Pd nanoparticles decorated BiVO4 pine architectures for photocatalytic degradation of sulfamethoxazole

Sulfamethoxazole (SMX) has been extensively detected in wastewater treatment plant effluents and surface water. Because of its potential risks to ecology and health, treatment for eliminating SMX is urgently required. In this study, we report the application of Pd nanoparticles decorated on BiVO₄ pine architecture for the photocatalytic degradation of SMX. The results showed that the barer BiVO₄ and Pd-BiVO₄ eliminated SMX under visible-light irradiation. After 210 min of irradiation, 98.8% of SMX was substantially eliminated by Pd-BiVO₄, whereas bare BiVO₄ can degraded approximately 36.3% of SMX. Pd-BiVO₄ also exhibited a high mineralization rate (84% of total organic carbon (TOC) removal) compared to bare BiVO₄ (51% of TOC removal). Through three-dimensional excitation-emission matrix fluorescence spectra, SMX with high fluorescence intensity can be degraded to non-fluorescence intermediate products, further confirming the high mineralization of SMX over Pd-BiVO₄ catalyst. Well-dispersed Pd nanoparticles on the {040} facet of BiVO₄ pine architecture can support the recombination of photogenerated charge carriers because of the formation of the Schottky junction at the Pd-BiVO₄ interface. Besides, the active species trapping tests indicated that ^•O₂^- and h⁺ radicals dominate SMX photodegradation over Pd-BiVO₄. The main degradation intermediates of SMX in the reaction solution was also identified through ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis. This investigation can provide insight into designing metallic/semiconductor junctions for antibiotic elimination in water media.