Preparation and characterization of TiO2 coated with a thin carbon layer for enhanced photocatalytic activity under fluorescent lamp and solar light irradiations

摘要

Carbon (C) coated TiO2 with C content between 0.20% and 1.09% were prepared by calcination of various mixtures of TiO2 and epoxidized natural rubber (ENR-50) under N2 atmosphere between 470 亱C and 620亱C. The optimum calcination temperature and C content was 560亱C and 0.25亇0.01%, respectively with the estimated C coating thickness of 0.68 nm. The process did not change its BET surface area and induce any phase transformation. Photocatalytic activity of C coated TiO2 was better than pristine TiO2 for the degradation of anionic reactive red 4 (RR4) dye by more than 3 times, phenol by 1.1 times and cationic methylene blue (MB) by 1.5 times under a 45-W household fluorescent lamp irradiation while under solar irradiation, its photocatalytic activity with respect to pristine TiO2 improved by 5.5,3.5 and 2 times, respectively. Coating of more than 1% C on TiO2 changed its photocatalytic activity either at par or less than that of the pristine TiO2. The observed photocatalytic improvement was due to the significant decrease in the electron-hole recombination process as observed for the optimum C coated sample.