Co-doped photocatalyst nanomaterials for effective utilisation of solar radiation

Abstract

Photocatalysis over metal oxide semiconductors is an effective way to reduce or eliminate the impact of aquatic and airborne pollutants. Titania (TiO2) photocatalyst is able to degrade many toxic and recalcitrant compounds under UV light illumination. Since UV light accounts for only about 5% of the solar energy, the more significant visible light fraction (45%) remains unused. Here we report the synthesis of non-metal (nitrogen) and metal/non-metal (silver/nitrogen) co-doped photocatalysts that are reactive both in the UV and visible range. Nitrogen doped and nitrogen/silver co-doped TiO2 nanoparticles were fabricated using a sol-gel production method at a relatively low temperature. The obtained gels were neutralised, washed with pure water, dried in oven, and calcined at 400 °C for 4 hours. Morphology changes were monitored using a scanning electron microscope. The photocatalysts were characterised by X-ray diffraction, X-ray photoelectron spectroscopy, and BET specific surface area. The results showed that spherical particles of anatase structure were produced after annealing at 400°C. The photocatalytic activity of these novel catalysts was investigated using a batch reactor system exposed to artificial solar irradiation. Both nitrogen and silver/nitrogen co-doped materials were effective in the photocatalytic degradation of hexamethyl pararosaniline chloride.