Construction of p-ZnBi2O4/n-BiOBr heterojunctions for efficient visible-light photocatalytic degradation of dyes

Abstract

A composite series, (1 − x)ZnBi₂O₄/x-BiOBr, was synthesized using a two-step hydrothermal method. The x = 0.7 composite demonstrated 100% removal of RhB in 10 minutes (k = 0.2317 min⁻¹) under visible light, ∼74 times higher than that of ZnBi₂O₄ (k = 0.0031 min⁻¹). For Orange G, x = 0.7 yielded 100% removal in 30 min with k = 0.1053 min⁻¹, ∼14 times greater than that of ZnBi₂O₄. The improved activity correlates with high S_BET (21.8 m² g⁻¹) and good interfacial charge separation. Band-edge estimates and scavenger tests suggested a type-II-like band alignment. Moreover, the x = 0.7 composite retained ≥81% of activity over 5 cycles.