Hierarchical Z-scheme photocatalyst of g-C3N4@Ag/BiVO4 (040) with enhanced visible-light-induced photocatalytic oxidation performance

Abstract

The preferred exposure of (040) crystal facet of BiVO4 is conductive to optimizing its photocatalytic performance. And the great separation of photoinduced electron-hole pairs is also a critical factor for semiconductor photocatalyst. Herein we designed a hierarchical g-C3N4@Ag/BiVO4 (040) hybrid photocatalyst, in which Ag was photodeposited on the (040) facets of BiVO4 and subsequently g-C3N4 was covered on the surface of Ag/BiVO4 (040). The physical and chemical properties of the synthetic samples were analyzed by several characterization techniques. SEM spectrum clearly reveals the morphology and structure of g-C3N4@Ag/BiVO4 (040), suggesting the existence of the hierarchical composite photocatalyst. The visible light absorption wavelength of the composite is increased due to the surface plasmon resonance (SPR) effect of metal Ag nanoparticles, displayed in UV–vis spectrum. The photogenerated electron-hole pairs are also greatly enhanced through the Z-scheme g-C3N4@Ag/BiVO4 (040) system with the Ag nanoparticles as the electron mediator. The above synergistic effects of the hybrid photocatalyst result in higher photocatalytic oxidation performance not only for water splitting but also for NO oxidation in gas phase compared with pure BiVO4.