Facile synthesis of high-performance indium nanocrystals for selective CO2-to-formate electroreduction

Selective electrocatalytic reduction of CO 2 to formate has received increasing interest for CO 2 conversion and utilization. Yet, the CO 2 reduction process still faces major challenges, partly due to the lack of cost-effective, highly active, selective and stable electrocatalysts. Here, we report a mesoporous indium ( mp -In) electrocatalyst composed of nanobelts synthesized via a simple solution-based approach for selective CO 2 reduction to formate. The mp -In nanocrystals provide enlarged surface areas, abundant surface active sites and edge/low-coordinated sites. Such advantages afford the mp -In with an outstanding electrocatalytic performance for the CO 2 -to-formate conversion. A high formate selectivity, with a Faradaic efficiency (FE) of >90% was achieved over a potential of −0.95 V to −1.1 V ( vs V RHE ). The mp -In catalyst showed excellent durability, reflected by the stable formate selectivity and current density over a 24 h reaction period. Density functional theory (DFT) calculations reveal that the stabilization of the intermediate OCHO* on the In-plane surfaces is energetically feasible, further elucidating the origin of its enhanced CO 2 -to-formate activity and selectivity. This work may offer valuable insights for the facile fabrication of porous hierarchical nanostructures for electrocatalytic and selective reduction of CO 2 .