As a multiple proton-coupled electron transfer process, photocatalytic conversion of CO2 usually produces a wide variety of products. Improving the yield and selectivity of CO2 to the single product is still a significant challenge. In this work, we describe that the rationally constructed W18O49/Cu2O{111} interfaces achieve highly selective CO2 photocatalytic conversion to CH4. In situ Fourier transform infrared spectroscopy measurements reveal that the formation of W18O49/Cu2O{111} interfaces restrains the desorption of CO* intermediates in CO2 photocatalytic conversion. UPS spectra, PL spectra, and photocurrent curves show that more photogenerated electrons are excited and transferred to W18O49/Cu2O{111} interfaces. All of these play critical roles in CH4 production. As an outcome, the yield rate of CO2 photocatalytic conversion to CH4 was enhanced from 6.5 to 17.20 μmol g-1 h-1 with selectivity as high as 94.7%. The work demonstrates the feasibility and versatility of interface engineering in achieving highly selective CO2 photocatalytic conversion.
Keywords: CH4; CO* intermediate; CO2 photocatalytic conversion; W18O49/Cu2O{111} interfaces; interface engineering.