Construction of hierarchical In2O3/In2S3-ZnCdS ternary microsphere heterostructures for efficient photocatalytic nitrogen fixation†

Photocatalytic ammonia production holds immense promise as an environmentally sustainable approach to nitrogen fixation. In this study, In₂O₃/In₂S₃-ZnCdS ternary heterostructures were successfully constructed through an innovative in situ anion exchange process, coupled with a low-temperature hydrothermal method for ZnCdS (ZCS) incorporation. The resulting In₂O₃/In₂S₃-ZCS photocatalyst was proved to be highly efficient in converting N₂ to NH₃ under mild conditions, eliminating the need for sacrificial agents or precious metal catalysts. Notably, the NH₄⁺ yield of In₂O₃/In₂S₃-0.5ZCS reached a significant level of 71.2 μmol g⁻¹ h⁻¹, which was 10.47 times higher than that of In₂O₃ (6.8 μmol g⁻¹ h⁻¹) and 3.22 times higher than that of In₂O₃/In₂S₃ (22.1 μmol g⁻¹ h⁻¹). This outstanding performance can be attributed to the ternary heterojunction configuration, which significantly extends the lifetime of photogenerated carriers and enhances the spatial separation of electrons and holes. The synergistic interplay between CdZnS, In₂S₃, and In₂O₃ in the heterojunction facilitates electron transport, thereby boosting the rate of the photocatalytic nitrogen fixation reaction. Our study not only validates the efficacy of ternary heterojunctions in photocatalytic nitrogen fixation but also offers valuable insights for the design and construction of such catalysts for future applications.