Surface Modification of Tin Dioxide via (Bi, S) Co-Doping for Photoelectrocatalytic Reduction of CO2 to Formate

Photoelectrocatalytic reduction of CO2 into useful fuels is a promising approach in terms of climate challenge and energy crisis. In this paper, a novel SnO2-based catalyst doped with bismuth (Bi) and sulfur (S) was synthesized via a simple hydrothermal method for photoelectrocatalytic reduction of CO2. The as-prepared catalyst demonstrates higher catalytic capability for CO2, in which the faradaic efficiency of formate reaches 55.6 % at an overpotential as low as similar to 360 mV and the maximum current density is close to 9.33 mA.cm(-2) at -1.4 vs Ag/AgCl with the doping ratio of 3 %, which is three times higher than pure SnO2. Meanwhile, the catalyst is more easily excited by visible light to reduce CO2 due to the narrowing of band gap. The notable electrocatalytic performance for CO2 reduction may be attributed to the defect caused by doping of Bi3+ and S2- into the lattice structure by replacing, respectively, Sn4+ and O2-. The catalyst may provide a novel strategy to promote the development of electrochemical reduction of CO2.