Novel visible light active graphitic C3N4-TiO2 composite photocatalyst: Synergistic synthesis, growth and photocatalytic treatment of hazardous pollutants

Novel visible light active graphitic carbon nitride TiO2 (g-C3N4-TiO2) composite photocatalyst is prepared through a thermal transformation methodology. C and N co-doped TiO2 (TGU) microspherical nanorods, were prepared initially by hydrothermal process, using urea and D-glucose as the dopant precursors. Pyrolysis of TGU at 300 degrees C in open air, transformed it to g-C3N4-TiO2 (TCN) composite. Structural and morphological characterization on TCN composites, using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM), reveals the growth of g-C3N4 (CN nanosheets) on doped TiO2. Plausible growth mechanism is predicted based on the morphological investigations. Band gap energy of the samples was estimated using UV-vis diffuse reflectance (DRS) spectroscopy and TCN composites were found to be active under visible light. Efficiency of the prepared samples were investigated by monitoring the degradation of Methylene Blue (MB) and by the reduction of Cr(VI) ions. Improved photocatalytic activity in TCN is observed owing to the formation of a synergistic heterojunction, which facilitates a fast electron transfer at the interface between CN and doped TiO2. Visible light absorption capability of both CN and doped TiO2, complements the synergy factor. This synergistic approach, could prove useful for the design and development of other visible light active photocatalysts with high chemical stability. (c) 2013 Elsevier B.V. All rights reserved.