Bismuth oxide iodide (BiOI), as a visible light semiconductor material, is widely utilized for photocatalytic removal of water pollutants. Nevertheless, due to its intrinsic high electron-hole pair recombination rate, bare BiOI typically exhibits limited photocatalytic performance. Bi5O7I shares similar crystal structures and identical elemental composition with BiOI, which could facilitate the formation of a stable interface when constructing a heterostructure between the two materials. In this study, a Z-scheme BiOI/Bi5O7I heterostructure was fabricated via an in situ thermal annealing strategy to suppress the recombination of photoexcited charge carriers and enhance the photo-oxidation activity of bare BiOI. The photoredox efficiencies of tetracycline and phenol were significantly improved after the formation of the heterostructure, which was mainly driven by the established Z-scheme charge carrier transfer mechanism. In virtue of the synergistic effect and the formed interface bonding between BiOI and Bi5O7I, the spatial separation of carriers and their subsequent transfer efficiency have been prominently enhanced, rendering the BiOI/Bi5O7I heterostructures possessed with a powerful photoredox capacity, thereby improving the photocatalytic activity of BiOI.
Shi et al. (2026) studied this question.