Solvothermal synthesis of WO3 /TiO2 /carbon fiber composite photocatalysts for enhanced performance under sunlight illumination.

Carbon fiber (CF)-based WO3 /TiO2 composite catalysts (WO3 /TiO2 /CF) were successfully synthesized by solvothermal method. The catalysts were characterized by XPS, SEM, BET, XRD, FTIR, Raman and UV-Vis. The analyses confirmed the WO3 /TiO2 nanoparticles with high crystallinity deposited on the carbon structure. The photocatalytic degradation of Orange II azo dye under UV and sunlight illumination with the synthesized catalyst was explored. The composite catalyst displayed high performance (85%) for Orange II degradation while that of for WO3 /TiO2 was found as 76%. The effects of CF amount, solution pH, initial dye concentration and catalyst dose on photocatalytic performance were studied. It was found that the degradation efficiency increased from 68% to 90% with the increasing CF amount from 3 wt% to 5 wt%, while the further increase in CF amount (7-10 wt%) decreased the photodegradation due to the blocking the active sites of WO3 /TiO2 . The enhanced photocatalytic efficiency was mainly attributed to the electrical properties of the CF and reduced bandgap.