Pd nanoparticle-decorated Bi₄O₅Br₂ nanosheets with enhanced visible-light photocatalytic activity for degradation of bisphenol A

Bismuth oxyhalides are important visible-light-responsive photocatalysts due to their unique electronic and layered crystal structure. In this study, Pd nanoparticles with the size of about 3–6 nm were loaded on the Bi₄O₅Br₂ nanosheets by applying solvothermal-reduction method. The photoelectrochemical performance and photocatalytic activity for the degradation of Bisphenol A in aqueous solution of Bi₄O₅Br₂ and Pd/Bi₄O₅Br₂ were evaluated. Compared with pure Bi₄O₅Br₂, Pd/Bi₄O₅Br₂ exhibited an excellent photocatalytic activity for the degradation of Bisphenol A in aqueous solution under LED visible light irradiation. 1.0 wt% loading of Pd was found to be most effective for improving the photocatalytic activity of Bi₄O₅Br₂ for the degradation of Bisphenol A and near to 95.8% of degradation was achieved after 70 min LED visible light irradiation. Under 535 and 630 nm monochromatic LED visible light irradiation for 70 min, only 7.9% and 4.8% Bisphenol A were degraded over 1.0% Pd/Bi₄O₅Br₂ photocatalysts, respectively. Therefore, the improved photocatalytic activity of Pd/Bi₄O₅Br₂ is mainly attributed to the formation of a Schottky barrier between the Pd nanoparticle and the Bi₄O₅Br₂ nanosheet, promoting efficient separation of photogenerated electrons and holes.