in situ generates CO<sub>2</sub> radical anion (CO<sub>2</sub><sup>•–</sup>) and carbon dioxide (CO<sub>2</sub>) as the key single-electron reductant and carbonyl (C1) source, respectively, during the transformation with or without photocatalyst.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-20DOI: 10.1021/acscatal.4c02448
Yuanhong Lu, Qiao Chen, Yunlong Zhang, Yan Wei, Xiaohui Hou, Rui Huang, Dehui Deng
Replacing H2 with H2O as the hydrogen source for the water-involved selective hydrogenation of cinnamaldehyde to cinnamyl alcohol (WSHCC) is very attractive yet is underdeveloped by a much lower H2O conversion rate than H2. Here, we report the realization of a high-efficiency WSHCC process by a synergy of CO adsorption and H2O dissociation over a Au/α-MoC1–x boundary. It shows a specific molar rate of 60.86 mol molAu–1 h–1 to cinnamyl alcohol at 96 °C, which is nearly 12-fold that reported earlier, and maintains a high conversion of over 99% and a high selectivity of 77%. Mechanistic studies indicate that the Au/α-MoC1–x boundary accommodates atomically dispersed Auδ+ sites for adsorbing CO, vacating oxygen-covered α-MoC1–x and thereby creating isolated Mo sites for the preferred adsorption and hydrogenation of C═O bonds over that of C═C bonds. This provides a catalyst design strategy for high-efficiency C═O hydrogenation by water.
{"title":"Accelerating Semihydrogenation of Cinnamaldehyde by Water over a Au/α-MoC Catalyst","authors":"Yuanhong Lu, Qiao Chen, Yunlong Zhang, Yan Wei, Xiaohui Hou, Rui Huang, Dehui Deng","doi":"10.1021/acscatal.4c02448","DOIUrl":"https://doi.org/10.1021/acscatal.4c02448","url":null,"abstract":"Replacing H<sub>2</sub> with H<sub>2</sub>O as the hydrogen source for the water-involved selective hydrogenation of cinnamaldehyde to cinnamyl alcohol (WSHCC) is very attractive yet is underdeveloped by a much lower H<sub>2</sub>O conversion rate than H<sub>2</sub>. Here, we report the realization of a high-efficiency WSHCC process by a synergy of CO adsorption and H<sub>2</sub>O dissociation over a Au/α-MoC<sub>1–<i>x</i></sub> boundary. It shows a specific molar rate of 60.86 mol mol<sub>Au</sub><sup>–1</sup> h<sup>–1</sup> to cinnamyl alcohol at 96 °C, which is nearly 12-fold that reported earlier, and maintains a high conversion of over 99% and a high selectivity of 77%. Mechanistic studies indicate that the Au/α-MoC<sub>1–<i>x</i></sub> boundary accommodates atomically dispersed Au<sup>δ+</sup> sites for adsorbing CO, vacating oxygen-covered α-MoC<sub>1–<i>x</i></sub> and thereby creating isolated Mo sites for the preferred adsorption and hydrogenation of C═O bonds over that of C═C bonds. This provides a catalyst design strategy for high-efficiency C═O hydrogenation by water.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141435915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-20DOI: 10.1021/acscatal.4c01445
Miika Mattinen, Wei Chen, Rebecca A. Dawley, Marcel A. Verheijen, Emiel J. M. Hensen, W. M. M. Kessels, Ageeth A. Bol
Molybdenum sulfides (MoSx) in both crystalline and amorphous forms are promising earth-abundant electrocatalysts for hydrogen evolution reaction (HER) in acid. Plasma-enhanced atomic layer deposition was used to prepare thin films of both amorphous MoSx with adjustable S/Mo ratio (2.8–4.7) and crystalline MoS2 with tailored crystallinity, morphology, and electrical properties. All the amorphous MoSx films transform into highly HER-active amorphous MoS2 (overpotential 210–250 mV at 10 mA/cm2 in 0.5 M H2SO4) after electrochemical activation at approximately −0.3 V vs reversible hydrogen electrode. However, the initial film stoichiometry affects the structure and consequently the HER activity and stability. The material changes occurring during activation are studied using ex situ and quasi in situ X-ray photoelectron spectroscopy. Possible structures of as-deposited and activated catalysts are proposed. In contrast to amorphous MoSx, no changes in the structure of crystalline MoS2 catalysts are observed. The overpotentials of the crystalline films range from 300 to 520 mV at 10 mA/cm2, being the lowest for the most defective catalysts. This work provides a practical method for deposition of tailored MoSx HER electrocatalysts as well as new insights into their activity and structure.
