Pub Date : 2024-06-26DOI: 10.1038/s41929-024-01161-0
Aaron J. Kaufman, Adam C. Nielander, Gerald J. Meyer, Stephen Maldonado, Shane Ardo, Shannon W. Boettcher
The absolute band-edge potentials of semiconductors and their positions relative to solution redox potentials are often invoked as design principles for photoelectrochemical devices and particulate photocatalysts. Here we show that these criteria are not necessary and limit the exploration of materials that may advance the fields of photoelectrochemistry, photochemistry and photocatalysis. We discuss how band-edge energies are not singular parameters and instead shift with pH, electrolyte type and surface chemistry. The free energies of electrons and holes, rather than those of solution redox couples, dictate overall reaction spontaneity and thus reactivity. Favourable charge-transfer kinetics can occur even when the relevant electrolyte redox potential(s) appear outside the bandgap, enabled by the inversion or accumulation of electronic charge at the semiconductor surface. This discussion informs design principles for photocatalytic systems engineering for both one-electron and multi-electron redox reactions (for example, H2 evolution, H2O oxidation and CO2 reduction). The absolute position of band edges is widely considered an indispensable design principle for selection of appropriate semiconductors for a given photo(electro)catalytic reaction. In this Perspective, the authors re-examine this idea from a viewpoint of semiconductor physics and make the case that alignment of band edges with chemical redox potentials is of limited importance.
半导体的绝对带边电位及其相对于溶液氧化还原电位的位置经常被用作光电化学装置和微粒光催化剂的设计原则。在这里，我们要说明的是，这些标准并非必要，它们限制了对可能推动光电化学、光化学和光催化领域发展的材料的探索。我们讨论了带边能量并非单一参数，而是会随着 pH 值、电解质类型和表面化学而变化。电子和空穴的自由能，而不是溶液氧化还原偶的自由能，决定了整个反应的自发性，从而决定了反应活性。即使相关的电解质氧化还原电位出现在带隙之外，通过半导体表面电子电荷的反转或积累，也会产生有利的电荷转移动力学。这一讨论为单电子和多电子氧化还原反应（如 H2 演化、H2O 氧化和 CO2 还原）的光催化系统工程设计原则提供了参考。
{"title":"Absolute band-edge energies are over-emphasized in the design of photoelectrochemical materials","authors":"Aaron J. Kaufman, Adam C. Nielander, Gerald J. Meyer, Stephen Maldonado, Shane Ardo, Shannon W. Boettcher","doi":"10.1038/s41929-024-01161-0","DOIUrl":"10.1038/s41929-024-01161-0","url":null,"abstract":"The absolute band-edge potentials of semiconductors and their positions relative to solution redox potentials are often invoked as design principles for photoelectrochemical devices and particulate photocatalysts. Here we show that these criteria are not necessary and limit the exploration of materials that may advance the fields of photoelectrochemistry, photochemistry and photocatalysis. We discuss how band-edge energies are not singular parameters and instead shift with pH, electrolyte type and surface chemistry. The free energies of electrons and holes, rather than those of solution redox couples, dictate overall reaction spontaneity and thus reactivity. Favourable charge-transfer kinetics can occur even when the relevant electrolyte redox potential(s) appear outside the bandgap, enabled by the inversion or accumulation of electronic charge at the semiconductor surface. This discussion informs design principles for photocatalytic systems engineering for both one-electron and multi-electron redox reactions (for example, H2 evolution, H2O oxidation and CO2 reduction). The absolute position of band