Efficient Degradation of Rhodamine B with the BiOCl/Bi2Fe4O9 Heterojunction Photocatalyst

BiOCl/Bi2Fe4O9 photocatalyst was prepared by a coprecipitation–hydrothermal method. The heterojunction structure generated by the composite of BiOCl and Bi2Fe4O9 reduced the electron–hole recombination efficiency and improved the degradation rate of RhB. At 240 min, 20% BiOCl/Bi2Fe4O9 represented the excellent degradation effect on 10 mg/L RhB; the degradation efficiency reached 99.56%; and the reaction rate constant was 0.01534 min–1, which was 5.76 times and 6.06 times that of Bi2Fe4O9 and BiOCl, respectively. The main active substance of the photocatalytic degradation of dyes was superoxide radical O2–·. Five cycles of the experiment proved the relative stability of BiOCl/Bi2Fe4O9.