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.