Atomically dispersed tin in cuprous oxide for enhancing *CO coverage to selectively electroreduce CO2 toward C2 products

Abstract

The conversion of CO₂ into high-value chemicals using renewable electricity holds great application prospects. However, improving the selectivity toward C₂ products remains a challenge. Copper-based catalysts are capable of converting CO₂ into multicarbon products in the electrochemical CO₂ reduction reaction (CO₂RR), but they typically suffer from low *CO intermediate coverage, leading to sluggish C–C coupling kinetics and limited selectivity toward C₂ products. Here, we report a catalyst consisting of Sn atomically dispersed in a Cu₂O matrix (Sn–Cu₂O), synthesized via a facile one-pot method. The as-prepared catalyst Sn–Cu₂O-0.025 displays a faradaic efficiency of 73.2% for C₂ products, with ethanol accounting for 32.1%, at a current density of 200 mA cm⁻². Based on in situ FT-IR characterization, the introduction of Sn promotes the activation of CO₂ to *CO and enhances the coverage of *CO. The resulting increased coverage of *CO promotes the C–C coupling process, accelerates the formation of key intermediates *OCCOH, and ultimately enhances the selectivity toward C₂ products. This study provides insights into the utilization of Sn for modulating Cu-based catalysts to enhance the selectivity toward C₂ products during the CO₂ electroreduction reaction.