晶态和非晶态硫化钼（MoSx）是酸中氢进化反应（HER）很有前途的富土电催化剂。等离子体增强原子层沉积技术可用于制备 S/Mo 比可调（2.8-4.7）的非晶态 MoSx 薄膜和具有定制结晶度、形态和电性能的晶体 MoS2 薄膜。所有无定形 MoSx 薄膜在大约 -0.3 V 对可逆氢电极进行电化学活化后，都会转化为具有高度氢转换活性的无定形 MoS2（在 0.5 M H2SO4 中 10 mA/cm2 的过电位为 210-250 mV）。然而，初始薄膜的化学计量会影响其结构，进而影响 HER 的活性和稳定性。我们使用原位和准原位 X 射线光电子能谱对活化过程中发生的材料变化进行了研究。提出了沉积和活化催化剂的可能结构。与无定形 MoSx 不同，晶体 MoS2 催化剂的结构没有发生变化。在 10 mA/cm2 的条件下，晶体薄膜的过电位在 300 至 520 mV 之间，其中缺陷最大的催化剂的过电位最低。这项工作为沉积量身定制的 MoSx HER 电催化剂提供了一种实用方法，并对其活性和结构有了新的认识。
{"title":"Structural Aspects of MoSx Prepared by Atomic Layer Deposition for Hydrogen Evolution Reaction","authors":"Miika Mattinen, Wei Chen, Rebecca A. Dawley, Marcel A. Verheijen, Emiel J. M. Hensen, W. M. M. Kessels, Ageeth A. Bol","doi":"10.1021/acscatal.4c01445","DOIUrl":"https://doi.org/10.1021/acscatal.4c01445","url":null,"abstract":"Molybdenum sulfides (MoS<sub><i>x</i></sub>) in both crystalline and amorphous forms are promising earth-abundant electrocatalysts for hydrogen evolution reaction (HER) in acid. Plasma-enhanced atomic layer deposition was used to prepare thin films of both amorphous MoS<sub><i>x</i></sub> with adjustable S/Mo ratio (2.8–4.7) and crystalline MoS<sub>2</sub> with tailored crystallinity, morphology, and electrical properties. All the amorphous MoS<sub><i>x</i></sub> films transform into highly HER-active amorphous MoS<sub>2</sub> (overpotential 210–250 mV at 10 mA/cm<sup>2</sup> in 0.5 M H<sub>2</sub>SO<sub>4</sub>) after electrochemical activation at approximately −0.3 V vs reversible hydrogen electrode. However, the initial film stoichiometry affects the structure and consequently the HER activity and stability. The material changes occurring during activation are studied using ex situ and quasi in situ X-ray photoelectron spectroscopy. Possible structures of as-deposited and activated catalysts are proposed. In contrast to amorphous MoS<sub><i>x</i></sub>, no changes in the structure of crystalline MoS<sub>2</sub> catalysts are observed. The overpotentials of the crystalline films range from 300 to 520 mV at 10 mA/cm<sup>2</sup>, being the lowest for the most defective catalysts. This work provides a practical method for deposition of tailored MoS<sub><i>x</i></sub> HER electrocatalysts as well as new insights into their activity and structure.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-20DOI: 10.1021/acscatal.4c02172
Kaiwei Liu, Boyang Zhang, Jiaming Zhang, Yao Xu, Jifang Zhang, Zihao Zhang, Ke Shi, Ningning Wang, Shanshan Chen, Guijun Ma
The Z-scheme system, integrating an oxygen evolution photocatalyst (OEP) with a hydrogen evolution photocatalyst (HEP), is an ideal strategy for photocatalytic overall water splitting (OWS), in which the development of an efficient OEP remains a challenge. Herein, the GaN:ZnO photocatalyst was synthesized by an ammonium halide-based process to perform a recorded apparent quantum yield of 30% at 420 nm for oxygen evolution from water. It made the GaN:ZnO a remarkable OEP for the construction of three distinct Z-scheme OWS systems, including an unbiased-photoelectrochemical sheet, direct collision, and redox-ion-mediated electron shuttle. The features and parameters of each Z-scheme system were discussed in relation to water splitting, and the most efficient one was established by employing [Fe(CN)6]3–/[Fe(CN)6]4– as an electron shuttle and SrTiO3:Rh as an HEP. This work not only provides a methodology for synthesizing an efficient GaN:ZnO photocatalyst but also highlights its great potential as an OEP applicable to constructing various Z-scheme OWS systems.
