Recent developments of copper (Cu)-based nanomaterials have enabled the electroreduction of CO₂ at low overpotentials. The mechanism of low-overpotential CO₂ reduction on these nanocatalysts, however, largely remains elusive. We report here a systematic investigation of CO₂ reduction on highly dense Cu nanowires, with the focus placed on understanding the surface structure effects on the formation of *CO (* denotes an adsorption site on the catalyst surface) and the evolution of gas-phase CO product (CO(g)) at low overpotentials (more positive than −0.5 V). Cu nanowires of distinct nanocrystalline and surface structures are studied comparatively to build up the structure–property relationships, which are further interpreted by performing density functional theory (DFT) calculations of the reaction pathway on the various facets of Cu. A kinetic model reveals competition between CO(g) evolution and *CO poisoning depending on the electrode potential and surface structures. Open and metastable facets such as (110) and reconstructed (110) are found to be likely the active sites for the electroreduction of CO₂ to CO at the low overpotentials.

中文翻译：

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在铜纳米线上将CO ₂低电势还原为CO的机理研究。

铜（Cu）基纳米材料的最新发展已使CO ₂在低过电势下发生电还原。然而，在这些纳米催化剂上低过剩CO ₂还原的机理仍然难以捉摸。我们在这里报告对CO ₂的系统研究还原高密度铜纳米线，重点是了解表面结构对* CO形成的影响（*表示催化剂表面的吸附位置）和气相CO产物（CO（g））的释放低过电位（高于-0.5 V的正电压）。对具有不同纳米晶体和表面结构的Cu纳米线进行了比较研究，以建立结构与性质之间的关系，通过在Cu的各个面上执行反应路径的密度泛函理论（DFT）计算，可以进一步解释这种关系。动力学模型揭示了取决于电极电势和表面结构的CO（g）释放与* CO中毒之间的竞争。发现诸如（110）和重建的（110）之类的开放且亚稳态的小面很可能是CO电还原的活性位点在低超电势下，CO的浓度为₂。