ABSTRACT A CO coverage-dependent Cu(100)/H2O interface model is used to study electroreduction pathways of CO2 towards C2H4 and CH3CH2OH products at the low overpotential with the aim of solving the long disputing on production mechanisms of C2 products. Our results show that previously predicted dimer OCCO may be not a viable intermediate and C-C coupling pathway may occur through reactions of COH with CO into COCOH and COH dimerization into COHCOH species on Cu(100). Thereby, the optimal CO2 electroduction pathways towards C2H4 and CH3CH2OH products can be presented. It is found that present defined CCHOH and CHCOH pathways both are favorable and may be able to occur parallelly during CO2 electroreduction into C2 products, naturally explaining why C2 products can be observed experimentally at low overpotentials on Cu(100). Thereinto, common CH2CH2OH and CHCH2 species can be formed in the parallel pathways wherein CHCH2 intermediate can directly lead to C2H4 product through proton-electron transfer process and CH2CH2OH species is the direct precursor into CH3CH2OH product. Mechanistic understanding towards the productions of C2 products on Cu(100) will open up routes to productions of high-energy fuels and provide significant insights into the design of highly active CO2 electroreduction catalysts operated at low overpotentials.

中文翻译：

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在低过电位下将 CO2 电还原为 C2 产物的机制：来自改进的电极/溶液界面模型的理论见解

摘要 为了解决长期以来对 C2 产品生产机制的争论，使用 CO 覆盖率相关的 Cu(100)/H2O 界面模型研究了 CO2 在低过电位下向 C2H4 和 CH3CH2OH 产品的电还原途径。我们的结果表明，先前预测的二聚体 OCCO 可能不是可行的中间体，CC 偶联途径可能通过 COH 与 CO 反应生成 COCOH 和 COH 二聚化为 Cu(100) 上的 COHCOH 物种而发生。因此，可以呈现出生成 C2H4 和 CH3CH2OH 产物的最佳 CO2 电导途径。发现目前定义的 CCHOH 和 CHCOH 途径都是有利的，并且可能能够在 CO2 电还原成 C2 产物的过程中并行发生，这自然解释了为什么可以在 Cu(100) 上的低过电位下通过实验观察到 C2 产物。其中，常见的 CH2CH2OH 和 CHCH2 物质可以在平行途径中形成，其中 CHCH2 中间体可以通过质子 - 电子转移过程直接导致 C2H4 产物，而 CH2CH2OH 物质是 CH3CH2OH 产物的直接前体。对在 Cu(100) 上生产 C2 产品的机理理解将开辟生产高能燃料的途径，并为设计在低过电位下运行的高活性 CO2 电还原催化剂提供重要见解。