Enhanced gas-phase photocatalytic oxidation of n-pentane using high visible-light-driven Fe-doped WO3 nanostructures

The main aim of this study was to investigate the photocatalytic potential of pure and Fe-doped WO3 nanoparticles for conversion of volatile organic compounds (VOCs). N-pentane, one of the n-alkanes VOCs, was selected as the pollutant model in gaseous phase. The used photocatalysts were synthesized by a facile method and characterized to determine the structural and optical properties. Results showed that the synthesized nanoparticles had small grain size with high crystallinity. The analyses of XRD, FTIR, and Raman exhibited that all doped and un-doped WO3 samples were in monoclinic form. The UV–vis and PL spectroscopies revealed that introducing Fe into WO3 led to narrowing band gap energy from 2.83 to 2.56 eV and decreasing the recombination rate of photo-generated electron-holes due to implanted defects and impurities in the host matrix. The photocatalytic experiments of n-pentane degradation were conducted in a self-design batch photo-reactor in the presence of O2 as oxidizing agent. The Fe-doped samples obviously exhibited the photocatalytic activity higher than the bare WO3. An almost full conversion of n-pentane, 99.91%, was provided without any catalyst deactivation by visible-light-irradiated 4.65 at.% Fe-doped WO3 which was 14.77% greater than that of the un-doped sample. Finally, a mechanism study was done based on the main intermediates detected using mass spectroscopy.