Preparation of Novel Layered High Entropy Bismuth-Based Materials and their Photocatalytic Degradation Mechanism

We prepared BiOCl, BiO(ClBr), BiO(ClBrI), and BiOClBrI(CO3)0.5 materials using a simple coprecipitation method. It was found that adjusting the number of anions in the anion layer was conducive to adjusting the band structure of BiOX and could effectively promote the migration and separation of photogenerated carriers, thus improving the photocatalytic activity. We first selected methyl orange (MO) as the study pollutant and compared it with BiOCl, BiO(ClBr), and BiO(ClBrI). The first-order kinetic constants of MO degradation by BiOClBrI(CO3)0.5 increased by 90.3, 33.9, and 3.1 times, respectively. The photocatalytic degradation rate of methylene blue by BiOClBrI(CO3)0.5 was 89.5%, indicating the excellent photocatalytic performance of BiOClBrI(CO3)0.5. The stability of BiOClBrI(CO3)0.5 was demonstrated through cyclic experiments and XRD analysis before and after the reaction. The photocatalytic degradation of MO by BiOClBrI(CO3)0.5 showed that h+ and 1O2 were the main active oxidizing species and •O2– was the secondary active substance. Overall, our work provides new ideas for the synthesis and degradation of organic pollutants by using two-dimensional anionic high-entropy materials.