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

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 °C and 620 °C. The optimum calcination temperature and C content was 560 °C and 0.25 ± 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.

Figure optionsDownload high-quality image (262 K)Download as PowerPoint slideHighlights
► Carbon coated TiO2 was prepared by using ENR-50 as carbon precursor.
► Uniform thin graphitic C coating of 0.68 nm on TiO2 particles.
► Photocatalytic activity was greatly improved under 45-W fluorescent and solar light.
► Enhanced photocatalytic activity was due to low recombination of ecb− and h+.
► Possess stable photocatalytic efficiency over extended recycled applications.