CO2 reduction on metal-doped SnO2(110) surface catalysts: Manipulating the product by changing the ratio of Sn:O

The electrocatalytic carbon dioxide reduction reaction (CO2RR) producing HCOOH and CO is one of the most promising approaches for storing renewable electricity as chemical energy in fuels. SnO2 is a good catalyst for CO2-to-HCOOH or CO2-to-CO conversion, with different crystal planes participating the catalytic process. Among them, (110) surface SnO2 is very stable and easy to synthesisze. By changing the ratio of Sn:O for SnO2(110), we have two typical SnO2 thin films: fully oxidized (stoichiometric) and partially reduced. In this work, we are concerned with different metals (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au)-doped SnO2(110) with different activity and selectivity for CO2RR. All these changes are manipulated by adjusting the ratio of Sn:O in (110) surface. The results show that stochiometric and reduced Cu/Ag doped SnO2(110) have different selectivity for CO2RR. More specifically, stochiometric Cu/Ag-doped SnO2(110) tends to generate CO(g). Meanwhile, the reduced surface tends to generate HCOOH(g). Moreover, we also considered the competitive hydrogen evolution reaction (HER). The catalysts SnO2(110) doped by Ru, Rh, Pd, Os, Ir, and Pt have high activity for HER, and others are good catalysts for CO2RR.