Reduced Graphene Oxide–Titanium Dioxide Nanocomposites: Structural Characterization and Photocatalytic Degradation of Gaseous Formaldehyde

Abstract

TiO2/rGO nanocomposites are prepared by the solvothermal process using titanium sulfate and graphene oxide (GO) as raw materials utilized for the photodegradation of gaseous formaldehyde. Characterization by Fourier‐transform infrared (FTIR) spectroscopy, Raman spectroscopy and X‐ray photoelectron spectroscopy (XPS) reveal that GO is partially reduced to reduced GO (rGO) and TiOC bond is formed between TiO2 and rGO. X‐ray diffraction (XRD) confirms that the presence of anatase TiO2. High‐resolution transmission electron microscopy (HRTEM) exhibits that TiO2 nanoparticles with a diameter of ≈20 nm are uniformly loaded on the wrinkled rGO sheets. UV‐vis spectroscopy reveals that the absorption intensity of TiO2/rGO increases with increasing GO content. Photoluminescence (PL) spectroscopy indicates that the ability of restraining electron–hole recombination initially increases with increasing GO content, followed by a gradual decrease. The TiO2/rGO nanocomposite (mTiO2:mGO = 40:1) demonstrates optimal photocatalytic performance with formaldehyde degradation rate of 96% in 2 h and stable activity, which can be ascribed to the larger reduction of GO (76.19%), higher TiOC bonds (17%), unfolded rGO sheets, and lower electron–hole recombination rate.