将氧进化光催化剂（OEP）与氢进化光催化剂（HEP）整合在一起的 Z 型体系是光催化整体水分离（OWS）的理想策略，而高效 OEP 的开发仍是一项挑战。本文采用基于卤化铵的工艺合成了 GaN:ZnO 光催化剂，在 420 纳米波长下实现了 30% 的表观量子产率，用于水的氧气进化。这使得 GaN:ZnO 成为构建三种不同 Z 方案 OWS 系统的理想 OEP，包括无偏光电化学片、直接碰撞和氧化还原离子介导的电子穿梭。讨论了每种 Z 型体系在水分离方面的特征和参数，并通过使用 [Fe(CN)6]3-/[Fe(CN)6]4- 作为电子穿梭器和 SrTiO3:Rh 作为 HEP，建立了最高效的 Z 型体系。这项工作不仅提供了一种合成高效 GaN:ZnO 光催化剂的方法，而且凸显了其作为一种 OEP 的巨大潜力，可用于构建各种 Z 型 OWS 系统。
{"title":"Synthesis of Highly Active GaN:ZnO Photocatalysts Applicable to Z-Scheme Overall Water Splitting Systems","authors":"Kaiwei Liu, Boyang Zhang, Jiaming Zhang, Yao Xu, Jifang Zhang, Zihao Zhang, Ke Shi, Ningning Wang, Shanshan Chen, Guijun Ma","doi":"10.1021/acscatal.4c02172","DOIUrl":"https://doi.org/10.1021/acscatal.4c02172","url":null,"abstract":"The Z-scheme system, integrating an oxygen evolution photocatalyst (OEP) with a hydrogen evolution photocatalyst (HEP), is an ideal strategy for photocatalytic overall water splitting (OWS), in which the development of an efficient OEP remains a challenge. Herein, the GaN:ZnO photocatalyst was synthesized by an ammonium halide-based process to perform a recorded apparent quantum yield of 30% at 420 nm for oxygen evolution from water. It made the GaN:ZnO a remarkable OEP for the construction of three distinct Z-scheme OWS systems, including an unbiased-photoelectrochemical sheet, direct collision, and redox-ion-mediated electron shuttle. The features and parameters of each Z-scheme system were discussed in relation to water splitting, and the most efficient one was established by employing [Fe(CN)<sub>6</sub>]<sup>3–</sup>/[Fe(CN)<sub>6</sub>]<sup>4–</sup> as an electron shuttle and SrTiO<sub>3</sub>:Rh as an HEP. This work not only provides a methodology for synthesizing an efficient GaN:ZnO photocatalyst but also highlights its great potential as an OEP applicable to constructing various Z-scheme OWS systems.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141435920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-20DOI: 10.1021/acscatal.4c01419
Wenqiang Yang, Kareem E. Abdelfatah, Subrata Kumar Kundu, Biplab Rajbanshi, Gabriel A. Terejanu, Andreas Heyden
The complex reaction network of catalytic biomass conversions often involves hundreds of surface intermediates and thousands of reaction steps, greatly hindering the rational design of metal catalysts for these conversions. Here, we present a framework of machine learning (ML)-accelerated first-principles studies for the hydrodeoxygenation (HDO) of propanoic acid over transition metal surfaces. The microkinetic model (MKM) is initially parametrized by ML-predicted energies and iteratively improved by identifying the rate-determining species and steps (RDS), computing their energies by density functional theory (DFT), and reparameterizing the MKM until all the RDS are computed by DFT. The Gaussian process (GP) model performs significantly better than the linear ridge regression model for predicting both the adsorption free energies and transition state free energies. Parameterized with energies from the GP model, only 5–20% of the full reaction network has to be computed by DFT for the MKM to possess DFT-level accuracy for the TOF and dominant reaction pathway. While the linear ridge regression model performs worse than the GP model, its performance is greatly improved when only transition states are predicted by the regression model and adsorption energies are computed by DFT. Overall, we find that a high accuracy in adsorption free energies is more important for a reliable MKM than a high accuracy in TS free energies. Finally, based on the GP model with GOH and GCHCHCO as catalyst descriptors, we build two-dimensional volcano plots in activity and selectivity that can help design promising alloy catalysts for HDO reactions of organic acids.
