Transformation of flower-like sphere BiOBr to Bi₂O₂CO₃ by doping with urea and enhanced photocatalytic degradation of bisphenol A

Abstract

Bi-based catalysts can efficiently remove organic pollutants from the environment, but their performance still needs to be improved. Herein, BiOBr photocatalyst was prepared by one-step hydrothermal method, with bismuth nitrate and hexadecyl trimethyl ammonium bromide (CTAB) as precursors, and then BiOBr was transformed to Bi₂O₂CO₃ by the doping of urea. The structure and properties of the photocatalysts were characterized by SEM, TEM, XRD, XPS, UV–Vis, and BET, and the photocatalyst was used for the degradation of BPA. The results showed that the most economical doping amount of urea was 3 g, and the degradation rate of 10 mg/L BPA was 92.01% within 30 min at the catalyst dosage of 0.8 g/L, which was 1.98 times higher than that of pure BiOBr. The quenching experiments and ESR characterization indicated that $\cdot{\text{O}}_{2}^{-}$, h⁺ and ·OH were involved in the photocatalytic process, among which, the effect of $\cdot{\text{O}}_{2}^{-}$ was stronger than that of the other two active substances. Moreover, the degradation rate of BPA was still above 80% after four cycles, indicating that this photocatalyst is a highly efficient and stable material, which is expected to be applied in the environmental treatment and human health.