Z-scheme heterojunction has been considered as one of the most promising light harvesting and charge separation materials for photocatalytic water splitting. However, a significant gap exists in the direct correlation of their heterostructure with photophysical and photocatalytic properties, preventing accurate prediction and informed design for further developing such photocatalysts for water splitting. To address this limitation, herein we report the synthesis and fundamental mechanistic studies of a newly designed Z-scheme ternary photocatalyst, V2O5/CdS/CoS2 (VCC). We show that this VCC heterostructure exhibits an excellent photocatalytic hydrogen evolution rate and stability, which are much better than those of a CdS/3% Pt heterostructure measured under the same conditions. More interestingly, using the combination of steady state emission spectroscopy, transient absorption spectroscopy, photocurrent density measurement, etc., we found that ultrafast hole transfer from CdS to V2O5 and electron transfer from CdS to CoS2 lead to efficient charge separation, which are responsible for the exceptional photocatalytic performance of VCC. This work not only provides a new strategy to construct a Z-scheme heterostructure with significantly improved performance and stability for hydrogen evolution reaction but also unravels the structure–property–function relationship in such a Z-scheme ternary structure, providing important insight on further developing robust and efficient photocatalysts for visible-light-driven water splitting.

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The transformation of the C=S group to the C=O group in thioureas or thiosemicarbazides of type (I) can be effected by grinding with aqueous H2O2. -(WANG*, X.; SONG, A.; ZHU, J.; YANG

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