催化生物质转化的复杂反应网络通常涉及数百个表面中间体和数千个反应步骤，这极大地阻碍了用于这些转化的金属催化剂的合理设计。在此，我们提出了一个机器学习（ML）加速的第一原理研究框架，用于过渡金属表面丙酸的加氢脱氧反应（HDO）。微动力学模型（MKM）最初由 ML 预测的能量参数化，然后通过识别决定速率的物种和步骤（RDS）、用密度泛函理论（DFT）计算它们的能量以及重新参数化 MKM 直到所有的 RDS 都用 DFT 计算出来来迭代改进。在预测吸附自由能和过渡态自由能方面，高斯过程（GP）模型的表现明显优于线性回归模型。利用 GP 模型的能量参数，只需通过 DFT 计算 5-20% 的完整反应网络，MKM 就能在 TOF 和主要反应途径方面达到 DFT 水平的精度。虽然线性脊回归模型的性能比 GP 模型差，但当回归模型只预测过渡态而用 DFT 计算吸附能时，其性能就会大大提高。总之，我们发现，对于可靠的 MKM 而言，吸附自由能的高精度比 TS 自由能的高精度更为重要。最后，基于以 GOH 和 GCHCHCO 为催化剂描述符的 GP 模型，我们绘制了活性和选择性的二维火山图，这有助于设计有前途的合金催化剂，用于有机酸的 HDO 反应。
{"title":"Machine Learning Accelerated First-Principles Study of the Hydrodeoxygenation of Propanoic Acid","authors":"Wenqiang Yang, Kareem E. Abdelfatah, Subrata Kumar Kundu, Biplab Rajbanshi, Gabriel A. Terejanu, Andreas Heyden","doi":"10.1021/acscatal.4c01419","DOIUrl":"https://doi.org/10.1021/acscatal.4c01419","url":null,"abstract":"The complex reaction network of catalytic biomass conversions often involves hundreds of surface intermediates and thousands of reaction steps, greatly hindering the rational design of metal catalysts for these conversions. Here, we present a framework of machine learning (ML)-accelerated first-principles studies for the hydrodeoxygenation (HDO) of propanoic acid over transition metal surfaces. The microkinetic model (MKM) is initially parametrized by ML-predicted energies and iteratively improved by identifying the rate-determining species and steps (RDS), computing their energies by density functional theory (DFT), and reparameterizing the MKM until all the RDS are computed by DFT. The Gaussian process (GP) model performs significantly better than the linear ridge regression model for predicting both the adsorption free energies and transition state free energies. Parameterized with energies from the GP model, only 5–20% of the full reaction network has to be computed by DFT for the MKM to possess DFT-level accuracy for the TOF and dominant reaction pathway. While the linear ridge regression model performs worse than the GP model, its performance is greatly improved when only transition states are predicted by the regression model and adsorption energies are computed by DFT. Overall, we find that a high accuracy in adsorption free energies is more important for a reliable MKM than a high accuracy in TS free energies. Finally, based on the GP model with G<sub>OH</sub> and G<sub>CHCHCO</sub> as catalyst descriptors, we build two-dimensional volcano plots in activity and selectivity that can help design promising alloy catalysts for HDO reactions of organic acids.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-20DOI: 10.1021/acscatal.4c01749
Zhuoyan Lv, Leilei Kang, Xiaoli Pan, Yang Su, Hua Wang, Lin Li, Xiao Yan Liu, Aiqin Wang, Tao Zhang
Controlling the precise placement of active metals on supports is highly desirable yet challenging, which governs both the reaction pathway and the ultimate outcomes of catalytic reactions. Herein, the Cu species are positioned to the Lewis acidic sites created by the ultrahigh-temperature calcination of TiO2, where the atomic structures of the Lewis acids are identified as five-coordinated Ti4+ cations bound to three-coordinated O2– anions (Lβ sites) by in situ characterizations. Owing to the robust chemical affinity, CuOx manifests itself as a nanopatch. The Cu/TiO2 catalyst without any modifications exhibits a propylene oxide (PO) formation rate of 44 mmol gCu–1 h–1 for direct epoxidation of propylene using molecular oxygen (DEP). The PO yield on Cu/TiO2 can be efficiently correlated with the quantity of the decreased Lewis acids, which demonstrates that the intimated interaction between the Cu species and Lewis acids should be responsible for PO production. Furthermore, density functional theory calculations suggest that Cu+ in the Ti–O–Cu interface formed at the Lβ sites is the active site of the DEP reaction, with the aid of the adjacent Cu atom. This study provides a Cu-based catalyst for the DEP reaction.
