Adsorption and photocatalytic decomposition of organic molecules on carbon-coated TiO₂

Carbon-coated anatase TiO₂ samples were prepared from the mixture of poly vinyl alcohol (PVA) and commercial TiO₂ (P-25) with different mass ratios and heating temperatures. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive spectrometer (EDX), transmission electron microscope (TEM), and nitrogen adsorption analyses. The adsorption properties and photocatalytic activity of commercial and carbon-coated TiO₂ catalysts were compared for the oxidation of methylene blue (MB) and bisphenol-A (BPA). It was interesting to find that the transition from anatase to rutile was suppressed by carbon coating of TiO₂ at high temperature up to 800 °C. The carbon-coated TiO₂ samples have a higher surface area and a greater adsorption amount than commercial P-25 because of the thin layer of carbon that covered TiO₂. It was also observed that the photodecomposition efficiency was dependent on the crystallinity of the carbon-coated sample.