CO_2 Photocatalytic Reduction to Fuels: Enhanced Methanol Selectivity by Loading Ag on NaNbO_3

摘要

Pure and Ag-loaded NaNbO_3 were synthesized, and characterized by PL, Raman, XRD and FE-SEM. They were subsequently applied for the photocatalytic CO2 reduction to fuels process, wherein methanol and formic acid were detected. Loading silver significantly enhanced the methanol product selectivity over that of formic acid, which is economically-favorable since methanol is an energy-dense value-added fuel. We hypothesize that silver acts as an electrontrapping centre, which increases the surface electron density. The enhanced electron availability on silver possibly facilitates multi-electron transfers. The formation of methanol from CO_2 requires more electrons (6 e~-) than formic acid (2 e~-) per molecule of product formed, which likely accounts for the preferential formation of methanol over formic acid upon silver loading.