Understanding rich oxygen vacant hollow CeO2@MoSe2 heterojunction for accelerating photocatalytic CO2 reduction

Solar-driven CO2 reduction into gas fuels is desirable for a sustainable carbon cycle. To improve the photocatalytic activity of CO2RR, the unique rich oxygen (Vo) vacant hollow CeO2@MoSe2 is designed. The introduction of Vo is conducive to the capture of electrons by CO2 and promotes the process of photocatalytic CO2RR. The heterojunction formed by introducing the narrow band gap semiconductor MoSe2 increases the absorption range of visible light and improves the separation efficiency of photogenerated carriers. The hollow structure improves the CO2 adsorption capacity and improves the use of light effect. Therefore, the prepared H-Vo-CeO2@49.7 wt% MoSe2 exhibits enhanced photocatalytic activity for CO2RR. The yield of CH4 and CO is 10.2 µmol and 33.2 µmol in 4 h. Moreover, the photocatalytic mechanism is discussed through DFT and in-situ DRIFTS. This work provides new insights to the role of Vo in active CO2 photoconversion and exploits an important application of CO2 reduction.