Synthesis of halloysite nanotubes supported Bi-modified BaSnO3 photocatalysts for the enhanced degradation of methylene blue under visible light

The novel Bi/BaSnO3@halloysite nanotubes (Bi/BaSnO3@HNTs) photocatalyst was successfully synthesized by precipitation-photoreduction method. Crystal structure, morphology, composition, optical property and band structure of photocatalysts were investigated by X-ray diffraction and transmission electron microscopy, scan-ning electron microscopy and Brunauer-Emmett-Teller technique, X-ray photoelectron spectroscopy and Fourier -transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy, and Mott-Schottky method, respectively. The catalytic activity of photocatalysts was evaluated by the removal efficiency of methylene blue solution under visible light irradiation. Among all samples, the Bi/ BaSnO3@HNTs catalyst presented the lowest carrier recombination and the best photocatalytic activity (90.2%). Meanwhile, a possible mechanism for the enhanced catalytic activity of Bi/BaSnO3@HNTs was proposed. The improved photocatalytic performance can be attributed to the surface plasmon resonance effect and the local electromagnetic field of metallic Bi, and the large specific surface area and strong adsorption capacity endowed by HNTs.