Electrochemically stable frustrated Lewis pairs on dual-metal hydroxides for electrocatalytic CO2 reduction

Abstract

The sluggish kinetics of CO₂ activation and reduction severely limit the energy conversion efficiency of electrocatalytic CO₂ reduction into fuels. Here, ZnSn(OH)₆ with an alternating arrangement of Zn(OH)₆ and Sn(OH)₆ octahedral units and SrSn(OH)₆ with an alternating arrangement of SrO₆ and Sn(OH)₆ octahedral units were adopted to check the effects of frustrated Lewis pairs (FLPs) on electrochemical CO₂ reduction. The FLPs were in situ electrochemically reconstructed on ZnSn(OH)₆ by reducing the electrochemically unstable Sn–OH to Sn–oxygen vacancies (Sn–O_Vs) as a Lewis acid site, which are able to create strong interactions with the adjacent electrochemically stable Zn–OH, a Lewis base site. Compared to SrSn(OH)₆ without FLPs, the higher formate selectivity of ZnSn(OH)₆ originates from the strong ability of FLPs to capture protons and activate CO₂via the electrostatic field of FLPs triggering better electron transfer and strong orbital interactions under negative potentials. Our findings may guide the design of electrocatalysts for CO₂ reduction with high catalytic performances.