title: Synthesis and structure of nanocrystalline TiO2 with lower band gap showing high photocatalytic activity.
abstract: Nanocrystalline TiO2 was synthesized by the solution combustion method using titanyl nitrate and various fuels such as glycine, hexamethylenetetramine, and oxalyldihydrazide. These catalysts are active under visible light, have optical absorption wavelengths below 600 nm, and show superior photocatalytic activity for the degradation of methylene blue and phenol under UV and solar conditions compared to commercial TiO2, Degussa P-25. The higher photocatalytic activity is attributed to the structure of the catalyst. Various studies such as X-ray diffraction, Raman spectroscopy, Brunauer-Emmett-Teller surface area, thermogravimetric-differential thermal analysis, FT-IR spectroscopy, NMR, UV-vis spectroscopy, and surface acidity measurements were conducted. It was concluded that the primary factor for the enhanced activity of combustion-synthesized catalyst is a larger amount of surface hydroxyl groups and a lowered band gap. The lower band gap can be attributed to the carbon inclusion into the TiO2 giving TiO(2-2x)C(x) VO2**.
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012, India.
authors.forename: K
authors.initials: K
authors.lastname: Nagaveni
authors.forename: M S
authors.initials: MS
authors.lastname: Hegde
authors.forename: N
authors.initials: N
authors.lastname: Ravishankar
authors.forename: G N
authors.initials: GN
authors.lastname: Subbanna
authors.forename: Giridhar
authors.initials: G
authors.lastname: Madras
mesh_terms: D002384:Catalysis; D003460:Crystallization; D009682:Magnetic Resonance Spectroscopy; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry*; D010777:Photochemistry; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013818:Thermogravimetry; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: C009495:titanium dioxide; D014025:Titanium