Defect-enriched (H₂PO^-₄, Cr³⁺)--Fe₂O₃/B-In₂S_{3 composites for visible light degradation of 4-nitrophenol}

In this work, the high-activity (H2PO4-, Cr3+)-alpha-Fe2O3 (PCF) with abundant oxygen vacancies (OVs) and the high specific area was obtained by co-adding H2PO4- and Cr3+. Defect-enriched PCF/beta-In2S3 composites were prepared by low-temperature hydrothermal processes. The prepared composites exhibited improved photocatalytic degradation of 4-nitrophenol under visible light irradiation. The SO bond between PCF and beta-In2S3 promoted the formation of tight heterojunction composites and increased the OVs concentration. Under the synergistic effect of photo-Fenton, defects, and heterojunction, the PCF/beta-In2S3 composites effectively promoted the separation of photogenerated carriers and accelerated the production of active substances (center dot OH, center dot O-2(-), O-1(2), and h(+)), leading to the improvement of photocatalytic-Fenton degradation performance. This work provided a new strategy for the preparation of highly efficient photocatalysts.