Pub Date : 2024-12-20DOI: 10.1021/acscatal.4c06672
Jun-Bin Tang, Jun-Qian Bian, Zhihan Zhang, Yong-Feng Cheng, Li Qin, Qiang-Shuai Gu, Peiyuan Yu, Zhong-Liang Li, Xin-Yuan Liu
Organohalides are crucial in modern organic synthesis, thanks to their robust and versatile reactivity in cross-coupling and other key transformations. However, catalytic asymmetric methods for producing enantioenriched organohalides, particularly axially chiral vinyl halides, remain underdeveloped. Here, we present a Cu(I)-catalyzed, highly enantioselective radical alkyne 1,2-halofunctionalization, utilizing custom-designed tridentate anionic N,N,N-ligands with bulky peripheral substituents. This method efficiently employs (hetero)aryl and alkyl sulfonyl chlorides, as well as α-carbonyl alkyl bromides, as radical precursors and utilizes a diverse range of 2-amino and 2-oxy aryl terminal alkynes as substrates to produce highly enantioenriched axially chiral vinyl halides. The reaction is scalable to gram quantities, and the vinyl halides can be further transformed into axially chiral thiourea, pyridyl carboxamide, and quinolyl sulfonamide compounds, some of which show significant potential in asymmetric catalysis. Both experimental and theoretical mechanistic studies support an enantioselective halogen atom transfer mechanism. This method opens an avenue for accessing axially chiral organohalides, facilitating their broad applications in various related fields.
{"title":"Synthesis of Axially Chiral Vinyl Halides via Cu(I)-Catalyzed Enantioselective Radical 1,2-Halofunctionalization of Terminal Alkynes","authors":"Jun-Bin Tang, Jun-Qian Bian, Zhihan Zhang, Yong-Feng Cheng, Li Qin, Qiang-Shuai Gu, Peiyuan Yu, Zhong-Liang Li, Xin-Yuan Liu","doi":"10.1021/acscatal.4c06672","DOIUrl":"https://doi.org/10.1021/acscatal.4c06672","url":null,"abstract":"Organohalides are crucial in modern organic synthesis, thanks to their robust and versatile reactivity in cross-coupling and other key transformations. However, catalytic asymmetric methods for producing enantioenriched organohalides, particularly axially chiral vinyl halides, remain underdeveloped. Here, we present a Cu(I)-catalyzed, highly enantioselective radical alkyne 1,2-halofunctionalization, utilizing custom-designed tridentate anionic <i>N,N,N</i>-ligands with bulky peripheral substituents. This method efficiently employs (hetero)aryl and alkyl sulfonyl chlorides, as well as α-carbonyl alkyl bromides, as radical precursors and utilizes a diverse range of 2-amino and 2-oxy aryl terminal alkynes as substrates to produce highly enantioenriched axially chiral vinyl halides. The reaction is scalable to gram quantities, and the vinyl halides can be further transformed into axially chiral thiourea, pyridyl carboxamide, and quinolyl sulfonamide compounds, some of which show significant potential in asymmetric catalysis. Both experimental and theoretical mechanistic studies support an enantioselective halogen atom transfer mechanism. This method opens an avenue for accessing axially chiral organohalides, facilitating their broad applications in various related fields.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"13 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858190","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 : 2024-12-19DOI: 10.1021/acscatal.4c05816
Chen Peng, Haifeng Shen, Min Zheng, Mietek Jaroniec, Yao Zheng, Shi-Zhang Qiao
The electrochemical CO2 reduction reaction (CO2RR) is of great importance to produce valuable chemicals. In conventional alkaline and “acid + salts”-based CO2RR, the aqueous electrolyte normally needs to be refreshed due to the gradually more neutral feature of pH during electrolysis operation. Therefore, both solutes and deionized (DI) water in electrolytes are required to be regenerated regularly. In this work, acidic seawater (pH < 2) was used as a low-cost but efficient electrolyte for CO2RR without salt addition. The Faradaic efficiencies (FEs) and partial current densities of C2+ on typical copper in the “H2SO4 in raw seawater” electrolyte are comparable with those for conventional “KOH in DI water” and much higher than those for “H2SO4 + salts” systems. Moreover, single-pass carbon efficiencies (SPCEs) in acidic seawater are significantly higher than the values in alkaline DI water. Such an abnormal phenomenon was also demonstrated for CO and HCOOH generation on typical silver and tin catalysts, respectively. In situ Raman spectroscopy and controlled experiments revealed that metal (denoted as M) cations in seawater ensure a higher concentration of M·H2O species, which improve interactions with *CO2–, while Cl– anions enhance the adsorption strength of key CO2RR intermediates (namely, *CO on copper, *COO– on silver, and *OCHO on tin). Through these interactions with water molecules and CO2RR intermediates, such free but functional ions in seawater play a highly important role in promoting selectivity and activity for CO2RR, as well as SPCE in acidic seawater. Furthermore, using acidic seawater as an alternative CO2RR electrolyte has significant economic and ecological benefits compared with traditional alkaline DI water electrolytes.
