Document Type

Article

Rights

This item is available under a Creative Commons License for non-commercial use only

Disciplines

1.4 CHEMICAL SCIENCES, Inorganic and nuclear chemistry, Physical chemistry

Publication Details

Chemistry of Materials, Vol. 22, 2010, pp.3843–3853

Abstract

Nitrogen doped anatase-rutile heterojunctions are successfully synthesized through an ethylene-diaminetetraacetic acid (EDTA) modified sol-gel process.An FT-IR study of EDTA modified TiO2 gel confirms the existence of an ionic intermediate (as indicated by a Δν value of 233 cm-1).Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Raman spectroscopy are employed to study the phase evolution, phase purity, and crystallite size of samples. Formations of O-Ti-N and N-Ti-N bonds in calcined samples are confirmed using XPS and FT-IR spectro- scopy. AllEDTAmodified samples show significantly higher visible light photocatalytic activity than the unmodified sample. The most active nitrogen doped heterojunction obtained at 400C exhibits 9-fold visible light activity in comparison to the standard photocatalyst Degussa P-25. It is proposed that the photo excited electrons (from the visible midgap level) are effectively transferred from the conduction band of anatase to that of rutile causing effective electron-hole separation, which is responsible for the higher visible light activity and lower photoluminescence (PL) intensity

DOI

10.1021/cm903260f

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