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Issue 35, 2017
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Engineering defects and photocatalytic activity of TiO2 nanoparticles by thermal treatments in NH3 and subsequent surface chemical etchings

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Abstract

TiO2 nanoparticles with N dopants were prepared by thermal treatments in NH3 and their surface defects were controlled by post chemical etching in HF to find out the influence of the N dopants on photoactivity. The effect of N-doping is found to enhance the photoactivity of TiO2, but is strongly dependent on the degree of N-doping and the detailed distribution of nitrogen species within the TiO2 nanoparticles. In particular, the N-rich layers formed near the surface are found to contribute to the enhanced photoactivity due to the reduced band gap. But, the increase in the N concentration may induce defects that act as recombination centers and reduce the photoactivity. Subsequent chemical etching in HF confirms the existence of the substitutional N species near the surface from the observation of paramagnetic N species. But, prolonged HF treatments are found to decrease the photoactivity primarily due to the removal of the N-rich surface layers that are responsible for the enhanced photoactivity. Our results show that the photoactivity of N-doped TiO2 is strongly influenced by the type and the density of the N dopants induced by the N doping.

Graphical abstract: Engineering defects and photocatalytic activity of TiO2 nanoparticles by thermal treatments in NH3 and subsequent surface chemical etchings

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Publication details

The article was received on 26 May 2017, accepted on 11 Aug 2017 and first published on 11 Aug 2017


Article type: Paper
DOI: 10.1039/C7CP03579A
Citation: Phys. Chem. Chem. Phys., 2017,19, 24049-24058
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    Engineering defects and photocatalytic activity of TiO2 nanoparticles by thermal treatments in NH3 and subsequent surface chemical etchings

    X. Yu, Y. Wang and Y. K. Kim, Phys. Chem. Chem. Phys., 2017, 19, 24049
    DOI: 10.1039/C7CP03579A

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