{"title":"New Insights into CO2 Electroreduction in Acidic Seawater","authors":"Chen Peng, Haifeng Shen, Min Zheng, Mietek Jaroniec, Yao Zheng, Shi-Zhang Qiao","doi":"10.1021/acscatal.4c05816","DOIUrl":"https://doi.org/10.1021/acscatal.4c05816","url":null,"abstract":"The electrochemical CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) is of great importance to produce valuable chemicals. In conventional alkaline and “acid + salts”-based CO<sub>2</sub>RR, the aqueous electrolyte normally needs to be refreshed due to the gradually more neutral feature of pH during electrolysis operation. Therefore, both solutes and deionized (DI) water in electrolytes are required to be regenerated regularly. In this work, acidic seawater (pH < 2) was used as a low-cost but efficient electrolyte for CO<sub>2</sub>RR without salt addition. The Faradaic efficiencies (FEs) and partial current densities of C<sub>2+</sub> on typical copper in the “H<sub>2</sub>SO<sub>4</sub> in raw seawater” electrolyte are comparable with those for conventional “KOH in DI water” and much higher than those for “H<sub>2</sub>SO<sub>4</sub> + salts” systems. Moreover, single-pass carbon efficiencies (SPCEs) in acidic seawater are significantly higher than the values in alkaline DI water. Such an abnormal phenomenon was also demonstrated for CO and HCOOH generation on typical silver and tin catalysts, respectively. In situ Raman spectroscopy and controlled experiments revealed that metal (denoted as M) cations in seawater ensure a higher concentration of M·H<sub>2</sub>O species, which improve interactions with *CO<sub>2</sub><sup>–</sup>, while Cl<sup>–</sup> anions enhance the adsorption strength of key CO<sub>2</sub>RR intermediates (namely, *CO on copper, *COO<sup>–</sup> on silver, and *OCHO on tin). Through these interactions with water molecules and CO<sub>2</sub>RR intermediates, such free but functional ions in seawater play a highly important role in promoting selectivity and activity for CO<sub>2</sub>RR, as well as SPCE in acidic seawater. Furthermore, using acidic seawater as an alternative CO<sub>2</sub>RR electrolyte has significant economic and ecological benefits compared with traditional alkaline DI water electrolytes.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"53 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849836","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 : 2024-12-19DOI: 10.1021/acscatal.4c05551
Shingo Hasegawa, Shunta Tokutake, Koji Harano, Ken Motokura
Oxidative homocoupling of arenes is a challenging but attractive method for converting nonactivated aromatics into biaryl compounds. Applications and the mechanistic understanding of bimetallic nanocatalysts for arene C–H bond activation are limited at present. In this study, we found that a Pd–Ru bimetallic catalyst supported on Al2O3 showed remarkably high catalytic activity for the oxidative homocoupling of arenes owing to the synergistic effect between Pd and Ru. Structural analyses by high-angle annular dark-field scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy and X-ray absorption spectroscopy revealed that the Pd nanoparticles were decorated by partially oxidized Ru clusters. Mechanistic studies indicated that the arene C–H bond cleavage was the rate-determining step and proceeded by a concerted metalation–deprotonation mechanism. It was proposed that the role of Ru is promoting the C–H activation step by generating electron-deficient Pd sites, which was supported by DFT calculations. The Ru-decorated Pd nanoparticles showed large turnover numbers for simple arenes.
