Atomic epitaxial heterojunction of BiOI for efficient Cr(VI) photocatalytic removal

Hao Xv, Jingxia Yang, Xuerong Zheng, Runkai Wang, Sangsook Park, Jihyeon Kim, Yida Deng, Jinguo Wang

https://doi.org/10.1016/j.seppur.2025.133918

https://authors.elsevier.com/a/1lGQZ4wbrTJFI6 (free access until August 03, 2025)

Abstract
The internal electric field of BiOI was improved by setting up an epitaxial heterojunction using solvothermal method. Ti/Zn/Cl elements were exchanged to BiOI nanosheets (BiOI-TZCl), which were homogeneously loaded on the top of BiOI surface without generating new crystalline phase. The Ti/Zn/Cl elements have changed the binding energy state of surface BiOI, and the resulted distinct layer structure in BiOI-TZCl nanosheets exhibited a changed energy band structure compared with pristine BiOI. The interfacial electric field of BiOI-TZCl can reach to 68.17 mV/nm, which is c.a. 25 folds improved compared to that of pure BiOI (2.73 mV/nm). This greatly improved the photo-induced charge generation and separation of BiOI-TZCl sample, which showed excellent behavior for Cr(VI) removal with high concentration (100 mg/L), especially under sunlight condition. The Cr(VI) removal rate reached to 2.96 mg·g−1·min−1 for per catalyst mass per minute. Additionally, BiOI-TZCl sample had high tolerance to anionic impurities and good recyclability.