Rapid Synthesis of C-TiO2: Tuning the Shape from Spherical to Rice Grain Morphology for Visible Light Photocatalytic Application

Visible light-active carbon-loaded anatase TiO2 (C-TiO2) nanocrystals of spherical, distorted spherical, rice grain and hexagonal morphologies, with a particle size range of 50-70 nm, have been synthesized by a rapid microwave-assisted route in the solution state. The morphology of these materials is greatly tuned at low concentrations of the precursors used. The absorption band gaps (E-gap) are shifted to the visible region due to C loading, and the distorted spherical C-TiO2 exhibits a maximum energy shift relative to pure TiO2. Carbon gets deposited predominantly on the surface as graphitic carbon, in the preparative conditions, as confirmed by X-ray photoelectron, scanning electron microscopy elemental mapping and Raman spectroscopic studies. The rapid degradation of an endocrine disrupting agent and a persistent pollutant in wastewater, carbamazepine, by the rice grain shaped C-TiO2 is attributed to the large surface area (229 m(2)/g) of the particles and coexposure of the high surface energy and more reactive {001} facets along with the low energy and thermodynamically stable {101} facets.