Synthesis and characterization of Bi₂SiO₅-coated Ag/AgBr photocatalyst with highly efficient decontamination of organic pollutants

In this work, a novel nanoscale leaf-like ternary Bi₂SiO₅/Ag/AgBr photocatalyst was synthesized by means of the hydrothermal reaction together with an in situ photoreduction procedure. The ternary Bi₂SiO₅/Ag/AgBr composites possessed a neoteric heterostructure, in which the surface of AgBr was wrapped with nano-sheet Bi₂SiO₅. Through the coating of Bi₂SiO_5, the growth of AgBr nanoparticles was hindered, thereby inhibiting the agglomeration. In ternary composites, the particle size of Ag/AgBr obviously decreased, which reduced from 5 um to 0.6 um, approximately. The above effects of Bi₂SiO₅ on the morphology of Ag/AgBr were conducive to increasing the chance of contact between the active center and the reactant, thus promoting photocatalytic activity. Systematic researches showed that the BA 1–5 (the composite with a Bi₂SiO₅/Ag/AgBr molar ratio of 1:5) exhibited the optimal removal efficiency for RhB degradation, which was 5.97 times and 3.28 times that of Ag/AgBr and Bi₂SiO₅, respectively. Co-effect of the surface plasmon resonance (SPR) induced by Ag⁰ as well as formed heterojunction composed of Bi₂SiO₅, AgBr and Ag also contributed a lot in the splendid light absorption of ternary composites. H₂-TPR analysis indicated that the reduction ability of Ag/AgBr was further enhanced, comparing with that of bare Ag/AgBr. This present work can provide an original approach to devise and manufacture the Ag/AgBr-based photocatalysts.