Regulating Electrocatalytic Performance of Cu <i> _x </i> Sn <i> _y </i> Aerogels on Carbon Dioxide Reduction by Tuning Cu/Sn Ratio

Abstract For advancing the electrochemical reduction of CO 2 (ECO 2 RR), the development of efficient electrocatalysts with high activity and selectivity is paramount and these properties are intrinsically linked to electronic structure and geometric morphology. In this work, Cu x Sn y bimetallic aerogels were fabricated via a facile NaBH 4 ‐mediated reduction method and the electrocatalytic activity of Cu x Sn y on ECO 2 RR was comprehensively investigated by electrochemical measurements, in situ characterization techniques and density functional theory (DFT) calculation. The results showed that the electrocatalytic performance of Cu x Sn y , especially the product selectivity is greatly influenced by the Cu/Sn ratio. In a flow electrolyzer, Cu 1 Sn 10 delivered an exceptional HCOOH production with 94% Faraday efficiency (FE) and a partial current density of 105.8 mA·cm −2 at −1.0 V vs. RHE, whereas Cu 15 Sn 1 favored CO generation with 90% FE and a partial current density of 171.2 mA·cm −2 , outperforming monometallic catalysts. Moreover, Cu x Sn y aerogels possessed a high current density and FE across a broad potential window and the attenuation was very low during 30 h stability tests. These excellent electrocatalytic properties benefited from the high porosity of aerogels which could enhance active site exposure and mass transfer efficiency and the bimetallic synergy which could regulate the electronic structure and adjust the adsorption or desorption strength of intermediates.