N doping of TiO₂ nanocrystal for efficient photodegradation of organic pollutants under ultraviolet and visible light irradiation

Authors: XIAOYOU YU, QIANRUI LV

Abstract: To decrease the band gap of TiO₂ and enhance its photocatalytic performance, in this work, N-doped nanocrystalline TiO₂ is synthesized successfully through a simple sol-gel synthesis process with dicyandiamide used as N source. The N-doped TiO₂ photocatalysts have been characterized in detail by means of powder X-ray diffraction, Raman spectroscopy, infrared spectroscopy, UV-vis spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscope. The photocatalytic activities of N-doped TiO₂ to different organic pollutants are significantly different. Using 2 × 10^-5 mol/L methylene blue as the target pollutant, N-doped TiO₂ can produced approximately 100% conversion within 40 min, the photocatalytic degradation ability of which is equal or superior to commercial or bare TiO₂. The ameliorated photocatalytic activity of N-doped TiO₂ photocatalysts is attributed to the appropriate crystallinity, good dispersibility, modified Zeta potential, and increased absorption.

Keywords: Photocatalysis, nanocrystals, nitrogen doping, titanium oxide, organic pollutants

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