Cu-doped mesoporous SnO2 nanoparticles with rich grain boundaries and oxygen vacancies for photocatalytic CO2-to-CO conversion

Abstract

Photocatalytic conversion of carbon dioxide into fuels provides an effective approach to realize carbon resource utilization. However, the photocatalytic efficiency is still relatively low due to the recombination of photogenerated charges. Herein, we have designed Cu-doped SnO₂ nanoparticles (Cu–SnO₂) using a glucose-involved hydrothermal crystallization method for the photocatalytic reduction of CO₂. The rich oxygen vacancies facilitated the separation and transfer of photogenerated charges, and the confined effect of the typical mesoporous structure promoted the adsorption of CO₂, especially a high density of grain boundaries (GBs) and the doping of atomic Cu would introduce new active sites to activate CO₂ molecules. This elaborately designed catalyst exhibited super and stable photocatalytic conversion activity of CO₂-into-CO, with a CO optimal yield of 107 µmol g⁻¹ in 4 h, which was 2.75 times that over pure SnO₂. In situ Raman results indicated that the CO₂ reduction reaction followed a *COOH pathway on Cu–SnO₂. This work provides implications for the construction of a catalyst with rich defects in the field of energy and environmental catalysis.