控制活性金属在支持物上的精确定位是非常理想的，但也是极具挑战性的，因为这关系到反应路径和催化反应的最终结果。在本文中，Cu 物种被置于 TiO2 超高温煅烧产生的路易斯酸位点上，通过原位表征，确定了路易斯酸的原子结构为五配位 Ti4+ 阳离子与三配位 O2- 阴离子结合（Lβ 位点）。由于强大的化学亲和力，CuOx 表现为纳米斑块。在使用分子氧（DEP）对丙烯进行直接环氧化反应时，未经任何改性的 Cu/TiO2 催化剂显示出 44 mmol gCu-1 h-1 的环氧丙烷（PO）形成率。Cu/TiO2 上的环氧丙烷产量与路易斯酸减少的数量呈有效的相关性，这表明 Cu 物种与路易斯酸之间的相互作用是产生环氧丙烷的原因。此外，密度泛函理论计算表明，在 Lβ 位点上形成的 Ti-O-Cu 界面中的 Cu+ 是 DEP 反应的活性位点，相邻的 Cu 原子起着辅助作用。这项研究为 DEP 反应提供了一种铜基催化剂。
{"title":"CuOx Nanopatches Positioned at Lewis Acidic Sites of TiO2 for Propylene Epoxidation Using Molecular Oxygen","authors":"Zhuoyan Lv, Leilei Kang, Xiaoli Pan, Yang Su, Hua Wang, Lin Li, Xiao Yan Liu, Aiqin Wang, Tao Zhang","doi":"10.1021/acscatal.4c01749","DOIUrl":"https://doi.org/10.1021/acscatal.4c01749","url":null,"abstract":"Controlling the precise placement of active metals on supports is highly desirable yet challenging, which governs both the reaction pathway and the ultimate outcomes of catalytic reactions. Herein, the Cu species are positioned to the Lewis acidic sites created by the ultrahigh-temperature calcination of TiO<sub>2</sub>, where the atomic structures of the Lewis acids are identified as five-coordinated Ti<sup>4+</sup> cations bound to three-coordinated O<sup>2–</sup> anions (L<sub>β</sub> sites) by <i>in situ</i> characterizations. Owing to the robust chemical affinity, CuO<sub><i>x</i></sub> manifests itself as a nanopatch. The Cu/TiO<sub>2</sub> catalyst without any modifications exhibits a propylene oxide (PO) formation rate of 44 mmol g<sub>Cu</sub><sup>–1</sup> h<sup>–1</sup> for direct epoxidation of propylene using molecular oxygen (DEP). The PO yield on Cu/TiO<sub>2</sub> can be efficiently correlated with the quantity of the decreased Lewis acids, which demonstrates that the intimated interaction between the Cu species and Lewis acids should be responsible for PO production. Furthermore, density functional theory calculations suggest that Cu<sup>+</sup> in the Ti–O–Cu interface formed at the L<sub>β</sub> sites is the active site of the DEP reaction, with the aid of the adjacent Cu atom. This study provides a Cu-based catalyst for the DEP reaction.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Selectivity control of supported metal catalysts, which are most widely utilized in the field of heterogeneous catalysis, is of great scientific significance to obtaining the desired chemical product in a multipath reaction but has remained a grand challenging issue. In this work, we demonstrate that the selectivity of CO2 hydrogenation from CH4 to CO can be tuned by a robust and unique support doping strategy by changing the reduction activity of H species over M/Ce1–xPrxO2−δ (M = Ru, Rh) in which metal (M) nanoclusters showed the same existence form on differently doped ceria nanorod supports. The CH4 selectivity of the catalyst decreased with an increase in the Pr content in the support. The selectivity of CH4 on Ru/CeO2 was higher than 90%, while on Ru/Ce0.2Pr0.8O2−δ, the selectivity of CO reached 80%. A variety of techniques, including steady-state isotope transient kinetic analysis (SSITKA) type in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)–mass spectrum (MS), temperature-programmed desorption (TPD) and temperature-programmed surface reaction (TPSR), had been applied in this work to analyze the structure–activity relationship between the doping of Pr and the selectivity of the CO2 hydrogenation reaction. Ru sites were not directly involved in the hydrogenation of carbon-containing intermediate species (including bicarbonate and formate) during the CO2 hydrogenation reaction. The active H species on the support sites, which are incorporated in RE3+–OH, directly contacted and reacted with the carbon-containing intermediate species. The introduction of Pr in the support weakened the reducing ability of the support, thus decreasing the reducing ability of H species on the surface of the catalyst, which further hindered the conversion of formate into CH4, resulting in the declined CH4 selectivity. Our study clearly revealed the important role of support in the CO2 hydrogenation reaction and proposed a strategy to modulate the reaction selectivity via support doping. By changing the redox performance of the support, the activity of H species on the support can be adjusted. Thus, the conversion of important reaction intermediates (such as formate) can be affected, so as to achieve precise regulation of the reaction products. We have provided a broader perspective for the selective catalyst design of heterogeneous catalysis and the reaction mechanism study of supported metal catalysts.
