Synergistically enhanced photothermal catalytic CO 2 reduction by spatially separated oxygen and sulphur dual vacancy regulated redox half-reactions

The conversion of carbon dioxide into chemical fuels via photocatalysis is a promising approach. However, the efficient separation of charge carriers and synchronous occurrence of redox half-reactions remained considerable obstacles. Here, S-scheme Bi 4 O 5 Br 2 /Cd 0.3 Zn 0.7 S with oxygen and sulfur double vacancies (V O,S ) was prepared by hydrothermal method. The spatial separation of oxidation half reaction and reduction half reaction was achieved by constructing of double active site of oxygen vacancies (V O ) in Bi 4 O 5 Br 2 and sulfur vacancies (V S ) in Cd 0.3 Zn 0.7 S. The CO generation rate of V O,S -15 %Bi 4 O 5 Br 2 /Cd 0.3 Zn 0.7 S (V O,S -CZBB) was 14.91 μmol g −1 h −1 in a gas-liquid-solid photothermal catalytic reduction, which was 7.23 times more than that of V S -Cd 0.3 Zn 0.7 S. Significantly, the S-scheme energy band structure can improve the harvesting of sunlight and enhance the separation and transfer of photogenerated carriers. In addition, V O,S on the surface of the V O,S -CZBB heterojunction facilitates the activation of CO 2 molecules. The results discuss the synergistic effects of the S-scheme energy band structure and V O,S on the photocatalyst and demonstrate the feasibility of spatially separated dual active sites in promoting the photocatalytic conversion of CO 2.