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 @ZnIn₂ S₄ heterojunction is designed for photocatalytic CO₂ reduction. The optimized sample exhibits much higher CO₂ photoreduction conversion rates (the sum yield of CO, CH₃ OH, and CH₄ ) than the blank control, i.e., ZnIn₂ S₄ 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.