支撑金属催化剂是异相催化领域应用最广泛的催化剂，其选择性控制对于在多径反应中获得所需的化学产物具有重要的科学意义，但一直是一个极具挑战性的问题。在这项工作中，我们证明了通过改变 M/Ce1-xPrxO2-δ（M = Ru、Rh）上 H 物种的还原活性，可以用一种稳健而独特的支撑掺杂策略来调节 CO2 加氢从 CH4 到 CO 的选择性。催化剂的 CH4 选择性随着载体中 Pr 含量的增加而降低。在 Ru/CeO2 上，CH4 的选择性高于 90%，而在 Ru/Ce0.2Pr0.8O2-δ 上，CO 的选择性达到 80%。该研究采用了稳态同位素瞬态动力学分析（SSITKA）、原位漫反射红外傅立叶变换光谱（DRIFTS）-质谱（MS）、温度编程解吸（TPD）和温度编程表面反应（TPSR）等多种技术，分析了掺杂 Pr 与 CO2 加氢反应选择性之间的结构-活性关系。在 CO2 加氢反应过程中，Ru 位点并不直接参与含碳中间产物（包括碳酸氢盐和甲酸盐）的加氢反应。支撑位点上的活性 H 物种与 RE3+-OH 结合，直接与含碳中间产物接触并发生反应。在载体中引入 Pr 削弱了载体的还原能力，从而降低了催化剂表面 H 物种的还原能力，进一步阻碍了甲酸酯向 CH4 的转化，导致 CH4 选择性下降。我们的研究清楚地揭示了载体在 CO2 加氢反应中的重要作用，并提出了通过载体掺杂调节反应选择性的策略。通过改变支持物的氧化还原性能，可以调节支持物上 H 物种的活性。从而影响重要反应中间产物（如甲酸盐）的转化，实现对反应产物的精确调节。我们为异相催化的选择性催化剂设计和支撑金属催化剂的反应机理研究提供了更广阔的视角。
{"title":"Tuning Selectivity of CO2 Hydrogenation via Support Composition Modification Adjusted the Activity Reduction of H Species over Ce1–xPrxO2−δ-Supported Metal (Ru, Rh) Nanoclusters","authors":"De-Jiu Wang, Xiao-Chen Sun, Hai-Jing Yin, Hao Dong, HaiChao Liu, Ya-Wen Zhang","doi":"10.1021/acscatal.4c01201","DOIUrl":"https://doi.org/10.1021/acscatal.4c01201","url":null,"abstract":"Selectivity control of supported metal catalysts, which are most widely utilized in the field of heterogeneous catalysis, is of great scientific significance to obtaining the desired chemical product in a multipath reaction but has remained a grand challenging issue. In this work, we demonstrate that the selectivity of CO<sub>2</sub> hydrogenation from CH<sub>4</sub> to CO can be tuned by a robust and unique support doping strategy by changing the reduction activity of H species over M/Ce<sub>1–<i>x</i></sub>Pr<sub><i>x</i></sub>O<sub>2−δ</sub> (M = Ru, Rh) in which metal (M) nanoclusters showed the same existence form on differently doped ceria nanorod supports. The CH<sub>4</sub> selectivity of the catalyst decreased with an increase in the Pr content in the support. The selectivity of CH<sub>4</sub> on Ru/CeO<sub>2</sub> was higher than 90%, while on Ru/Ce<sub>0.2</sub>Pr<sub>0.8</sub>O<sub>2−δ</sub>, the selectivity of CO reached 80%. A variety of techniques, including steady-state isotope transient kinetic analysis (SSITKA) type in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)–mass spectrum (MS), temperature-programmed desorption (TPD) and temperature-programmed surface reaction (TPSR), had been applied in this work to analyze the structure–activity relationship between the doping of Pr and the selectivity of the CO<sub>2</sub> hydrogenation reaction. Ru sites were not directly involved in the hydrogenation of carbon-containing intermediate species (including bicarbonate and formate) during the CO<sub>2</sub> hydrogenation reaction. The active H species on the support sites, which are incorporated in RE<sup>3+</sup>–OH, directly contacted and reacted with the carbon-containing intermediate species. The introduction of Pr in the support weakened the reducing ability of the support, thus decreasing the reducing ability of H species on the surface of the catalyst, which further hindered the conversion of formate into CH<sub>4</sub>, resulting in the declined CH<sub>4</sub> selectivity. Our study clearly revealed the important role of support in the CO<sub>2</sub> hydrogenation reaction and proposed a strategy to modulate the reaction selectivity via support doping. By changing the redox performance of the support, the activity of H species on the support can be adjusted. Thus, the conversion of important reaction intermediates (such as formate) can be affected, so as to achieve precise regulation of the reaction products. We have provided a broader perspective for the selective catalyst design of heterogeneous catalysis and the reaction mechanism study of supported metal catalysts.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-20DOI: 10.1021/acscatal.4c02656
Christopher W. Davis, Yanrong Li, Yu Zhang, Zohaib Siddiqi, Peng Liu, David Sarlah
We have achieved the arenophile-mediated, copper-catalyzed dearomative trans-1,2-carboamination of nonactivated arenes with alkyl organometallic nucleophiles. This simple and practical procedure was used to prepare diverse, stereochemically rich alkylated cyclohexadienes from readily available arenes. Synthetic utility was demonstrated through the rapid preparation of complex small molecules difficult to access by conventional routes. Finally, we conducted DFT studies to explore the catalytic process, including a study of the reaction pathway and an examination of the divergent regioselectivity observed with substituted arenes.