edges is widely considered an indispensable design principle for selection of appropriate semiconductors for a given photo(electro)catalytic reaction. In this Perspective, the authors re-examine this idea from a viewpoint of semiconductor physics and make the case that alignment of band edges with chemical redox potentials is of limited importance.","PeriodicalId":18845,"journal":{"name":"Nature Catalysis","volume":null,"pages":null},"PeriodicalIF":42.8,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461891","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 : 2024-06-24DOI: 10.1038/s41929-024-01179-4
Zhi-Ming Zhang, Tao Wang, Yu-Chen Cai, Xiao-Yu Li, Jin-Yu Ye, Yao Zhou, Na Tian, Zhi-You Zhou, Shi-Gang Sun
Tuning the properties of the electric double layer via cations is a recognized approach for improving the efficiency of the CO2 reduction reaction (CO2RR). However, the mechanism behind cation-enhanced CO2RR kinetics remains puzzling. Here we identify the key intermediate, adsorbed CO2, via in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy on Cu in an acidic electrolyte, confirming it appears only in the presence of cations. Different from prevalent viewpoints, time-resolved infrared spectra reveal that Li+ enhances CO2 adsorption more effectively than other larger cations but slows down the hydrogenation kinetics of CO2. Ab initio molecular dynamics simulations and spectroscopic features of water suggest that rigid water networks around Li+ impedes the hydrogen of water to approach adsorbed CO2. In contrast, more flexible water networks around larger cations (for example, Na+) facilitate water reorientation and enhance hydrogen proximity to CO2, thereby improving CO2RR. This study highlights the essential role of interfacial water structure in CO2RR efficiency. CO2 electroreduction is promoted by alkali cations in the electrolyte, but the precise mechanism by which this occurs is not clear. Now in situ infrared spectroscopy and ab initio molecular dynamics are combined to elucidate the specific role of alkali cations and their trends.
通过阳离子调节电双层的特性是一种公认的提高二氧化碳还原反应（CO2RR）效率的方法。然而，阳离子增强 CO2RR 动力学背后的机制仍然令人费解。在这里，我们通过对酸性电解质中的铜进行原位衰减全反射表面增强红外吸收光谱分析，确定了关键的中间产物--吸附的 CO2，并证实它只在阳离子存在时出现。与普遍观点不同的是，时间分辨红外光谱显示 Li+ 比其他较大的阳离子更有效地增强了对二氧化碳的吸附，但却减慢了二氧化碳的氢化动力学。Ab initio 分子动力学模拟和水的光谱特征表明，Li+ 周围的刚性水网络阻碍了水的氢接近被吸附的 CO2。相比之下，大阳离子（如 Na+）周围更柔性的水网络则有利于水的重新定向，增强氢接近 CO2 的能力，从而提高 CO2RR。这项研究强调了界面水结构在 CO2RR 效率中的重要作用。
{"title":"Probing electrolyte effects on cation-enhanced CO2 reduction on copper in acidic media","authors":"Zhi-Ming Zhang, Tao Wang, Yu-Chen Cai, Xiao-Yu Li, Jin-Yu Ye, Yao Zhou, Na Tian, Zhi-You Zhou, Shi-Gang Sun","doi":"10.1038/s41929-024-01179-4","DOIUrl":"10.1038/s41929-024-01179-4","url":null,"abstract":"Tuning the properties of the electric double layer via cations is a recognized approach for improving the efficiency of the CO2 reduction reaction (CO2RR). However, the mechanism behind cation-enhanced CO2RR kinetics remains puzzling. Here we identify the key intermediate, adsorbed CO2, via in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy on Cu in an acidic electrolyte, confirming it appears only in the presence of cations. Different from prevalent viewpoints, time-resolved infrared spectra reveal that Li+ enhances CO2 adsorption more effectively than other larger cations but slows down the