Abstract
Chemical treatment followed by thermal annealing of titanium dioxide nanoparticle film surfaces with urea or ammonium acetate were found to exert a profound influence on their photoelectrochemical or photocatalytic activity. These films were dip-coated over conducting substrates, then dipped in urea or ammonium acetate aqueo us solutions, and finally baked at 300 or 500°C to yield two sets of chemically-treated TiO2 (CT-TiO2) films. The incident photon to electron conversion efficiency (IPCE) of the CT-TiO2 films in the near-UV region was significantly higher compared to the pristine (untreated) TiO2 samples baked similarly at 300 or 500°C. Higher photocurrents for formate photo-oxidation were also observed for the CT-TiO2 samples relative to their untreated TiO2 counterparts. All the CT-TiO2 films showed better photocatalytic activity toward Cr(VI) reduction with respect to their untreated TiO2 counterparts. The enhanced performance of the CT-TiO2 films was attributed to morphological changes as seen in scanning electron microscopy images. Possible reasons for the performance improvement in terms of better charge carrier separation properties of the CT-TiO2 films are finally discussed.
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Cheng, S.T., Chenthamarakshan, C.R., de Tacconi, N.R. et al. Photo-electrochemical and photocatalytic properties of chemically-treated and thermally-annealed titanium dioxide films. Res. Chem. Intermed. 33, 225–237 (2007). https://doi.org/10.1163/156856707779238757
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DOI: https://doi.org/10.1163/156856707779238757