{"title":"Copper-Catalyzed Dearomative trans-1,2-Carboamination","authors":"Christopher W. Davis, Yanrong Li, Yu Zhang, Zohaib Siddiqi, Peng Liu, David Sarlah","doi":"10.1021/acscatal.4c02656","DOIUrl":"https://doi.org/10.1021/acscatal.4c02656","url":null,"abstract":"We have achieved the arenophile-mediated, copper-catalyzed dearomative <i>trans</i>-1,2-carboamination of nonactivated arenes with alkyl organometallic nucleophiles. This simple and practical procedure was used to prepare diverse, stereochemically rich alkylated cyclohexadienes from readily available arenes. Synthetic utility was demonstrated through the rapid preparation of complex small molecules difficult to access by conventional routes. Finally, we conducted DFT studies to explore the catalytic process, including a study of the reaction pathway and an examination of the divergent regioselectivity observed with substituted arenes.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141435909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-20DOI: 10.1021/acscatal.4c01793
Yiyang Zhou, Ruizhi Duan, Qing’e Huang, Chunmei Ding, Can Li
The artificial synthesis of amino acids is an important yet challenging subject. Electrocatalytic C–N coupling from organic acids and nitrogen sources provides an opportunity for this target but with the difficulty of C–N bond formation toward the production of amino acids. Herein, we report the synthesis of amino acids (alanine, glutamic acid, glycine, leucine, valine) from nitrate and α-ketoacids with a hybrid catalyst, cobalt phthalocyanine immobilized on carbon nanotubes (CoPc/CNT). The Faradaic efficiency for alanine production with CoPc/CNT is as high as 61%. The CoPc catalyst integrated with CNTs can catalyze nitrate reduction to hydroxylamine, which is switched from a thermodynamically uphill to a downhill process. The hydroxylamine intermediate attacks the α-carbon of an α-ketoacid to form an oxime. Amino acids are produced by the reduction of oximes catalyzed by CNTs. The bifunctionality of CoPc/CNT steers the tandem catalytic reaction toward the efficient production of amino acids in one pot. This work identifies that enhancing the reduction of nitrate to hydroxylamine is the key to C–N bond formation in amino acid synthesis.
