Facile flame thermal synthesis of SiO_x-C/ TiO₂microspheres with enhanced photocatalytic performance

Abstract

We report a very simple and novel photocatalyst synthetic strategy for the preparation of SiO x modified TiO2 microspheres and demonstrate their enhanced photocatalytic properties. The as-prepared samples were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectra. XRD results showed that anatase TiO2 was obtained directly without any post-heat treatment, and no obvious effect on the crystal structure was observed with the introduction of a small amount of SiO x . SEM images show microspherical morphology for the synthesized samples with a suitable amount of SiO x but irregular morphology was observed when higher content of SiO x was introduced. XPS results indicated that silicon existed in the forms of SiO2, SiO and Si2O3. Higher photocatalytic activity for the degradation of methylene blue (MB) under UV-vis light illumination was demonstrated with SiO x modification. The results indicated that the feasibility of MB degradation was not only due to morphological properties but also to the SiO x modification. Significantly, SiO x facilitates effective photodegradation through the increasing surface hydroxyl groups as traced by the FT-IR spectra for the resulting samples.