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

• Published in: Applied catalysis. B, Environmental Vol. 142-143; pp. 718 - 728
• Main Authors: Sridharan, Kishore, Jang, Eunyong, Park, Tae Joo
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01-10-2013; Elsevier
• Subjects: Catalysis; Chemistry; Cr(VI) reduction; Exact sciences and technology; General and physical chemistry; Graphitic carbon nitride; Methylene Blue; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; TiO2; Visible light active photocatalyst; Methylene Blue; Cr(VI) reduction; Visible light active photocatalyst; Graphitic carbon nitride; TiO2; Binary compound; Growth; Photocatalysis; Transition element compounds; Photocatalyst; Composite material; Methylene blue; Chemical reduction; Heterogeneous catalysis; Pollutant; Synthesis; Carbon nitrides; TiO; Titanium oxide; Environmental protection
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2013.05.077

•Co-doped TiO2 (TGU) microspherical nanorods are hydrothermally synthesized.•Thermal treatment of TGU at 300°C results in synergistic formation of graphitic C3N4–TiO2 composite.•Synergy formed by better linkage of TiO2 with g-C3N4, facilitates fast electron transfer.•Improved efficiency in the photodegradation of MB and reduction of Cr(VI) ions under visible light.
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°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.