The electrochemical reduction of CO2 (CO2RR) mainly occurs at the three‐phase interface, and the properties of an interface can directly affect the CO2RR pathway. Cu‐based materials can produce considerable amounts of alcohols and hydrocarbons, but it is hard to precisely regulate the reaction interface and obtain specific target products. Herein, the properties of the Cu surface through a facile strategy of ionic liquid modification are successfully adjusted. According to theoretical calculations and in situ Raman and FTIR spectra characterizations, it is revealed that the introduction of ionic liquids (e.g., [Bmim][PF6]) can control the energy barriers and distribution density of key intermediates on Cu interface, thus totally change the reaction pathway of CO2 electroreduction. Consequently, the dominant products from the Cu catalyst will be dramatically switched between C2H4 with a 71.1% Faraday efficiency (FE) and CH4 with a 67.2% FE. It is rarely seen in previous reports that the CO2RR products can be fundamentally changed through simple interface modifications. This work offers a straightforward approach to tune the interfacial properties and understand the mechanisms in various electrocatalytic reactions.

中文翻译：

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铜反应界面上 CO2 电还原中离子液体诱导的产物转换

CO的电化学还原2（一氧化碳2RR）主要发生在三相界面，界面的性质可以直接影响CO2RR途径。铜基材料可以产生大量的醇和烃，但很难精确调控反应界面并获得特定的目标产物。在此，通过简单的离子液体改性策略成功地调节了铜表面的性质。根据理论计算以及原位拉曼和 FTIR 光谱表征，表明离子液体（例如 [Bmim][PF] 的引入6]）可以控制Cu界面上关键中间体的能垒和分布密度，从而彻底改变CO的反应途径2电还原。因此，Cu 催化剂的主要产物将在 C2H4法拉第效率 (FE) 和 CH 为 71.1%4FE 为 67.2%。在以往的报道中很少看到CO2通过简单的接口修改就可以从根本上改变RR产品。这项工作提供了一种直接的方法来调整界面特性并了解各种电催化反应的机制。