hydrogenation kinetics of CO2. Ab initio molecular dynamics simulations and spectroscopic features of water suggest that rigid water networks around Li+ impedes the hydrogen of water to approach adsorbed CO2. In contrast, more flexible water networks around larger cations (for example, Na+) facilitate water reorientation and enhance hydrogen proximity to CO2, thereby improving CO2RR. This study highlights the essential role of interfacial water structure in CO2RR efficiency. CO2 electroreduction is promoted by alkali cations in the electrolyte, but the precise mechanism by which this occurs is not clear. Now in situ infrared spectroscopy and ab initio molecular dynamics are combined to elucidate the specific role of alkali cations and their trends.","PeriodicalId":18845,"journal":{"name":"Nature Catalysis","volume":null,"pages":null},"PeriodicalIF":42.8,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444960","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 : 2024-06-14DOI: 10.1038/s41929-024-01169-6
Yuhang Dai, Ruihu Lu, Chengyi Zhang, Jiantao Li, Yifei Yuan, Yu Mao, Chumei Ye, Zhijun Cai, Jiexin Zhu, Jinghao Li, Ruohan Yu, Lianmeng Cui, Siyu Zhao, Qinyou An, Guanjie He, Geoffrey I. N. Waterhouse, Paul R. Shearing, Yang Ren, Jun Lu, Khalil Amine, Ziyun Wang, Liqiang Mai
Rechargeable aqueous zinc-ion batteries (AZIBs), renowned for their safety, high energy density and rapid charging, are prime choices for grid-scale energy storage. Historically, ion-shuttling models centring on ion-migration behaviour have dominated explanations for charge/discharge processes in aqueous batteries, like classical ion insertion/extraction and pseudocapacitance mechanisms. However, these models struggle to account for the exceptional performance of AZIBs compared to other aqueous metal-ion batteries. Here we present a catalysis model elucidating the Zn2+ anomaly in aqueous batteries, explaining it through the concept of adsorption in catalysis. Such behaviour can serve the charge/discharge role, predominantly dictated by solvated metal cations and cathode materials. First-principles calculations suggest optimal adsorption/desorption behaviour (water dissociation process) with the Zn2+–vanadium nitride (VN) combination. Experimentally, AZIBs implementing VN cathodes demonstrate fast-charging kinetics, showing a capacity of 577.1 mAh g−1 at a current density of 300,000 mA g−1. The grasp of catalysis steps within AZIBs can drive solutions beyond state-of-the-art fast-charging batteries. Aqueous Zn-ion batteries are promising devices but their energy storage mechanism remains elusive. Now it is shown that these involve a catalytic mechanism based on water dissociation.
可充电锌离子水电池（AZIBs）以其安全性、高能量密度和快速充电而著称，是电网规模能源存储的首选。从历史上看，以离子迁移行为为核心的离子跃迁模型一直主导着对水电池充放电过程的解释，如经典的离子插入/抽出和假电容机制。然而，与其他水性金属离子电池相比，这些模型难以解释 AZIB 的优异性能。在此，我们提出一种催化模型，通过催化中的吸附概念来解释水电池中的 Zn2+ 异常现象。这种行为可以起到充电/放电的作用，主要由溶解的金属阳离子和阴极材料决定。第一原理计算表明，Zn2+-氮化钒（VN）组合具有最佳的吸附/解吸行为（水解离过程）。在实验中，采用氮化钒阴极的 AZIBs 显示出快速充电动力学，在电流密度为 300,000 mA g-1 时，容量为 577.1 mAh g-1。掌握 AZIB 内的催化步骤可以推动解决方案超越最先进的快速充电电池。
