NH3 removal using the dielectric barrier discharge plasma-V-TiO2 photocatalytic hybrid system

This study investigates the photocatalytic performance of V-TiO2 for removal of highly concentrated ammonia (1,000 ppm) in the dielectric barrier discharge (DBD), plasma-photocatalytic, hybrid system. The V (1.0, 5.0, 10.0 mol-%)-TiO2 photocatalysts were prepared by using the conventional sol-gel method. Their surface areas were decreased with increasing vanadium component. The UV-visible absorption band slightly shifted to more visible wavelengths in V-TiO2 compared to that in pure TiO2. The NH3-TPD result confirmed that the ability of NH3 adsorption on the surface of V-TiO2 increased with increasing vanadium content, and was maximized for 5.0-mol% V-TiO2. The NH3 decomposition was enhanced with the photocatalyst compared to the decomposition rate without catalysts, while the decomposition was further increased with the applied plasma voltage. The NH3 decomposition reached 90% after 400 min at an applied plasma voltage of 10.0 kV, and various intermediates, such as -NH2, -NH, and NO, were also identified by using the Fourier transform infrared (FT-IR) spectra. In addition, the NH3 decomposition reached 100% in the plasma-5.0 mol% V-TiO2, photocatalytic, hybrid system after 25 min, compared to 98% in the pure V-TiO2 photocatalytic system after 150 min. In addition, the various undesirable byproducts were depressed when V-TiO2 photocatalyst was used compared to that in the non-catalytic system.