{"title":"Pd Nanoparticles Decorated by Oxidized Ru Clusters for Efficient C–H/C–H Coupling of Arenes","authors":"Shingo Hasegawa, Shunta Tokutake, Koji Harano, Ken Motokura","doi":"10.1021/acscatal.4c05551","DOIUrl":"https://doi.org/10.1021/acscatal.4c05551","url":null,"abstract":"Oxidative homocoupling of arenes is a challenging but attractive method for converting nonactivated aromatics into biaryl compounds. Applications and the mechanistic understanding of bimetallic nanocatalysts for arene C–H bond activation are limited at present. In this study, we found that a Pd–Ru bimetallic catalyst supported on Al<sub>2</sub>O<sub>3</sub> showed remarkably high catalytic activity for the oxidative homocoupling of arenes owing to the synergistic effect between Pd and Ru. Structural analyses by high-angle annular dark-field scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy and X-ray absorption spectroscopy revealed that the Pd nanoparticles were decorated by partially oxidized Ru clusters. Mechanistic studies indicated that the arene C–H bond cleavage was the rate-determining step and proceeded by a concerted metalation–deprotonation mechanism. It was proposed that the role of Ru is promoting the C–H activation step by generating electron-deficient Pd sites, which was supported by DFT calculations. The Ru-decorated Pd nanoparticles showed large turnover numbers for simple arenes.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"55 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858063","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}
The orbital hybridization between metal and oxygen of perovskite catalysts can lower the overpotential and enhance the oxygen evolution reaction (OER) activity. This study combines density functional theory with experiments to clarify how Sr/Fe codoping modulates orbital hybridization and enhances OER catalytic activity of LaCoO3. The as-prepared La0.50Sr0.50Co0.75Fe0.25O3 shows remarkable performance with a low overpotential of 310 mV at 10 mA cm–2 current density and a 107.03 mV dec–1 Tafel slope, outperforming most state-of-the-art perovskite-based OER electrocatalysts. The experimental results confirm that Sr/Fe codoping enhances the expansion of Co–O–Co bond angles and strengthens the covalency of the Co–O bond in LaCoO3, leading to enhanced electrocatalytic activity. Moreover, increasing Sr doping reduces the distance between the Co 3d/O 2p center and the Fermi level, decreasing the energy difference between them and enhancing the degree of orbital hybridization between Co 3d and O 2p. As the degree of Co 3d/O 2p orbital hybridization increases, a higher charge transfer was found between the active center and intermediate product, OOH, reducing the energy barrier of the rate-determining step while lowering the overpotential. This study provides thorough insight into the rational design of OER catalysts based on orbital hybridization.
