Selective Tandem CO2-to-C2+ Alcohol Conversion at a Single-Crystal Au/Cu Bimetallic Interface

Abstract

Copper-based bimetallic heterostructures have recently gained extensive attention because of their promising capability to steer the selectivity of electrochemical CO2 reduction into high-valued multicarbon products. However, a thorough mechanistic understanding toward the CO2 reduction pathway and the influence of interfacial atomic configuration has not yet been unveiled. Herein, we rationally engaged facet engineering to construct a Au/Cu heterostructure via an epitaxial growth and observed that Au(110)/Cu(110) exhibited the highest yield rate toward multicarbon alcohols, compared with results for Au(111)/Cu(111) and Au(100)/Cu(100). According to electrochemical analysis, the enhanced activity was attributed to high-conversion capabilities of both CO2-to-CO and *CO-to-C2+ alcohols. Moreover, we confirmed that the buildup of *CO is more crucial than the atomic arrangement of Cu surface for multicarbon production. Our work demonstrates a benchmark tandem CO2 electroreduction system to explicitly link the interfacial atomic configuration to the electrocatalytic performance and sheds light on the facet engineering of bimetallic electrodes in electrolysis.