Thiolate‐protected Cu clusters with well‐defined structures and stable low‐coordinated Cu+ species exhibit remarkable potential for the CO2RR and are ideal model catalysts for establishing structure–electrocatalytic property relationships at the atomic level. However, extant Cu clusters employed in the CO2RR predominantly yield 2e− products. Herein, two model Cu4(MMI)4 and Cu8(MMI)4(tBuS)4 clusters (MMI = 2‐mercapto‐1‐methylimidazole) are prepared to investigate the synergistic effect of Cu+ and adjacent S sites on the CO2RR. Cu4(MMI)4 can reduce CO2 to deep‐reduced products with a 91.0% Faradaic efficiency (including 53.7% for CH4) while maintaining remarkable stability. Conversely, Cu8(MMI)4(tBuS)4 shows a remarkable preference for C2+ products, achieving a maximum FE of 58.5% with a C2+ current density of 152.1 mA∙cm−2. In situ XAS and ex situ XPS spectra reveal the preservation of Cu+ species in Cu clusters during CO2RR, extensively enhancing the adsorption capacity of *CO intermediates. Moreover, kinetic analysis and theoretical calculations confirm that S sites facilitate H2O dissociation into *H species, which directly participate in the protonation process on adjacent Cu sites for the protonation of *CO to *CHO. This study highlights the important role of Cu–S dual sites in Cu clusters and provides mechanistic insights into the CO2RR pathway at the atomic level.

中文翻译：

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通过原子级精确的硫醇盐保护的铜簇中的硫增强质子进给促进 CO2 电还原为碳氢化合物产品


硫醇盐保护的铜簇具有明确的结构和稳定的低配位 Cu+ 物种，在 CO2RR 方面表现出巨大的潜力，是在原子水平上建立结构-电催化性能关系的理想模型催化剂。然而，CO2RR 中使用的现有 Cu 簇主要产生 2e− 产物。在此，制备了两个模型 Cu4(MMI)4 和 Cu8(MMI)4(tBuS)4 簇（MMI = 2-mercapto-1-methylimidazole）来研究 Cu+ 和相邻 S 位点对 CO2RR 的协同作用。 Cu4(MMI)4 可以将 CO2 还原为深度还原产物，法拉第效率为 91.0%（其中 CH4 为 53.7%），同时保持显着的稳定性。相反，Cu8(MMI)4(tBuS)4 对 C2+ 产品表现出显着的偏好，在 C2+ 电流密度为 152.1 mA∙cm−2 时实现了 58.5% 的最大 FE。原位 XAS 和异位 XPS 光谱揭示了 CO2RR 过程中 Cu 簇中 Cu+ 物质的保存，大大增强了 *CO 中间体的吸附能力。此外，动力学分析和理论计算证实，S位点促进H2O解离成*H物种，*H物种直接参与相邻Cu位点上的质子化过程，将*CO质子化为*CHO。这项研究强调了 Cu 团簇中 Cu-S 双位点的重要作用，并提供了原子水平上 CO2RR 途径的机制见解。