Novel organic-inorganic Z-scheme heterojunction for enhanced photocatalytic hydrogen evolution coupled with selective oxidation of benzyl alcohol oxidation.

The development of a synergistic dual-functional photocatalyst for hydrogen (H) evolution and the value-added oxidation of benzyl alcohol (BA) is of great significance for both energy conversion and organic synthesis. In this study, a porous Z-scheme heterojunction photocatalyst (MnCd)(CNS)/MnCdS (MCTMT/MCS) was successfully constructed via a simple wet-chemical method combined with hydrothermal decomposition. By controlling the hydrothermal decomposition process, the specific surface area of the catalyst was significantly increased from 15.71 m/g to 202.77 m/g, which is conducive to the enhanced contact between reactant molecules and the surface of the photocatalyst, thereby increasing the probability of the photocatalytic reaction. Under visible light irradiation, the optimal MCTMT/MCS heterojunction exhibited outstanding photocatalytic performance, with an H₂ evolution rate of 1.42 mmol·g·h and a BA conversion rate exceeding 90 %, which is seventeen times higher than MCTMT. After 25 h of cyclic testing, the H₂ evolution rate remained at 1.12 mmol·g·h, significantly surpassing that of single-component catalysts. Moreover, UPS analysis elucidated the specific electron transfer pathway in the Z-scheme heterostructure of MCTMT/MCS, revealing that efficient charge separation and transfer significantly enhanced photocatalytic activity. This study provides valuable insights into the design of synergistic bifunctional metal sulfide photocatalysts for photocatalytic green H production and the synthesis of high value chemicals.