过氧化物催化剂中金属和氧之间的轨道杂化可以降低过电位，提高氧进化反应（OER）活性。本研究将密度泛函理论与实验相结合，阐明了 Sr/Fe 共掺如何调节 LaCoO3 的轨道杂化并提高其 OER 催化活性。制备的 La0.50Sr0.50Co0.75Fe0.25O3 表现出卓越的性能，在 10 mA cm-2 电流密度下过电位低至 310 mV，塔菲尔斜率为 107.03 mV dec-1，优于大多数最先进的基于包晶石的 OER 电催化剂。实验结果证实，Sr/Fe 共掺可增强 LaCoO3 中 Co-O-Co 键角度的扩展，加强 Co-O 键的共价性，从而提高电催化活性。此外，增加 Sr 掺杂会减小 Co 3d/O 2p 中心与费米级之间的距离，从而减小它们之间的能差、提高 Co 3d 与 O 2p 之间的轨道杂化程度。随着 Co 3d/O 2p 轨道杂化程度的增加，活性中心与中间产物 OOH 之间的电荷转移也随之增加，从而降低了决定速率步骤的能垒，同时降低了过电位。这项研究为基于轨道杂化的 OER 催化剂的合理设计提供了深入的见解。
{"title":"Controlling Co 3d/O 2p Orbital Hybridization in LaCoO3 by Modulating the Co–O–Co Bond Angle for Enhanced Oxygen Evolution Reaction Catalysis","authors":"Baoxin Ge, Pengyang Jiang, Biyi Chen, Caijin Huang","doi":"10.1021/acscatal.4c05479","DOIUrl":"https://doi.org/10.1021/acscatal.4c05479","url":null,"abstract":"The orbital hybridization between metal and oxygen of perovskite catalysts can lower the overpotential and enhance the oxygen evolution reaction (OER) activity. This study combines density functional theory with experiments to clarify how Sr/Fe codoping modulates orbital hybridization and enhances OER catalytic activity of LaCoO<sub>3</sub>. The as-prepared La<sub>0.50</sub>Sr<sub>0.50</sub>Co<sub>0.75</sub>Fe<sub>0.25</sub>O<sub>3</sub> shows remarkable performance with a low overpotential of 310 mV at 10 mA cm<sup>–2</sup> current density and a 107.03 mV dec<sup>–1</sup> Tafel slope, outperforming most state-of-the-art perovskite-based OER electrocatalysts. The experimental results confirm that Sr/Fe codoping enhances the expansion of Co–O–Co bond angles and strengthens the covalency of the Co–O bond in LaCoO<sub>3</sub>, leading to enhanced electrocatalytic activity. Moreover, increasing Sr doping reduces the distance between the Co 3d/O 2p center and the Fermi level, decreasing the energy difference between them and enhancing the degree of orbital hybridization between Co 3d and O 2p. As the degree of Co 3d/O 2p orbital hybridization increases, a higher charge transfer was found between the active center and intermediate product, OOH, reducing the energy barrier of the rate-determining step while lowering the overpotential. This study provides thorough insight into the rational design of OER catalysts based on orbital hybridization.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"11 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858192","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 : 2024-12-19DOI: 10.1021/acscatal.4c04938
He Li, Fener Chen, Wei Ding, Qi Zhang
Arsinothricin (AST) is a broad-spectrum arsenic-containing antibiotic with promising pharmaceutical properties. In this study, we report the one-pot chemoenzymatic synthesis of AST starting from methylarsenate, a commonly used agricultural herbicide. Although a single point mutation in the C-terminal region of ArsL completely abolished its activity toward the natural substrate inorganic arsenite, this mutation unexpectedly enhanced its activity toward methylarsenate by over 50-fold, enabling subgram scale production of AST in a cell-free system. These findings offer valuable mechanistic insights into ArsL and highlight the significant potential of manipulating the radical SAM superfamily enzymes in synthetic applications.
