Novel Z-scheme CuWO4/Cu/Cu2O heterojunction enhanced by LSPR effect for highly efficient visible-light-driven degradation of rifampicin

A novel Z -scheme CuWO 4 /Cu/Cu 2 O ternary heterojunction photocatalyst was successfully synthesized via a solvothermal approach, featuring the low-cost metallic copper (Cu) as an efficient electron mediator. This unique structure was designed to enhance Cu 2 O visible light capture capability and accelerate photogenerated charge separation, thereby efficiently degrading the recalcitrant antibiotic Rifampicin (RFP). Comprehensive characterizations (XRD, XPS, SEM, EDS) confirmed the successful construction of the heterojunction, where CuWO 4 and Cu particles are integrated onto the surface of the Cu 2 O. Compared to individual components and binary composites, the optimized CuWO 4 /Cu/Cu 2 O sample demonstrated significantly superior photocatalytic activity, achieving an impressive 88.0% RFP degradation rate within 80 min under visible light. The enhanced performance is primarily ascribed to the successful formation of a Z -scheme charge transfer pathway, where the localized surface plasmon resonance (LSPR) effect of the metallic Cu mediator promotes carrier migration, thereby improving both carrier separation efficiency and redox capacity. Kinetic analysis confirmed a degradation rate constant ( k ) of 0.02743 min −1 , approximately 2.8 times higher than that of pure Cu 2 O. Furthermore, the composite exhibited excellent stability, maintaining a degradation rate above 80% after five recycling runs and demonstrating robust performance across a broad pH range (3.0–7.0). Based on active species trapping and band structure analysis, a Z -scheme mechanism was proposed, highlighting O 2 − as the dominant active species. This study provides a facile and low-cost strategy for constructing highly efficient LSPR-enhanced Z -scheme photocatalysts for environmental remediation.