In situ Irradiated XPS Investigation on S-Scheme TiO2@ZnIn2S4 Photocatalyst for Efficient Photocatalytic CO2 Reduction

Reasonable design of efficient hierarchical photocatalysts has gained significant attention. Herein, a step-scheme (S-scheme) core-shell TiO2@ZnIn2S4 heterojunction is designed for photocatalytic CO2 reduction. The optimized sample exhibits much higher CO2 photoreduction conversion rates (the sum yield of CO, CH3OH, and CH4) than the blank control, i.e., ZnIn2S4 and TiO2. The improved photocatalytic performance can be attributed to the inhibited recombination of photogenerated charge carriers induced by S-scheme heterojunction. The improvement is also attributed to the large specific surface areas and abundant active sites. Meanwhile, S-scheme photogenerated charge transfer mechanism is testified by in situ irradiated X-ray photoelectron spectroscopy, work function calculation, and electron paramagnetic resonance measurements. This work provides an effective strategy for designing highly efficient heterojunction photocatalysts for conversion of solar fuels.

Automated summary

Efficient hierarchical photocatalysts, such as the S-scheme core-shell TiO2@ZnIn2S4 heterojunction, have gained attention for photocatalytic CO2 reduction. The improved performance is attributed to the inhibited recombination of photogenerated charge carriers induced by the S-scheme heterojunction, as well as the large specific surface areas and abundant active sites. In situ irradiated X-ray photoelectron spectroscopy, work function calculation, and electron paramagnetic resonance measurements confirm the S-scheme photogenerated charge transfer mechanism.