{"title":"Zn2+-mediated catalysis for fast-charging aqueous Zn-ion batteries","authors":"Yuhang Dai, Ruihu Lu, Chengyi Zhang, Jiantao Li, Yifei Yuan, Yu Mao, Chumei Ye, Zhijun Cai, Jiexin Zhu, Jinghao Li, Ruohan Yu, Lianmeng Cui, Siyu Zhao, Qinyou An, Guanjie He, Geoffrey I. N. Waterhouse, Paul R. Shearing, Yang Ren, Jun Lu, Khalil Amine, Ziyun Wang, Liqiang Mai","doi":"10.1038/s41929-024-01169-6","DOIUrl":"10.1038/s41929-024-01169-6","url":null,"abstract":"Rechargeable aqueous zinc-ion batteries (AZIBs), renowned for their safety, high energy density and rapid charging, are prime choices for grid-scale energy storage. Historically, ion-shuttling models centring on ion-migration behaviour have dominated explanations for charge/discharge processes in aqueous batteries, like classical ion insertion/extraction and pseudocapacitance mechanisms. However, these models struggle to account for the exceptional performance of AZIBs compared to other aqueous metal-ion batteries. Here we present a catalysis model elucidating the Zn2+ anomaly in aqueous batteries, explaining it through the concept of adsorption in catalysis. Such behaviour can serve the charge/discharge role, predominantly dictated by solvated metal cations and cathode materials. First-principles calculations suggest optimal adsorption/desorption behaviour (water dissociation process) with the Zn2+–vanadium nitride (VN) combination. Experimentally, AZIBs implementing VN cathodes demonstrate fast-charging kinetics, showing a capacity of 577.1 mAh g−1 at a current density of 300,000 mA g−1. The grasp of catalysis steps within AZIBs can drive solutions beyond state-of-the-art fast-charging batteries. Aqueous Zn-ion batteries are promising devices but their energy storage mechanism remains elusive. Now it is shown that these involve a catalytic mechanism based on water dissociation.","PeriodicalId":18845,"journal":{"name":"Nature Catalysis","volume":null,"pages":null},"PeriodicalIF":42.8,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141319993","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 : 2024-06-14DOI: 10.1038/s41929-024-01177-6
Hendrik H. Heenen, Hemanth S. Pillai, Karsten Reuter, Vanessa J. Bukas
Electrocatalytic selectivity is often discussed at the atomic level on the basis of the active site, while ignoring more subtle effects of mesoscopic mass transport. Here we show how transport controls selectivity through the exchange of surface-bound reaction intermediates between the electrode and bulk electrolyte. We argue that the arising kinetic competition changes with the catalyst’s surface area and can become relevant for technologically important reactions including, for example, different products during the electrochemical CO2 reduction on Cu-based catalysts. Combining microkinetic and transport modelling in a multi-scale approach, we specifically explore and quantify this effect for various showcase examples in the experimental literature. Despite its simplicity, our model correctly reproduces selectivity trends with respect to catalyst roughness on all meso-, micro- and atomic scales. The resulting insight provides an alternative or, at least, complementary explanation to changes in electrocatalytic selectivity that have otherwise been attributed to nano-structuring of active sites or electronic effects due to doping or alloying. Mesoscopic mass transport is often ignored but it can influence electrocatalytic processes. This Analysis introduces a simple multi-scale model that couples diffusion to electrochemical surface kinetics and shows how mesoscopic mass transport determines product selectivity through catalyst morphology.
