Effect of urea addition on anatase phase enrichment and nitrogen doping of tio2 for photocatalytic abatement of methylene blue

Abstract

TiO2-based materials are commonly employed as photocatalysts for industrial wastewater treatment. The primary reasons of employing TiO2 include cost effectiveness, ready availability, eco-friendliness, non-toxic behavior, and exceptional resistance towards photo-corrosion. However, the wider band gap of pure TiO2 restricts its performance because of its optical absorption of solar light to the ultraviolet (UV) region only, and to some extent of photo-excited charge recombina-tion. In the present work an attempt is made to develop a facile synthesis approach by using urea, a cheap chemical precursor, to form nitrogen doped TiO2 with the key objective of extended light absorption and thus enhanced photocatalytic performance. It was also observed that the urea-induced anatase phase enrichment of TiO2 is another key factor in promoting the photocatalytic perfor-mance. The photocatalysts prepared by varying the amount of urea as a nitrogen dopant precursor, are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier trans-form infrared (FTIR) spectroscopy, and photoluminescence (PL) to evaluate their crystallinity, mor-phology, functional groups, and charge separation properties, respectively. Moreover, the surface area was also estimated by physicochemical adsorption. The maximum nitrogen-doped sample yielded >99% photodegradation efficiency of methylene blue (MB) dye-simulated wastewater as compared to a pure TiO2 sample which exhibited 6.46% efficiency. The results show that the simulta-neous factors of nitrogen doping and anatase phase enhancement contributes significantly towards the improvement of photocatalytic performance.