Tuning Intermediate Binding Enables Selective Electroreduction of Carbon Dioxide to Carbon Monoxide on Copper-Indium Catalyst

Abstract

Electrosynthesis of carbon monoxide (CO) from carbon dioxide (CO₂) and water driven by renewable electricity represents a sustainable route to carbon upgrading, but the lack of cost-effective catalyst hinders its scaling-up. Here, we judiciously designed bimetallic Cu-In catalyst via in situ electroreduction of In-coated CuO nanowires. This facilely-prepared Cu-In catalyst delivers an excellent performance towards CO production in a flow cell, with a Faradaic efficiency of CO up to 91% at -69 mA cm^-2. In contrast to the previous studies suggesting that In-modified Cu strengthens the adsorption of *COOH and/or weakens the binding of *H, we revealed otherwise that the modification of In on Cu weakens the adsorption of CO and facilitates a faster desorption of CO from Cu, thus inhibiting C-C coupling process and leading to the suppressed formation of multi-carbon products, through a rigorous analysis of electrochemical reduction of CO, electrochemical adsorption of *CO and in situ Raman spectroscopy. Finally, we wired our CuIn-based electrolyzer with an efficient triple-junction solar cell for the demonstration of solar-driven CO₂ conversion and achieved a solar-to-chemical energy conversion efficiency of greater than 10% for CO.