Highly selective reduction of CO2 to HCOOH by a ZnO/SnO2 electrocatalyst with heterogeneous interfaces

Sn-based catalysts are recognized as prospective electrocatalysts to produce HCOOH due to their environmental friendliness, low cost, abundant reserves and selective *OCHO adsorption. However, most Sn-based catalysts usually suffer from low selectivity, catalytic activity and high overpotential. Recently, heterojunctions have aroused great attention for their superiority in exploiting the advantages of different catalysts, coordinating the electronic structure and decreasing the activation energy barrier for better stability and activity. Herein, ZnO/SnO2 was designed and prepared for highly selective CO2 reduction for HCOOH. A Faraday Efficiency (FE) of 93.8% and a yield of 0.16 mmol h(-1) cm(-2) were obtained at the potential of -1.05 V. Experimental evidence showed that the excellent catalytic performance was attributed to the heterojunctions, which optimized the electronic properties, enhanced the adsorption of CO2 or CO2- and provided more active sites.