{"title":"Exploring mesoscopic mass transport effects on electrocatalytic selectivity","authors":"Hendrik H. Heenen, Hemanth S. Pillai, Karsten Reuter, Vanessa J. Bukas","doi":"10.1038/s41929-024-01177-6","DOIUrl":"10.1038/s41929-024-01177-6","url":null,"abstract":"Electrocatalytic selectivity is often discussed at the atomic level on the basis of the active site, while ignoring more subtle effects of mesoscopic mass transport. Here we show how transport controls selectivity through the exchange of surface-bound reaction intermediates between the electrode and bulk electrolyte. We argue that the arising kinetic competition changes with the catalyst’s surface area and can become relevant for technologically important reactions including, for example, different products during the electrochemical CO2 reduction on Cu-based catalysts. Combining microkinetic and transport modelling in a multi-scale approach, we specifically explore and quantify this effect for various showcase examples in the experimental literature. Despite its simplicity, our model correctly reproduces selectivity trends with respect to catalyst roughness on all meso-, micro- and atomic scales. The resulting insight provides an alternative or, at least, complementary explanation to changes in electrocatalytic selectivity that have otherwise been attributed to nano-structuring of active sites or electronic effects due to doping or alloying. Mesoscopic mass transport is often ignored but it can influence electrocatalytic processes. This Analysis introduces a simple multi-scale model that couples diffusion to electrochemical surface kinetics and shows how mesoscopic mass transport determines product selectivity through catalyst morphology.","PeriodicalId":18845,"journal":{"name":"Nature Catalysis","volume":null,"pages":null},"PeriodicalIF":42.8,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41929-024-01177-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141319858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-07DOI: 10.1038/s41929-024-01168-7
Caiwu Liang, Reshma R. Rao, Katrine L. Svane, Joseph H. L. Hadden, Benjamin Moss, Soren B. Scott, Michael Sachs, James Murawski, Adrian Malthe Frandsen, D. Jason Riley, Mary P. Ryan, Jan Rossmeisl, James R. Durrant, Ifan E. L. Stephens
Understanding what controls the reaction rate on iridium-based catalysts is central to designing better electrocatalysts for the water oxidation reaction in proton exchange membrane electrolysers. Here we quantify the densities of redox-active centres and probe their binding strengths on amorphous IrOx and rutile IrO2 using operando time-resolved optical spectroscopy. We establish a quantitative experimental correlation between the intrinsic reaction rate and the active-state energetics. We find that adsorbed oxygen species, *O, formed at water oxidation potentials, exhibit repulsive adsorbate–adsorbate interactions. Increasing their coverage weakens their binding, thereby promoting O–O bond formation, which is the rate-determining step. These analyses suggest that although amorphous IrOx exhibits a higher geometric current density, the intrinsic reaction rates per active state on IrOx and IrO2 are comparable at given potentials. Finally, we present a modified volcano plot that elucidates how the intrinsic water oxidation kinetics can be increased by optimizing both the binding energy and the interaction strength between the catalytically active states. Iridium oxide is the state-of-the-art catalyst for water oxidation in an acidic electrolyte. Now amorphous and crystalline iridium oxides are studied using operando time-resolved optical spectroscopy, together with other techniques, to reveal the nature and density of active centres and the role of adsorbate–adsorbate interactions.