Arsinothricin (AST) 是一种广谱含砷抗生素，具有广阔的药用前景。在本研究中，我们报告了以常用的农用除草剂甲胂酸为原料，一步化学合成 AST 的过程。虽然 ArsL C 端区域的单点突变完全取消了其对天然底物无机亚砷酸盐的活性，但这一突变却意外地将其对甲砷酸盐的活性提高了 50 倍以上，从而实现了在无细胞系统中亚克规模生产 AST。这些发现为 ArsL 提供了宝贵的机理启示，并凸显了在合成应用中操纵自由基 SAM 超家族酶的巨大潜力。
{"title":"One-Pot Chemoenzymatic Synthesis of Arsinothricin and the Mechanistic Insights into the Noncanonical Radical SAM Enzyme ArsL","authors":"He Li, Fener Chen, Wei Ding, Qi Zhang","doi":"10.1021/acscatal.4c04938","DOIUrl":"https://doi.org/10.1021/acscatal.4c04938","url":null,"abstract":"Arsinothricin (AST) is a broad-spectrum arsenic-containing antibiotic with promising pharmaceutical properties. In this study, we report the one-pot chemoenzymatic synthesis of AST starting from methylarsenate, a commonly used agricultural herbicide. Although a single point mutation in the C-terminal region of ArsL completely abolished its activity toward the natural substrate inorganic arsenite, this mutation unexpectedly enhanced its activity toward methylarsenate by over 50-fold, enabling subgram scale production of AST in a cell-free system. These findings offer valuable mechanistic insights into ArsL and highlight the significant potential of manipulating the radical SAM superfamily enzymes in synthetic applications.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"261 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858060","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 : 2024-12-18DOI: 10.1021/acscatal.4c06557
Hanliang Zheng, Liu Cai, Xiaoyu Lai, Muhammet Uyanik, Kazuaki Ishihara, Xiao-Song Xue
Despite the widespread use of hexafluoropropanol (HFIP) as a “magic” solvent or additive in organic synthesis, its fundamental mechanisms lag far behind. This study presents mechanistic insights into the puzzling alcohol additive effects observed in Ishihara’s conformationally flexible C2-symmetric iodoarene-catalyzed asymmetric phenolic dearomatization through density functional theory calculations. The results reveal that due to the “booster effect” of fluorinated alcohols, HFIP assembles a trimeric hydrogen bond cluster that displaces a ligand from the active iodine(III) catalyst and forms a low-barrier hydrogen bond with the substrate, which significantly enhances the oxidizing power of the iodine(III) center, thus facilitating the dearomatization of electron-deficient phenols. Conversely, methanol is found to promote the dearomatization of electron-rich phenols via a formally similar yet distinct mechanism, thus highlighting the unique role of HFIP as an additive. The insights gained from this investigation advance our molecular-level understanding of the synergistic interactions between catalysts and additives, potentially guiding the design of catalytic systems that exploit these effects for broader applications.
{"title":"Unraveling Alcohol Additive Effects on Hypervalent Iodine(III)-Catalyzed Asymmetric Phenolic Dearomatization: Ligand Substitution and Low-Barrier Hydrogen Bonds","authors":"Hanliang Zheng, Liu Cai, Xiaoyu Lai, Muhammet Uyanik, Kazuaki Ishihara, Xiao-Song Xue","doi":"10.1021/acscatal.4c06557","DOIUrl":"https://doi.org/10.1021/acscatal.4c06557","url":null,"abstract":"Despite the widespread use of hexafluoropropanol (HFIP) as a “magic” solvent or additive in organic synthesis, its fundamental mechanisms lag far behind. This study presents mechanistic insights into the puzzling alcohol additive effects observed in Ishihara’s conformationally flexible C2-symmetric iodoarene-catalyzed asymmetric phenolic dearomatization through density functional theory calculations. The results reveal that due to the “booster effect” of fluorinated alcohols, HFIP assembles a trimeric hydrogen bond cluster that displaces a ligand from the active iodine(III) catalyst and forms a low-barrier hydrogen bond with the substrate, which significantly enhances the oxidizing power of the iodine(III) center, thus facilitating the dearomatization of electron-deficient phenols. Conversely, methanol is found to promote the dearomatization of electron-rich phenols via a formally similar yet distinct mechanism, thus highlighting the unique role of HFIP as an additive. The insights gained from this investigation advance our molecular-level understanding of the synergistic interactions between catalysts and additives, potentially guiding the design of catalytic systems that exploit these effects for broader applications.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"258 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142840944","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 : 2024-12-18DOI: 10.1021/acscatal.4c05532
Jesse E. Matthews, Jaime E. Avilés Acosta, Sang-Won Lee, Dongrak Oh, Tiras Y. Lin, Kyra M. K. Yap, Junjie Chen, Ji-Wook Jang, Dong Un Lee, Adam C. Nielander, Thomas F. Jaramillo
The reaction microenvironment plays a key role in dictating the selectivity of electrochemical CO2 reduction. However, understanding the chemical nature of this microenvironment under operating conditions remains a substantial challenge. We employed attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) in operando for simultaneous measurements of reaction kinetics and concentrations of reactants and intermediates at the reaction interface, all under controlled mass transport conditions. These operando measurements enable direct correlations between the reaction microenvironment, mass transport, and kinetics for a Cu electrocatalyst, such as higher local concentrations of CO2 under faster mass transport corresponding to higher rates of CO2 reduction. We observed that faster mass transport decreased the *CO coverage at less negative potentials (−0.6 VRHE) and increased the *CO coverage at more negative potentials (−1.1 VRHE). We developed a transport-coupled kinetic model that captures these spectroscopic observations and provides insight into the processes controlling interfacial concentrations of reactants and intermediates, aiding future efforts toward tailoring reaction microenvironments.
