Grain boundary and interface interaction Co-regulation promotes SnO2 quantum dots for efficient CO2 reduction

It is of great significance to explore the highly selective, excellent and stable electrocatalysts for electrochemical conversion of CO2 to hydrocarbons. Herein, we prepare SnO2 quantum dots (QDs) with abundant grain boundaries supported on MOF-derived hollow nitrogen-doped carbon (SnO2/NC) by a simple, low-cost, green method as an electrocatalyst for CO2 reduction. The obtained SnO2/NC exhibits high electrocatalytic performance for conversion of CO2 to formate with high selectivity. The Faradaic efficiency of formate (FEformate) formation is about 87.6 % at -1.13 V versus reversible hydrogen electrode (vs RHE). After 20 h electrolysis, the current density and FEformate of formate remains almost unchanged, showing significant stability. DFT calculations and experiments show that the strong interfacial interaction promotes the migration of electrons from the NC support to SnO2 QDs, which is beneficial to promote CO2 adsorption and activation to form *CO2-. Besides, SnO2 QDs have abundant grain boundaries to catalyze the conversion of CO2, and the porous structures are beneficial to improve the mass transfer rate and stability.