Halloysite nanotubes supported BiVO4/BaSnO3 p-n heterojunction photocatalysts for the enhanced degradation of methylene blue under visible light

The halloysite nanotubes (HNTs), which have a unique nanotube structure, are favorable for supporting BiVO4 and BaSnO3 nanoparticles. The p-n junctions at the interface between BiVO4 and BaSnO3 can contribute to the efficient separation of electrons and holes. In this study, the novel BiVO4/BaSnO3@HNTs composite was constructed by a facile precipitation method and the photocatalytic performance of photocatalysts was evaluated by the photocatalytic degradation efficiency of methylene blue (MB) dye. The results showed that BiVO4/BaSnO3@HNTs photocatalyst exhibited significantly enhanced catalytic efficiency for MB degradation (with decolorization rate of 94.1 % after 2 h of visible-light irradiation) in comparison with BiVO4，BaSnO3 and BiVO4/BaSnO3. The improved photocatalytic performance could be attributed to the rapid carrier separation induced by BiVO4/BaSnO3 p-n junctions, and the large specific surface area and adsorption capacity endowed by HNTs. Finally, based on the results of band structure of photocatalyst and electron spin resonance spectroscopy analysis, the possible charge transfer pathway across the BiVO4/BaSnO3 interface under visible light is discussed and a possible mechanism for the enhanced catalytic activity of BiVO4/BaSnO3@HNTs was proposed. [Display omitted]