Photocatalytic Degradation of Congo Red Using an S-scheme Heterojunction Photocatalyst Based on Bismuth Compounds

Abstract

A BiOI/BiOBr S-scheme heterojunction photocatalyst was synthesized using a solvothermal method, and its ability to degrade Congo red was thoroughly investigated. The photocatalytic performance of the BiOI/BiOBr heterojunction was compared with that of pure BiOBr and BiOI. The structural, morphological, optical, and electrical properties of the samples were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), and zeta potential analysis. The degradation rate of Congo red was determined by spectrophotometry, revealing that the BiOI/BiOBr S-scheme heterojunction exhibited excellent photocatalytic performance, achieving a degradation rate of 96.8% for a 50 mg/L Congo red solution within 75 minutes. This rate was significantly higher than those achieved by pure BiOBr (77.2%) and BiOI (83.1%). Theoretical calculations indicate that the S-scheme heterojunction effectively facilitates the separation of photogenerated charge carriers while preserving the strong redox ability of the composite. These characteristics are identified as the key factors underlying the superior photocatalytic degradation efficiency of the BiOI/BiOBr S-scheme heterostructure.

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Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature