Abstract The electrochemical conversion of CO2 to formate still suffers from poor selectivity, low production rate, and high overpotential. In this study, a facile strategy is developed to obtain Bi catalysts with a hexagonal sheet structure on copper foil via the constant potential electrodeposition method. The electrocatalyst shows high activity for formate production from CO2 reduction, with the formate faradaic efficiency (FE) reaching nearly 100% at an overpotential of 0.65 V; a high production rate of 96.37 μmol· h−1·cm−2 is obtained, and the corresponding power consumption is as low as 3.64 kW·h·kg−1. The excellent catalytic ability is derived from the sharp edges and corner sites of the catalyst, as they provide numerous surface-active sites and increase the electrical conductivity and local electric field intensities of the surface electrode; thus, the electrochemically active surface area (ECSA) and the electron-donating ability of the Bi electrode are enhanced, while the competing hydrogen evolution reaction (HER) is significantly inhibited. Moreover, the Bi sheets show excellent stability in 24 h electrolysis, with a formate FE of ≥95.8% in aqueous 0.1 M KHCO3 solution. This work indicates that structural adjustment is a critical factor in enhancing the electrocatalytic performance of metallic Bi.

中文翻译：

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高选择性电化学 CO2 还原以在具有六边形片状结构的 Bi 催化剂上以低过电位进行甲酸盐化

摘要 CO2电化学转化甲酸盐的方法仍然存在选择性差、产率低和过电位高的问题。在这项研究中，开发了一种简便的策略，通过恒电位电沉积方法在铜箔上获得六边形片状结构的 Bi 催化剂。该电催化剂显示出通过 CO2 还原生产甲酸盐的高活性，在 0.65 V 的过电位下甲酸盐法拉第效率 (FE) 接近 100%；获得了96.37 μmol·h-1·cm-2的高产率，相应的功耗低至3.64 kW·h·kg-1。优异的催化能力源于催化剂锋利的棱角部位，因为它们提供了许多表面活性位点并增加了表面电极的电导率和局部电场强度；因此，Bi电极的电化学活性表面积（ECSA）和给电子能力得到增强，同时竞争性析氢反应（HER）受到显着抑制。此外，Bi 片在 24 小时电解中表现出优异的稳定性，在 0.1 M KHCO3 水溶液中甲酸盐 FE ≥95.8%。这项工作表明结构调整是提高金属铋电催化性能的关键因素。Bi 片在 24 小时电解中表现出优异的稳定性，在 0.1 M KHCO3 水溶液中甲酸盐 FE ≥95.8%。这项工作表明结构调整是提高金属铋电催化性能的关键因素。Bi 片在 24 小时电解中表现出优异的稳定性，在 0.1 M KHCO3 水溶液中甲酸盐 FE ≥95.8%。这项工作表明结构调整是提高金属铋电催化性能的关键因素。