Visible light photo-treatment of simulated wastewater activated by high-efficient photocatalyst: A novel heterojunction of Bi2MoO6 balls and Pd nanoskeletons

Abstract

A novel Pd nano-skeleton (Pd NSs) modified Bi2MoO6 balls photocatalyst was prepared by a facile hydrothermal treatment. The characterization by multiple techniques demonstrated the excellent light absorption and effective photo-generated electron-hole pairs separation performance of the composite catalyst, which further proved its superior photocatalytic property. Compared to the pure Bi2MoO6 nanosheets, carbon quantum dots (CQDs) modified Bi2MoO6 balls and Pd nanoparticles (Pd NPs) modified Bi2MoO6 balls catalysts, 1.3% Pd NSs@Bi2MoO6 sample exhibited the optimal catalytic performance for removing methyl orange (MO), methylene blue (MB), K2Cr2O7, phenol and the simulated wastewater mixture formed by the first three above under the illumination of visible light. Above all, the degradation efficiency increased about 5 times that of the pure Bi2MoO6 balls for the degradation of MO. This great improvement was mainly attributed to Pd NSs with many contact edges, which provided more active sites for the adsorption reaction of organic dye molecules, following its better near-infrared light absorption capacity in the catalytic system. The active species mainly involved in the reaction were verified by ESR technique and the trapping test, mainly involving O2−, holes, OH, etc., and a possible photocatalytic reaction mechanism and pollutant degradation pathway were also proposed.