Carbon-coated anatase: adsorption and decomposition of phenol in water

Abstract

TiO2 particles of anatase structure were covered by thin layer of carbon through the mixing of commercially available powder TiO2ST-01 with poly(vinyl alcohol) (PVA) carbon precursor and heating at the high temperatures, 700 and 900°C and photodecomposition performance of phenol in water was studied. Porous carbon formed on TiO2 surface increased phenol adsorption on the catalyst but still decomposition rate of phenol was higher for the original TiO2 without carbon coating. Carbon layer covered on TiO2 particles suppressed anatase transformation onto rutile, depending on the mixing ratio of TiO2/PVA and temperature of heating. During heat treatment crystallinity of anatase phase was improved and the performance for phenol decomposition was improved, but still lower than original TiO2 without carbon coating. Carbon-coated TiO2 slowed down the process of decomposition by weakened the energy of UV rays coming to the TiO2 surface and diffusion of phenol to the active TiO2 surface. However these results showed, that the efficiency of prepared catalysts can be improved by chemical modification of activated carbon surface. The performance of carbon-coated anatase for photodecomposition of phenol was found to be governed mostly by the crystallinity of anatase phase but additionally also by the adsorption of phenol onto carbon layer coating anatase particles.