Bimetallic catalysts are widely used in electrochemical CO2 reduction reactions (ECRR). However, the study of structural effects of bimetallic catalysts on ECRR is still limited. Herein, two kinds of nitrogen-doped carbon-supported CuNi bimetallic catalysts with alloy structure (CuNi/NC-alloy) and phase-separated structure (CuNi/NC-PS) were prepared, respectively, and their ECRR performance were studied. Interestingly, compared with CuNi/NC-alloy, the unique phase separation structure in the CuNi/NC-PS catalyst made the d-band center of Ni the most moderate, balancing the bonding strength with *COOH and *CO, making it not only exhibited relatively low CO2 activation barrier but also not been poisoned by CO, thus exhibiting higher CO selectivity. Therefore, CuNi/NC-PS exhibited superior catalytic activity (−0.86 V vs. RHE, FECO = 94.03 %, jCO = 37.06 mA cm−2) compared to CuNi/NC-alloy. In the membrane electrode assembly, based on CuNi/NC-PS catalyst and Co/Mo metal–organic frameworks (Co/Mo-MOF) catalyst, the coupling of formaldehyde oxidation and CO2 reduction could save 22 % energy consumption at the current density of 100 mA cm−2 and obtain high value-added anode product HCOO−. This study will lay a foundation for understanding the structural effects of CuNi based bimetallic catalysts on their electrocatalytic activities.

中文翻译：

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释放 CuNi 双金属催化剂的潜力：用于高效电化学 CO2 还原的相分离设计的结构创新


双金属催化剂广泛用于电化学 CO2 还原反应 （ECRR）。然而，双金属催化剂对 ECRR 的结构影响的研究仍然有限。本文分别制备了两种具有合金结构（CuNi/NC合金）和相分离结构（CuNi/NC-PS）的氮掺杂碳负载CuNi双金属催化剂，并研究了它们的ECRR性能。有趣的是，与 CuNi/NC 合金相比，CuNi/NC-PS 催化剂中独特的相分离结构使 Ni 的 d 带中心最适中，平衡了与 *COOH 和 *CO 的键合强度，使其不仅表现出相对较低的 CO2 活化势垒，而且没有受到 CO 的毒害，从而表现出更高的 CO 选择性。因此，与 CuNi/NC 合金相比，CuNi/NC-PS 表现出优异的催化活性（-0.86 V vs. RHE，FECO = 94.03 %，jCO = 37.06 mA cm-2）。在膜电极组件中，基于 CuNi/NC-PS 催化剂和 Co/Mo 金属有机框架 （Co/Mo-MOF） 催化剂，甲醛氧化和 CO2 还原的耦合可在 100 mA cm−2 的电流密度下节省 22 % 的能耗，并获得高附加值的负极产品 HCOO−。本研究将为理解 CuNi 基双金属催化剂的结构效应对其电催化活性的影响奠定基础。