Nitrogen-sensitized dual phase titanate/titania for visible-light driven phenol degradation
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)
- Institute of Chemical and Engineering Sciences 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore)
- Chemical Engineering Program, Masdar Institute of Science and Technology, PO Box 54224, Abu Dhabi (United Arab Emirates)
- Photocatalyse et Environnement, CNRS/Ecole Centrale de Lyon (STMS), 69134 Ecully Cedex (France)
A dual-phase material (DP-160) comprising hydrated titanate (H{sub 2}Ti{sub 3}O{sub 7}{center_dot}xH{sub 2}O) and anatase (TiO{sub 2}) was synthesized in a low-temperature one-pot process in the presence of triethylamine (TEA) as the N-source. The unique structure exhibits strong visible light absorption. The chromophore is linked to Ti-N bonds derived from both surface sensitization and sub-surface (bulk) doping. From transmission electron microscope (TEM) and textural studies by N{sub 2} physisorption, the composite exists as mesoporous particles with a grain size of {approx}20 nm and mean pore diameter of 3.5 nm, responsible for the high surface area ({approx}180 m{sup 2}/g). DP-160 demonstrated photocatalytic activity in the degradation of phenol under visible light ({lambda}>420 nm). The activity of the composite was further enhanced by a small addition (0.001 M) of H{sub 2}O{sub 2}, which also gave rise to some visible light activity in the control samples. This effect is believed to be associated with the surface peroxo-titanate complex. GC-MS analyses showed that the intermediate products of phenol degradation induced by visible light irradiation of DP-160 did not differ from those obtained by UV (band-gap) irradiation of TiO{sub 2}. The overall performance of the composite is attributed to efficient excitation via inter-band states (due to N-doping), surface sensitization, improved adsorptive properties of aromatic compounds due to the N-carbonaceous overlayer, and the presence of heterojunctions that are known to promote directional charge transfer in other mixed-phase titanias like Degussa P25. - graphical abstract: Nitrogen-sensitized dual phase titanate/titania photocatalyst showing extended visible light absorption and efficient photocatalytic degradation of phenol. Highlights: Black-Right-Pointing-Pointer Low temperature one-pot synthesis of visible light active dual phase photocatalyst. Black-Right-Pointing-Pointer The dual phase consists of nanoscale titanate and anatase titania phases. Black-Right-Pointing-Pointer The photocatalyst displays high activity in degrading phenol under visible light. Black-Right-Pointing-Pointer Mechanisms for the sensitization to visible light are considered.
- OSTI ID:
- 22149977
- Journal Information:
- Journal of Solid State Chemistry, Vol. 196; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
CONTROL
GAS CHROMATOGRAPHY
GRAIN SIZE
HYDROGEN PEROXIDE
IRRADIATION
MASS SPECTROSCOPY
NANOSTRUCTURES
NITROGEN
PHENOL
PHOTOCATALYSIS
SORPTIVE PROPERTIES
SURFACE AREA
SURFACES
SYNTHESIS
TITANATES
TITANIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY
VISIBLE RADIATION