Hierarchical Bimetallic Electrocatalyst with Amorphous SnO Layer for Highly Efficient Electroreduction of CO2.

Renewable electricity‐driven reduction of CO2 into value‐added chemicals has been recognized as a promising sustainable energy conversion method to achieve carbon‐neutrality. Although Sn‐based catalysts show excellent selectivity towards CO and HCOOH in CO2 reduction, the reaction activity, i. e. current density, remains quite low (<100 mA cm−2). Herein, a hierarchical bimetallic electrocatalyst consisting of Cu foam‐supported bundle‐like structure and thin amorphous SnO layer was fabricated for efficient electroreduction of CO2 to C1 products (CO and HCOOH). The hierarchical structure ensured higher large electrochemically active surface area, while the thin amorphous SnO layer could efficiently adsorb CO2, and stabilize the *CO2− intermediate formed in the rate‐determining step, thereby boosting the reaction activity of CO2 reduction. As a result, an unprecedented partial current density of 128.6 mA cm−2 was achieved for C1 products at −1.4 V vs. RHE with a Faradaic efficiency of 79.2 % in an H‐type cell. The strategy of integrating optimized structure with active site here may be beneficial to other related energy conversion systems. [ABSTRACT FROM AUTHOR]