Effect of anisotropic conductivity of Ag2S-modified ZnmIn2S3+m (m = 1, 5) on the photocatalytic properties in solar hydrogen evolution
3 wt% Ag2S/Zn5In2S8 (3A/Z5) and 3 wt% Ag2S/ZnIn2S4 (3A/Z1) were prepared by a two-step synthesis method. The first-principles calculations revealed that the anisotropic carrier transport property of Zn5In2S8 (Z5) is much stronger than that of ZnIn2S4 (Z1). Furthermore, unsynchronized electron and hole transport leads to higher bulk carrier separation efficiency in Z5. After accelerating the surface photocatalytic reaction rate by Ag2S modification, the differences between 3A/Z5 and 3A/Z1 in the bulk carrier separation were further enlarged. Photoelectrochemical tests confirmed that the bulk charge separation efficiency of 3A/Z5 is 13.70%, which is 7.4 times higher than 3A/Z1 (1.84%). Because of the high bulk carrier separation efficiency, the 3A/Z5 exhibits a promising photocatalytic hydrogen production rate, reaching 3189 μmol h−1 g−1. Through intuitive evidence, this work proves that material with stronger anisotropic conductivity has higher bulk carrier separation efficiency, thus has the potential to exhibit high photocatalytic hydrogen production performance.
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