{"title":"Operando Surface-Enhanced Infrared Spectroscopy Connects Interfacial Dynamics with Reaction Kinetics During Electrochemical CO2 Reduction on Copper","authors":"Jesse E. Matthews, Jaime E. Avilés Acosta, Sang-Won Lee, Dongrak Oh, Tiras Y. Lin, Kyra M. K. Yap, Junjie Chen, Ji-Wook Jang, Dong Un Lee, Adam C. Nielander, Thomas F. Jaramillo","doi":"10.1021/acscatal.4c05532","DOIUrl":"https://doi.org/10.1021/acscatal.4c05532","url":null,"abstract":"The reaction microenvironment plays a key role in dictating the selectivity of electrochemical CO<sub>2</sub> reduction. However, understanding the chemical nature of this microenvironment under operating conditions remains a substantial challenge. We employed attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) <i>in operando</i> for simultaneous measurements of reaction kinetics and concentrations of reactants and intermediates at the reaction interface, all under controlled mass transport conditions. These <i>operando</i> measurements enable direct correlations between the reaction microenvironment, mass transport, and kinetics for a Cu electrocatalyst, such as higher local concentrations of CO<sub>2</sub> under faster mass transport corresponding to higher rates of CO<sub>2</sub> reduction. We observed that faster mass transport decreased the *CO coverage at less negative potentials (−0.6 V<sub>RHE</sub>) and increased the *CO coverage at more negative potentials (−1.1 V<sub>RHE</sub>). We developed a transport-coupled kinetic model that captures these spectroscopic observations and provides insight into the processes controlling interfacial concentrations of reactants and intermediates, aiding future efforts toward tailoring reaction microenvironments.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"1 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142840942","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}
Electrochemical C–N coupling between CO2 and N-containing small molecules is a promising strategy to close both the carbon and nitrogen loops to support the establishment of a net-zero carbon economy. However, the intricate reaction network and the contentious C–N coupling mechanism hinder the development of efficient electrocatalysts for industrial applications. Herein, we develop a graph-based approach to enable autonomous analysis of the C–N coupling mechanism for coreduction of CO2 and NO3– on single-atom catalysts (SACs). 1400 potential intermediates and 2490 C–N coupling modes are investigated based on the Cu-N4-C prototypical catalyst. We demonstrate that N-containing species with a higher reduction degree are more likely to undergo C–N coupling and the initial coupling of the C–N bond tends to occur on CO2. It is revealed that the hydrogenation energies of *NH2 and CO2, as well as their coupling energies, can serve as key indicators for catalyst recommendation. Using this approach, SACs with Mo, W, or Sb metal centers are identified as promising electrocatalysts for C–N coupling. This work presents a paradigm for automatically exploring the mechanisms of complex electrocatalytic reactions and offers a strategy for predicting highly active and selective SACs.