{"title":"Unravelling the effects of active site density and energetics on the water oxidation activity of iridium oxides","authors":"Caiwu Liang, Reshma R. Rao, Katrine L. Svane, Joseph H. L. Hadden, Benjamin Moss, Soren B. Scott, Michael Sachs, James Murawski, Adrian Malthe Frandsen, D. Jason Riley, Mary P. Ryan, Jan Rossmeisl, James R. Durrant, Ifan E. L. Stephens","doi":"10.1038/s41929-024-01168-7","DOIUrl":"10.1038/s41929-024-01168-7","url":null,"abstract":"Understanding what controls the reaction rate on iridium-based catalysts is central to designing better electrocatalysts for the water oxidation reaction in proton exchange membrane electrolysers. Here we quantify the densities of redox-active centres and probe their binding strengths on amorphous IrOx and rutile IrO2 using operando time-resolved optical spectroscopy. We establish a quantitative experimental correlation between the intrinsic reaction rate and the active-state energetics. We find that adsorbed oxygen species, *O, formed at water oxidation potentials, exhibit repulsive adsorbate–adsorbate interactions. Increasing their coverage weakens their binding, thereby promoting O–O bond formation, which is the rate-determining step. These analyses suggest that although amorphous IrOx exhibits a higher geometric current density, the intrinsic reaction rates per active state on IrOx and IrO2 are comparable at given potentials. Finally, we present a modified volcano plot that elucidates how the intrinsic water oxidation kinetics can be increased by optimizing both the binding energy and the interaction strength between the catalytically active states. Iridium oxide is the state-of-the-art catalyst for water oxidation in an acidic electrolyte. Now amorphous and crystalline iridium oxides are studied using operando time-resolved optical spectroscopy, together with other techniques, to reveal the nature and density of active centres and the role of adsorbate–adsorbate interactions.","PeriodicalId":18845,"journal":{"name":"Nature Catalysis","volume":null,"pages":null},"PeriodicalIF":42.8,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41929-024-01168-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141287124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-05DOI: 10.1038/s41929-024-01173-w
Haocheng Xiong, Peiping Yu, Kedang Chen, Shike Lu, Qikun Hu, Tao Cheng, Bingjun Xu, Qi Lu
Electrochemical conversion of CO to chemicals containing C–N bonds offers an appealing route to store renewable electricity and mitigate CO2 emission, as CO2 can be efficiently transformed to CO. Previous electrocatalysis research has primarily focused on cathodic reactions, which are impeded by the competing hydrogen evolution reaction and limited electron efficiency. Here we present a urea synthesis approach via electrocatalytic oxidative coupling between CO and NH3 on commercial Pt catalysts. We demonstrate an optimal selectivity of approximately 70% for urea and remain above 50% throughout a wide potential window with an electrocatalytic C–N bond formation rate of up to 100 mmol h−1 gcatalyst−1. In mechanistic investigations, we propose that the oxidative coupling of CO and NH3 on Pt leads to cyanate formation, followed by the Wöhler reaction to form urea. This approach offers a practical route for urea production with high electron efficiency by enabling Pt-catalysed reactions between CO and NH3. Electrocatalytic urea formation most commonly involves the co-reduction of NOx species with CO2. This limits overall energy efficiency as commodity-scale NOx is produced from N2 via NH3. The swings in nitrogen oxidation state can be minimized through direct oxidative electrocatalytic reaction of CO and NH3 to urea, as shown in this study.
通过电化学方法将一氧化碳转化为含有 C-N 键的化学物质，可以有效地将二氧化碳转化为一氧化碳，从而为储存可再生能源电力和减少二氧化碳排放提供了一条极具吸引力的途径。以往的电催化研究主要集中在阴极反应上，而阴极反应受到氢进化反应的竞争和电子效率的限制。在此，我们提出了一种在商用铂催化剂上通过电催化 CO 和 NH3 氧化偶联合成尿素的方法。我们证明了尿素的最佳选择性约为 70%，并且在整个宽电位窗口内保持在 50% 以上，电催化 C-N 键形成率高达 100 mmol h-1 gcatalyst-1。在机理研究中，我们提出 CO 和 NH3 在铂上的氧化偶联导致氰酸酯的形成，然后发生沃勒反应生成尿素。这种方法通过铂催化 CO 和 NH3 之间的反应，为具有高电子效率的尿素生产提供了一条实用途径。
