Facile synthesis of N- and S-incorporated nanocrystalline TiO₂ and direct solar-light-driven photocatalytic activity

Abstract

Sulfur- and nitrogen-incorporated mesoporous TiO₂ (SNT) nanocomposites have been synthesized by a template-free homogeneous coprecipitation technique. The above nanocomposites have been thoroughly characterized by physicochemical and spectroscopy methods to explore the structural, electronic, and optical properties. The photocatalytic activities of the catalysts were evaluated for the degradation of methyl orange and phenol under direct solar light. SNT shows about a 2-fold higher photocatalytic activity than singly N-doped or S-doped mesoporous TiO₂ and 3-fold higher than Degussa P25. The higher activity might be attributed to the synergetic interaction of sulfate and nitrogen with the TiO₂ lattice. N-Ti-O and O-Ti-N-O environments are responsible for a red shift, and the sulfate group on TiO₂ acts as a cocatalyst, for increasing surface acidity as well as for sustaining the redox cycles for high stability.