Selective electroreduction of CO2 to formate over the co-electrodeposited Cu/Sn bimetallic catalyst

Abstract Electrocatalysis is considered to be an effective method for carbon dioxide (CO 2) reduction to formate (HCOOH) and achieving renewable energy conversion. Unfortunately, limited by the high overpotential, low selectivity, and poor stability of the existing catalysts, the electrocatalytic CO2 reduction (CO2RR) is far from practical application. Herein, we designed a series of CuxSny (x, y are the molar ratio) bimetallic alloy catalysts by the co-electrodeposition strategy for electrocatalytic CO2RR to HCOOH generation. Bimetallic CuxSny catalysts are found to be more efficient than their monometal counterparts because of metal synergistic effects. In more detail, the Cu1Sn3-CC catalyst delivers high selectivity for HCOOH evolution of above 85% over a wide potential range (−0.8 V to −1.0 V vs. reversible hydrogen electrode [RHE]) with a low onset potential of −0.6 V vs. RHE and exhibits a Faradaic efficiency of 91.38% toward HCOOH generation and a maximum current density of 13.79 mA/cm2  at −0.8V vs. RHE. Furthermore, after long-term (36 h) operation, the Faraday efficiency of the catalyst is still higher than 88.35%. This work paves a facile way to synthesize novel bimetallic electrocatalysts for efficient production of HCOOH.