Construction of BiPO₄/CdS heterojunction photocatalysts for enhanced degradation of organic pollutants under visible light

In this study, the composite of CdS nanorods loaded with BiPO₄ nanoparticles was fabricated as a novel efficient photocatalyst and exhibited strong photocatalytic degradation activities for the degradation of organic pollutants. Among the composites with different mass ratios, 1.8BiPO₄/CdS showed the best catalytic activity, and the removal rates of malachite green (MG), reactive red (X-3B) and ciprofloxacin (CIP) in 80 min were 98%, 99%, and 70%, respectively. The COD removal efficiencies of MG (55%), X-3B (50%) and CIP (44%) by 1.8BiPO₄/CdS composites further proved the superiority of the performance of BiPO₄/CdS heterojunctions under visible light. About 90% MG, 88% X-3B and 58% CIP could be degraded after four cycles indicating the good stability of the materials. The enhanced photocatalytic properties can be attributed to the efficient charge separation as well as interfacial charge transfer from CdS to BiPO₄, which is evidenced by XPS analysis and species trapping. The well dispersion of BiPO₄ on CdS can preserve it from photocorrosion, which effectively enhances the photostability of degradation properties. Moreover, several recommendations and ideas are proposed for improving the utilization of solar energy and environmental restoration in the future.