Role of surface/interfacial Cu2+ sites in the photocatalytic activity of coupled CuO-TiO2 nanocomposites

Gonghu Li, Nada M. Dimitrijevic, Le Chen, Tijana Rajh, Kimberly A. Gray

Research output: Contribution to journalArticlepeer-review

287 Scopus citations

Abstract

Coupled CuO-TiO2 nanocomposite photocatalysts were prepared by a deposition precipitation method and were characterized with a variety of techniques. Electron paramagnetic resonance (EPR) spectroscopy was employed to study the local structures of surface/interfacial Cu2+ sites using Cu2+ as a sensitive paramagnetic probe. The addition of bulk CuO to TiO2 led to decreased photocatalytic efficiency in the degradation of methylene blue. However, doping with a very small amount of CuO (0.1 wt % copper loading) significantly enhanced the photocatalytic activity of TiO 2. EPR study of the TiO2 surface revealed the presence of both highly dispersed CuO clusters and substitutional Cu2+ sites (Ti-O-Cu linkages) at 0.1 wt % copper loading. The data suggest that the Ti-O-Cu linkages contributed to the improved photooxidative activity of the 0.1% CuO-TiO2 nanocomposite. In contrast, at higher loadings the bulk form of CuO created charge recombination centers lowering the photoactivity of the composites.

Original languageEnglish (US)
Pages (from-to)19040-19044
Number of pages5
JournalJournal of Physical Chemistry C
Volume112
Issue number48
DOIs
StatePublished - Dec 4 2008
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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