{"title":"Urea synthesis via electrocatalytic oxidative coupling of CO with NH3 on Pt","authors":"Haocheng Xiong, Peiping Yu, Kedang Chen, Shike Lu, Qikun Hu, Tao Cheng, Bingjun Xu, Qi Lu","doi":"10.1038/s41929-024-01173-w","DOIUrl":"10.1038/s41929-024-01173-w","url":null,"abstract":"Electrochemical conversion of CO to chemicals containing C–N bonds offers an appealing route to store renewable electricity and mitigate CO2 emission, as CO2 can be efficiently transformed to CO. Previous electrocatalysis research has primarily focused on cathodic reactions, which are impeded by the competing hydrogen evolution reaction and limited electron efficiency. Here we present a urea synthesis approach via electrocatalytic oxidative coupling between CO and NH3 on commercial Pt catalysts. We demonstrate an optimal selectivity of approximately 70% for urea and remain above 50% throughout a wide potential window with an electrocatalytic C–N bond formation rate of up to 100 mmol h−1 gcatalyst−1. In mechanistic investigations, we propose that the oxidative coupling of CO and NH3 on Pt leads to cyanate formation, followed by the Wöhler reaction to form urea. This approach offers a practical route for urea production with high electron efficiency by enabling Pt-catalysed reactions between CO and NH3. Electrocatalytic urea formation most commonly involves the co-reduction of NOx species with CO2. This limits overall energy efficiency as commodity-scale NOx is produced from N2 via NH3. The swings in nitrogen oxidation state can be minimized through direct oxidative electrocatalytic reaction of CO and NH3 to urea, as shown in this study.","PeriodicalId":18845,"journal":{"name":"Nature Catalysis","volume":null,"pages":null},"PeriodicalIF":42.8,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141251715","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 : 2024-06-03DOI: 10.1038/s41929-024-01167-8
Jiashun Liang, Shenzhou Li, Xuan Liu, Yangyang Wan, Yu Xia, Hao Shi, Siyang Zhang, Hsing-Lin Wang, Gang Lu, Gang Wu, Yunhui Huang, Qing Li
The preparation of noble metal nanowire electrocatalysts is greatly limited by the thermodynamically symmetric growth of face-centred-cubic structures. Here we report a gas-balancing adsorption strategy to prepare ultrathin palladium-, platinum- and gold-based nanowires (diameter < 2 nm) by controlling the competitive adsorption of in situ-generated H2 and CO. We prepare a library of 43 nanowires consisting of the three above-mentioned noble metals as hosts and 14 metals as guests. The ternary Pd85Pt8Ni7H41 nanowires with interstitial hydrogen exhibit impressive mass and specific activities of $$11.1 , {rm{A}},{rm{mg}}_{{rm{PGM}}}^{-1}$$ and 13.9 mA cm−2, respectively, for the oxygen reduction reaction at 0.9 VRHE in alkali. Operando X-ray absorption spectroscopy demonstrates breathing-like Pd–Pd bond length and strain changes at the applied potential, with Pd85Pt8Ni7H41 nanowires exhibiting larger compressive strain at relevant potentials, as well as low oxygen coverage. Theoretical calculations suggest that the interstitial hydrogen induces an s–d orbital interaction between palladium and hydrogen, which enhances the activity of the oxygen reduction reaction. The Pd85Pt8Ni7H41 nanowires can generate a high power density of 0.87 W cm−2 in H2/air (CO2-free) at 70 °C in an anion-exchange membrane fuel cell. Nanostructured design of mono- and multimetallic particles can be leveraged to achieve highly active catalysts. Now, a gas-balancing adsorption strategy is presented to prepare alloy nanowires with diameter of around 1 nm, whereby resulting catalysts achieve excellent performance for both anion- and proton-exhange membrane fuel cells.
贵金属纳米线电催化剂的制备受到面心立方体结构热力学对称生长的极大限制。在此，我们报告了一种气体平衡吸附策略，通过控制原位生成的 H2 和 CO 的竞争性吸附，制备超薄钯基、铂基和金基纳米线（直径为 2 nm）。我们制备了由上述三种贵金属作为主金属和 14 种金属作为客金属组成的 43 种纳米线。含有间隙氢的三元 Pd85Pt8Ni7H41 纳米线在 0.9 VRHE 碱条件下的氧还原反应中表现出令人印象深刻的质量活性和比活性，分别为 11.1 , {rm{A}}, {rm{mg}}_{{rm{PGM}}^{-1} 和 13.9 mA cm-2。操作性 X 射线吸收光谱显示，在施加的电位下，Pd-Pd 键的长度和应变发生了类似呼吸的变化，Pd85Pt8Ni7H41 纳米线在相关电位下表现出较大的压缩应变以及较低的氧覆盖率。理论计算表明，间隙氢诱导了钯与氢之间的 s-d 轨道相互作用，从而提高了氧还原反应的活性。在阴离子交换膜燃料电池中，Pd85Pt8Ni7H41 纳米线能在 70 °C 下的 H2/空气（无二氧化碳）中产生 0.87 W cm-2 的高功率密度。
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