Visible Light-Driven Rhodamine B Degradation and Mechanism Study of AgI/CuBi₂O₄/AgBr Z-Scheme Heterojunction Photocatalyst

Abstract

Organic water pollution threatens ecological safety, making the development of efficient and stable photocatalysts crucial for environmental remediation. This study addresses the issues of high carrier recombination rates and easy photodegradation in single semiconductors like CuBi₂O₄, AgBr, and AgI by designing a AgI/CuBi₂O₄/AgBr ternary Z-scheme heterojunction catalyst using co-precipitation. Characterization indicates that AgBr (layered) and AgI (spherical) are uniformly loaded on the surface of rod-shaped CuBi₂O₄, forming a close interface. Under visible light (λ > 420 nm), the catalyst achieves a 60-min degradation rate of 99.47% for 10 mg/L Rhodamine B, with a reaction rate improved by up to 120 times compared to single components. The activity remains at 83.9% after three cycles. Mechanism studies show that the Z-scheme heterojunction drives photo-generated electrons from AgBr/CuBi₂O₄ to the AgI conduction band, efficiently generating the dominant active species ·O₂⁻ (contribution rate 52.8%), while also inhibiting the photocorrosion of silver-based materials. This work optimizes carrier separation pathways through heterojunction interface engineering, providing a new strategy for the design of water treatment photocatalysts with both high activity and stability.