AgBr/Polyoxometalate/Graphene Oxide Ternary Composites for Visible Light-Driven Photocatalytic Hydrogen Production

Abstract

The exploration of high efficient and stable visible light-driven photocatalysts for water splitting into green energy hydrogen has been considered as one of the currently most challenging topics for solving the energy crisis and environmental remediation. In this paper, a series of ternary AgBr/polyoxometalate/graphene oxide (AgBr/POM/GO) composites (POMs = {PMo12}, {PW12}, {SiW12}, {P2W18}, and {P2Mo18}) were synthesized via an ionic liquid-assisted hydrothermal method. The successful combination of ternary AgBr/POM/GO composites has been determined by a series of techniques. In addition, such ternary nanocomposites displayed wide visible light absorption ranges. Photocatalytic experiments demonstrate that such AgBr/POM/GO ternary composites display remarkable photocatalytic activity for hydrogen production, and the photocatalytic performance can be regulated by the species of POMs. Under minimally optimized conditions, the average hydrogen evolution rates were 256.0 μmol g–1 h–1 for AgBr/PMo12/GO, 223.2 μmol g–1 h–1 for AgBr/PW12/GO, 212.0 μmol g–1 h–1 for AgBr/SiW12/GO, 207.2 μmol g–1 h–1 for AgBr/P2W18/GO, and 177.2 μmol g–1 h–1 for AgBr/P2Mo18/GO, respectively. Both AgBr and POMs can be excited under the irradiation, greatly improving the visible light adsorption of the nanocomposites. Moreover, the adoption of POMs enhances the photochemical performance of the ternary nanocomposites because of their excellent redox properties and good photogenerated-electron/holes generation capacities. This work presents an efficient POM-based photocatalyst system for photocatalytic hydrogen production, which may provide important guidance for the design and exploration of efficient photocatalytic materials.