Ag-decorated 3D flower-like Bi2MoO6/rGO with boosted photocatalytic performance for removal of organic pollutants

A series of unique 3D flower-like Bi2MoO6(BMO)/reduced graphene oxide (rGO) heterostructured composites decorated with varying amounts of Ag nanoparticles (NPs) were fabricated. Their morphological characteristics, structural features, energy band structures and photoelectrochemical properties were systematically studied. All the Ag/BMO/rGO ternary composites (AgBG-y;y = 1%, 2% and 3%) demonstrated greater photocatalytic activity towards efficient removal of our selected organic models [methyl orange (MO), rhodamine B (RhB) and phenol], as compared with the BMO/rGO binary composites (BG-x;x = 0.25, 2, 4 and 5). Particularly, AgBG-2%, which was synthesized with the addition of 2 wt% rGO and 2 wt% Ag in BMO, possessed superior photocatalytic activity. The fitted rate constants (k) for the photocatalytic degradation of RhB, MO and phenol using AgBG-2% were estimated to be 0.0286, 0.0301 and 0.0165 min(-1), respectively, which were over one order of magnitude greater than those obtained using pure BMO. Several factors may contribute to the observed enhancement, including greater specific surface area, enhanced light absorption, promoted spatial separation of electron-hole (e(-)-h(+)) pairs and their suppressed recombination, especially benefiting from the synergistic effects among BMO, rGO and Ag NPs. Our work suggests that the rational design of BMO/rGO/Ag ternary composite was an effective strategy to boost the photocatalytic activity of the resulting catalyst towards the highly efficient removal of organic pollutants from water.