Lead-free perovskites have attracted considerable attention in photocatalytic hydrogen evolution due to their better moisture stability and lower toxicity than those of their lead-based analogues. However, their activity remains low and needs to be improved for practical applications. Properly engineered heterojunction photocatalysts can provide more active sites and stimulate efficient charge transfer. In this study, 1 T′/2 H−MoS2 nanoflowers were synthesized and coupled with tri(dimethylammonium) hexaiodobismuthate (DMA3BiI6) to form heterojunctions using a simple heating−cooling process. The synthesized 1 T′/2 H−MoS2/DMA3BiI6 composites exhibit excellent photocatalytic hydrogen evolution activity of hydroiodic acid splitting under visible-light irradiation with up to a rate of 241.5 µmol g⁻1 h⁻1 and apparent quantum efficiency of 11.2 % at 420 nm. Furthermore, a retained long-term performance stability after 3 days (12 cycles) of repeated hydrogen evolution reaction (HER) measurements was observed. Experimental and DFT studies indicate that the improved photocatalytic HER performance after the introduction of 1 T′/2 H−MoS2 on DMA3BiI6 is due to the efficient charge transfer and separation at the heterojunction interfaces in the composite. Accordingly, our work highlights a new potentially viable strategy to construct lead-free halide perovskite-based heterostructures for efficient photocatalytic HER.

1 T′/2 H MoS2 nanoflowers integrated with bismuth halide perovskite for improved photocatalytic hydrogen evolution