Improvement of catalytic activity in styrene oxidation of carbon-coated titania by formation of porous carbon layer
Abstract Porous carbon layer has been formed by treating the carbon-coated titania (C@TiO 2 ) with KOH solution. Carbon-coated titania (C@TiO 2 ) was obtained by pyrolysis of polystyrene-coated titania (PS@TiO 2 ), which was produced by in situ polymerization of styrene by using aqueous hydrogen peroxide. The presence of polystyrene and carbon on the surface of titania were confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy techniques. Carbon content was about 2.2 wt.% with thickness of carbon layer ca. 5 nm. After treating with KOH solution, PC@TiO 2 with the pore size of ca. 5 nm, total pore volume of 0.05 cm 2  g −1 and Brunauer–Emmett–Teller (BET) specific surface area of 46 m 2  g −1 has been obtained. Catalytic activity results showed that PC@TiO 2 gave a higher activity in styrene oxidation compared to bare TiO 2 , and C@TiO 2 . The highest catalytic activity was obtained by using PC@TiO 2 that obtained after treating C@TiO 2 with 1.0 M KOH solution with benzaldehyde and phenylacetaldehyde as the main reaction products. At the higher concentration of KOH solution, the catalytic activity decreased when crystallinity of TiO 2 decreased.