{"title":"Autonomous Exploitation of Reaction Pathways for Electrochemical C–N Coupling on Single-Atom Catalysts","authors":"Junjie Pan, Haowen Ding, Xinzhe Yang, Xianhui Liang, Shanglin Wu, Mingzheng Zhang, Shunning Li, Shisheng Zheng, Feng Pan","doi":"10.1021/acscatal.4c05751","DOIUrl":"https://doi.org/10.1021/acscatal.4c05751","url":null,"abstract":"Electrochemical C–N coupling between CO<sub>2</sub> and N-containing small molecules is a promising strategy to close both the carbon and nitrogen loops to support the establishment of a net-zero carbon economy. However, the intricate reaction network and the contentious C–N coupling mechanism hinder the development of efficient electrocatalysts for industrial applications. Herein, we develop a graph-based approach to enable autonomous analysis of the C–N coupling mechanism for coreduction of CO<sub>2</sub> and NO<sub>3</sub><sup>–</sup> on single-atom catalysts (SACs). 1400 potential intermediates and 2490 C–N coupling modes are investigated based on the Cu-N<sub>4</sub>-C prototypical catalyst. We demonstrate that N-containing species with a higher reduction degree are more likely to undergo C–N coupling and the initial coupling of the C–N bond tends to occur on CO<sub>2</sub>. It is revealed that the hydrogenation energies of *NH<sub>2</sub> and CO<sub>2</sub>, as well as their coupling energies, can serve as key indicators for catalyst recommendation. Using this approach, SACs with Mo, W, or Sb metal centers are identified as promising electrocatalysts for C–N coupling. This work presents a paradigm for automatically exploring the mechanisms of complex electrocatalytic reactions and offers a strategy for predicting highly active and selective SACs.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"96 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849834","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 : 2024-12-18DOI: 10.1021/acscatal.4c04472
Elena Di Simone, Gianvito Vilé, Giovanni Di Liberto, Gianfranco Pacchioni
Single-atom catalysts (SACs) are rapidly gaining attention as a versatile class of materials that combine the advantages of both homogeneous and heterogeneous catalysis. A growing number of studies aim to identify potential new SACs or to describe their structure and reactivity through ab initio quantum chemical simulations. While many computational studies primarily address reactions involving small molecules, such as water splitting or CO2 reduction, the application scope of SACs is rapidly broadening to include the production of fine chemicals and the conversion of biomass-derived platform molecules, processes that involve larger, more complex reactants. Using density-functional theory (DFT) simulations, we demonstrate that, while an approximate treatment of entropy is acceptable for molecules with up to three atoms, it introduces substantial errors in reactions involving more complex molecules. Our results reveal a linear correlation between the entropy of adsorbed molecules and that of the corresponding isolated species, mirroring trends observed on extended catalytic surfaces. For the largest systems investigated in this study, the entropy of the free molecule is reduced by approximately 10–20% upon adsorption; for small molecules, this reduction can range from 50 to 70%. This disparity arises because, on SACs, the translational entropy is effectively zero, the rotational entropy is minimal, and the vibrational entropy increases with the size of the molecule. Moreover, the entropy of adsorbates scales linearly with the number of atoms in the molecule, allowing for the prediction of entropic contributions of adsorbates on SACs without additional computational cost. Using propyne hydrogenation as a test, we demonstrate that the reaction energy profile computed with current approximate approaches for estimating the entropy of adsorbates differs significantly from the profile where entropy is explicitly included. These findings highlight the importance of considering adsorbate entropy for accurately predicting the catalytic activity of SACs, particularly for reactions involving complex molecules.