{"title":"Amino Acid Synthesis through C–N Coupling between α-Ketoacids and Hydroxylamine from Nitrate Reduction","authors":"Yiyang Zhou, Ruizhi Duan, Qing’e Huang, Chunmei Ding, Can Li","doi":"10.1021/acscatal.4c01793","DOIUrl":"https://doi.org/10.1021/acscatal.4c01793","url":null,"abstract":"The artificial synthesis of amino acids is an important yet challenging subject. Electrocatalytic C–N coupling from organic acids and nitrogen sources provides an opportunity for this target but with the difficulty of C–N bond formation toward the production of amino acids. Herein, we report the synthesis of amino acids (alanine, glutamic acid, glycine, leucine, valine) from nitrate and α-ketoacids with a hybrid catalyst, cobalt phthalocyanine immobilized on carbon nanotubes (CoPc/CNT). The Faradaic efficiency for alanine production with CoPc/CNT is as high as 61%. The CoPc catalyst integrated with CNTs can catalyze nitrate reduction to hydroxylamine, which is switched from a thermodynamically uphill to a downhill process. The hydroxylamine intermediate attacks the α-carbon of an α-ketoacid to form an oxime. Amino acids are produced by the reduction of oximes catalyzed by CNTs. The bifunctionality of CoPc/CNT steers the tandem catalytic reaction toward the efficient production of amino acids in one pot. This work identifies that enhancing the reduction of nitrate to hydroxylamine is the key to C–N bond formation in amino acid synthesis.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-20DOI: 10.1021/acscatal.4c00812
Henrique F. Carvalho, Luuk Mestrom, Ulf Hanefeld, Jürgen Pleiss
Acyltransferase from Mycobacterium smegmatis is a versatile enzyme, which catalyzes the transesterification of esters in aqueous media due to a kinetic preference of the synthesis reaction over the thermodynamically favored hydrolysis reaction. In the active octamer, the active site is deeply buried and connected to the protein surface by long and hydrophobic substrate access channels. The role of the access channel in controlling catalytic activity and substrate specificity was investigated by molecular dynamics simulations and Markov-state models, and the thermodynamics and kinetics of binding of acyl donors, acceptors, and water were compared. Despite the hydrophobic nature of the substrate access channel, water is present in the channel and competes with the acyl acceptors for access to the active site. The binding free energy profiles in the access channel and the flux of butyl and benzyl alcohol and vinyl acetate were analyzed in the concentration range between 10 and 500 mM and compared to water. The flux showed a maximum at an alcohol concentration of 50–100 mM, in agreement with experimental observations. At the maximum, the flux of alcohol approaches 50% of the flux of water, which explains the high transesterification rate as compared to hydrolysis. The molecular origin of this effect is due to the accumulation of alcohol molecules along the access channel. Extensive molecular dynamics simulations and analysis of trajectories by a Markov-state model provided insights into the role of the access channel in activity and specificity by controlling access and binding of competing substrates.
烟曲霉分枝杆菌中的酰基转移酶是一种多功能酶，它在水介质中催化酯类的酯化反应，这是因为在动力学上合成反应比热力学上的水解反应更优先。在活性八聚体中，活性位点被深埋，并通过长而疏水的底物通道与蛋白质表面相连。分子动力学模拟和马尔可夫状态模型研究了通道在控制催化活性和底物特异性方面的作用，并比较了酰基供体、受体和水结合的热力学和动力学。尽管底物通道具有疏水性，但通道中仍存在水，并与酰基受体竞争进入活性位点。在 10 至 500 mM 的浓度范围内，分析了进入通道的结合自由能曲线以及丁醇、苯甲醇和乙酸乙烯酯的通量，并与水进行了比较。通量在酒精浓度为 50-100 mM 时达到最大值，这与实验观察结果一致。在最大值时，酒精的通量接近水通量的 50%，这就解释了为什么酯交换率比水解率高。造成这种效应的分子原因是酒精分子沿着通路聚集。利用马尔可夫状态模型进行的大量分子动力学模拟和轨迹分析，使人们深入了解了通道通过控制竞争底物的进入和结合在活性和特异性方面的作用。
{"title":"Beyond the Chemical Step: The Role of Substrate Access in Acyltransferase from Mycobacterium smegmatis","authors":"Henrique F. Carvalho, Luuk Mestrom, Ulf Hanefeld, Jürgen Pleiss","doi":"10.1021/acscatal.4c00812","DOIUrl":"https://doi.org/10.1021/acscatal.4c00812","url":null,"abstract":"Acyltransferase from <i>Mycobacterium smegmatis</i> is a versatile enzyme, which catalyzes the transesterification of esters in aqueous media due to a kinetic preference of the synthesis reaction over the thermodynamically favored hydrolysis reaction. In the active octamer, the active site is deeply buried and connected to the protein surface by long and hydrophobic substrate access channels. The role of the access channel in controlling catalytic activity and substrate specificity was investigated by molecular dynamics simulations and Markov-state models, and the thermodynamics and kinetics of binding of acyl donors, acceptors, and water were compared. Despite the hydrophobic nature of the substrate access channel, water is present in the channel and competes with the acyl acceptors for access to the active site. The binding free energy profiles in the access channel and the flux of butyl and benzyl alcohol and vinyl acetate were analyzed in the concentration range between 10 and 500 mM and compared to water. The flux showed a maximum at an alcohol concentration of 50–100 mM, in agreement with experimental observations. At the maximum, the flux of alcohol approaches 50% of the flux of water, which explains the high transesterification rate as compared to hydrolysis. The molecular origin of this effect is due to the accumulation of alcohol molecules along the access channel. Extensive molecular dynamics simulations and analysis of trajectories by a Markov-state model provided insights into the role of the access channel in activity and specificity by controlling access and binding of competing substrates.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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