Enhanced electron transfer by In doping in SnO2 for efficient CO2 electroreduction to C1 products

Abstract

Electrocatalytic CO₂ reduction has received great attention for alleviating environmental problems and energy crisis. SnO₂-based catalysts are attractive candidates, but they still face problems such as high overpotentials and small current density due to their low intrinsic electrical conductivity and weak activation for CO₂. Here, superior selectivity and activity for C₁ products (HCOO⁻ and CO) were obtained using In-doped SnO₂. The maximum faradaic efficiency was 96.46% at −0.75 V and the partial current density reached −20.12 mA cm⁻² at −0.95 V for C₁ products. Furthermore, the selectivity for C₁ products was over 90% from −0.5 to −1.0 V with a current density of −166.2 mA cm⁻² at −1.0 V in flow cells. In ion doping induced electron transfer from Sn species to In and simultaneously generated oxygen vacancies, which improved electrical conductivity and regulated the oxidation state of Sn active sites and provided more active sites. This work emphasizes the role of enhanced electron transfer of catalysts in CO₂ electroreduction.