{"title":"Decoding the Role of Adsorbates Entropy in the Reactivity of Single-Atom Catalysts","authors":"Elena Di Simone, Gianvito Vilé, Giovanni Di Liberto, Gianfranco Pacchioni","doi":"10.1021/acscatal.4c04472","DOIUrl":"https://doi.org/10.1021/acscatal.4c04472","url":null,"abstract":"Single-atom catalysts (SACs) are rapidly gaining attention as a versatile class of materials that combine the advantages of both homogeneous and heterogeneous catalysis. A growing number of studies aim to identify potential new SACs or to describe their structure and reactivity through ab initio quantum chemical simulations. While many computational studies primarily address reactions involving small molecules, such as water splitting or CO<sub>2</sub> reduction, the application scope of SACs is rapidly broadening to include the production of fine chemicals and the conversion of biomass-derived platform molecules, processes that involve larger, more complex reactants. Using density-functional theory (DFT) simulations, we demonstrate that, while an approximate treatment of entropy is acceptable for molecules with up to three atoms, it introduces substantial errors in reactions involving more complex molecules. Our results reveal a linear correlation between the entropy of adsorbed molecules and that of the corresponding isolated species, mirroring trends observed on extended catalytic surfaces. For the largest systems investigated in this study, the entropy of the free molecule is reduced by approximately 10–20% upon adsorption; for small molecules, this reduction can range from 50 to 70%. This disparity arises because, on SACs, the translational entropy is effectively zero, the rotational entropy is minimal, and the vibrational entropy increases with the size of the molecule. Moreover, the entropy of adsorbates scales linearly with the number of atoms in the molecule, allowing for the prediction of entropic contributions of adsorbates on SACs without additional computational cost. Using propyne hydrogenation as a test, we demonstrate that the reaction energy profile computed with current approximate approaches for estimating the entropy of adsorbates differs significantly from the profile where entropy is explicitly included. These findings highlight the importance of considering adsorbate entropy for accurately predicting the catalytic activity of SACs, particularly for reactions involving complex molecules.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"60 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849839","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 : 2024-12-18DOI: 10.1021/acscatal.4c05458
Xiaoyu Li, Lichen Liu
Hydrothermal stability is a vital performance criterion considered in the design of heterogeneous metal catalysts for practical applications because of the widespread presence of moisture in the reaction feeds or the products. In this work, we substantially promote the hydrothermal stability of the Pt-zeolite catalyst by incorporating Sn into the zeolite framework. Pt species are stabilized as small nanoparticles, and the MFI zeolite structure is well preserved even after hydrothermal treatment at 850 °C in a mixed atmosphere (CO + O2 + H2O). Adding Sn into Pt-MFI not only heals the defect sites in pure-silica MFI zeolite to promote its structural stability during hydrothermal treatment but also stabilizes the mobile PtOx species via the Sn–O–Pt interaction. The remarkably high stability of the Pt particles encapsulated in the Sn-promoted MFI zeolite is reflected in the CO oxidation reaction in which Pt particles stabilized in the Sn-promoted MFI zeolite exhibit much higher stability than the nonpromoted Pt-MFI catalyst. The stabilization effect of Sn is further extended to a Pd-MFI zeolite catalyst in which the average size of the Pd particles remains below 2 nm after the harsh hydrothermal treatments at 850 °C.
{"title":"Hydrothermally Stable Zeolite-Encapsulated Metal Catalyst Promoted by Framework Sn Species","authors":"Xiaoyu Li, Lichen Liu","doi":"10.1021/acscatal.4c05458","DOIUrl":"https://doi.org/10.1021/acscatal.4c05458","url":null,"abstract":"Hydrothermal stability is a vital performance criterion considered in the design of heterogeneous metal catalysts for practical applications because of the widespread presence of moisture in the reaction feeds or the products. In this work, we substantially promote the hydrothermal stability of the Pt-zeolite catalyst by incorporating Sn into the zeolite framework. Pt species are stabilized as small nanoparticles, and the MFI zeolite structure is well preserved even after hydrothermal treatment at 850 °C in a mixed atmosphere (CO + O<sub>2</sub> + H<sub>2</sub>O). Adding Sn into Pt-MFI not only heals the defect sites in pure-silica MFI zeolite to promote its structural stability during hydrothermal treatment but also stabilizes the mobile PtO<sub><i>x</i></sub> species via the Sn–O–Pt interaction. The remarkably high stability of the Pt particles encapsulated in the Sn-promoted MFI zeolite is reflected in the CO oxidation reaction in which Pt particles stabilized in the Sn-promoted MFI zeolite exhibit much higher stability than the nonpromoted Pt-MFI catalyst. The stabilization effect of Sn is further extended to a Pd-MFI zeolite catalyst in which the average size of the Pd particles remains below 2 nm after the harsh hydrothermal treatments at 850 °C.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"49 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142840940","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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