Carbon doped ultra-small TiO2 coated on carbon cloth for efficient photocatalytic toluene degradation under visible LED light irradiation

The optimized C-USTiO2 photocatalysts on carbon cloth for a toluene degradation test at continuous toluene gas flow under LED light irradiation showed a superior toluene removal efficiency. [Display omitted] •USTiO2 with abundant active sites was obtained by a facile acid assisted solvent method.•Light absorption ability of C-USTiO2 was promoted through a carbon doping process.•Photo-generated electrons and holes of C-USTiO2 were separated efficiently.•Optimized C-USTiO2 exhibited superior toluene removal rate and robust stability under visible LED light irradiation. Photocatalytic activity triggered by visible light from light emitting diode (LED) is highly restricted by limited active sites, poor light absorption, and sluggish photo-generated carrier separation of the photocatalysts. Particularly for continuous degradation reaction of volatile organic compounds (VOCs), confined contact between flowing air pollutant gas and photocatalysts renders the degradation ineffective within a transient retention period. Considering the restriction of photocatalytic reaction occurred on semiconductor surface, ultra-small TiO2 (USTiO2) nanoparticles were fabricated by a facile acid-assisted solvent method, which possess copious active sites. A simple heating process was further applied for carbon doping on USTiO2 (C-USTiO2) surface. As a result, the obtained C-USTiO2 exhibited high visible light absorption, rich photo-generated carrier density, and its rapid carrier separation performance. In this study, optimized C-USTiO2 photocatalyst was deposited on carbon cloth and tested for continuous toluene degradation under LED light irradiation. Results showed that the toluene removal efficiency can reach higher than 80% with high concentration of CO2 generated and an excellent cycle stability of over 180 min.