Improvement of efficiency and selectivity of CO2 photoreduction over Bi2O2SO4 catalysts with Cu-Bi alloys

Structural design of semiconductor photocatalysts plays an important role in promoting light absorption, molecular activation, and charge separation in the CO₂ reduction reaction, which is beneficial for improving photocatalytic activity. In this paper, a simple photodeposition strategy was employed to load Cu onto Bi₂O₂SO₄ and form a Cu-Bi alloy. Under simulated sunlight conditions, the optimal catalyst demonstrates impressive photocatalytic activity and selectivity for CO₂ reduction, with a corresponding yield of 18.8 μmol g^-1 h^-1, 15 times higher than that of pure Bi₂O₂SO₄, and CO selectivity reaching 97.1%. The results indicate that metal deposition enhances light absorption utilization efficiency and promotes the separation and transfer of photogenerated carriers. Additionally, the combination of in-situ FT-IR spectra and theoretical calculations reveal the molecular mechanisms of photocatalytic CO₂ reduction. This work discusses the synergistic effect of metal deposition and oxygen vacancies on photocatalytic reduction of CO₂, providing a feasible method for constructing metal deposition structures with defects.