Abstract：
Although many catalysts have been reported for the CO2 electroreduction to C1 or C2 chemicals, the insufficient understanding of fundamental correlations among different products still hinders the development of universal catalyst design strategies. Herein, we first discover that the surface *CO coverage is stable over a wide potential range and reveal a linear correlation between the partial current densities of CH4 and C2 products in this potential range, also supported by the theoretical kinetic analysis. Based on the mechanism that *CHO is the common intermediate in the formation of both CH4 (*CHO → CH4) and C2 (*CHO + *CO → C2), we then unravel that this linear correlation is universal and the slope can be varied by tuning the surface *H or *CO coverage to promote the selectivity of CH4 or C2 products, respectively. As proofs-of-concept, using carbon-coated Cu particles, the surface *H coverage can be increased to enhance CH4 production, presenting a high CO2-to-CH4 Faradaic efficiency ( [Formula: see text] ∼52%) and an outstanding CH4 partial current density of -337 mA cm-2. On the other hand, using an Ag-doped Cu catalyst, the CO2RR selectivity is switched to the C2 pathway, with a substantially promoted [Formula: see text] of 79% and a high partial current density of -421 mA cm-2. Our discovery of tuning intermediate coverages suggests a powerful catalyst design strategy for different CO2 electroreduction pathways.
摘要：
尽管已经报道了许多催化剂用于将CO2电还原为C1或C2化学品，对不同产品之间基本相关性的理解不足仍然阻碍了通用催化剂设计策略的发展。在这里，我们首先发现，表面*CO覆盖率在很宽的电位范围内是稳定的，并揭示了CH4和C2产品在这个电位范围内的部分电流密度之间的线性关系，也得到了理论动力学分析的支持。基于*CHO是CH4（*CHO→CH4）和C2（*CHO*CO→C2）形成的共同中间体的机制，然后，我们揭示了这种线性相关是普遍的，斜率可以通过调整表面*H或*CO覆盖率来改变，以促进CH4或C2产物的选择性，分别。作为概念证明，使用碳涂层的铜颗粒，表面*H覆盖率可以增加，以提高CH4的产量，呈现高CO2至CH4的法拉第效率（[公式：见正文]52%）和出色的CH4部分电流密度-337mAcm-2。另一方面,使用Ag掺杂的Cu催化剂，CO2RR选择性切换到C2途径，具有79％的基本提升的[公式：参见正文]和-421mAcm-2的高部分电流密度。我们对调节中间覆盖率的发现表明了针对不同CO2电还原途径的强大催化剂设计策略。
