Highly Visible Light Active TiO2−xNx Heterojunction Photocatalysts
Year: 2010
Type: article
Abstract: Nitrogen doped anatase-rutile heterojunctions are successfully synthesized through an ethylenediaminetetraacetic acid (EDTA) modified sol−gel process. An FT-IR study of EDTA modified TiO 2 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 spectroscopy. All EDTA modified samples show significantly higher visible light photocatalytic activity than the unmodified sample. The most active nitrogen doped heterojunction obtained at 400 °C 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.
Source: Chemistry of Materials
DOI: 10.1021/cm903260f
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1490542272