Rutile TiO2 films with 100% exposed pyramid-shaped (111) surface: photoelectron transport properties under UV and visible light irradiation
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In this work, a facile hydrothermal method was employed to directly grow the rutile TiO2 film with 100% exposed pyramid-shaped (111) surface onto a FTO conducting substrate, and the resulting rutile TiO2 film was used as the photoanode after annealing at 450 C for 2 h in argon (Ar) to investigate photoelectrocatalytic properties under UV and visible light irradiation. The photoelectrocatalytic activities of the resultant photoanode under UV (main wavelength of 365 nm) and visible light (l > 400nm) irradiation were evaluated using water as the probe compound. The photoelectrocatalytic activity of the UV light illuminated photoanode was found to be 0.144 mA mW 1, significantly higher than that obtained from the visible light illuminated photoanode (0.102 mA mW 1). Despite this, the determined value of 0.102 mA mW 1 represents an excellent visible light photoelectrocatalytic activity of the photoanode. The origin of visible light activity could be attributed to the doped Ti3+ in the bulk TiO2. The superior photoelectrocatalytic activity could be due to the high reactivity of the exposed highenergy (111) surface and the superior photoelectron transport property. A photoelectrocatalytic method was used to manifest the photoelectron transport properties inside the rutile TiO2 film and concurrently quantify the inherent resistances (R0) of UV and visible light illuminated photoanodes. The determined R0 values were 93.5 and 91.3 U for UV and visible light illuminated photoanodes, respectively. The similar R0 values imply a similar photoelectron transport resistance inside the rutile TiO2 film under UV and visible light irradiation, confirming that the measured R0 is an inherent property of the photocatalyst film. This also implies that the rate of charge recombination is similar under UV and visible light irradiation. To our knowledge, this is the first time the electron transport properties of a rutile TiO2 photoanode have been concurrently investigated under UV and visible light irradiation.
Journal of Materials Chemistry A
Copyright 2013 Royal Society of Chemistry. This is the author-manuscript version of this paper. Reproduced in accordance with the copyright policy of the publisher. Please refer to the journal website for access to the definitive, published version.
Technology not elsewhere classified
Nanofabrication, Growth and Self Assembly