Preparation and characterization of BiOCl/TiO₂/MMT composite materials

To broaden the light response range of TiO₂ and improve its photocatalytic activity, BiOCl/TiO₂/MMT composite materials (BTMC) with outstanding photocatalytic performance were prepared by the sol-gel method with montmorillonite (MMT) as the supporting material, tetrabutyl titanate as titanium source and, bismuth nitrate pentahydrate as the bismuth source. The properties of the prepared materials were characterized by X-ray diffractometer (XRD), surface and porosity analysis (BET), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), and ultraviolet-visible diffuse reflection spectroscopy (UV-Vis DRS). When the Bi/Ti molar ratio was 20%, the composite material exhibited a slit mesoporous structure, and its specific surface area was 109.02 m²/g, with optimum photocatalytic activity. TiO₂ and BiOCl formed the type-II heterojunction on the surface of MMT, which facilitates the transfer of photogenerated electrons and holes, thus enhancing the photocatalytic activity of BTMC-20. The results of this study indicated that BTMC-20 is a promising photocatalytic composite material and has better photocatalytic properties under visible light.