Effect of deposition of Ag nanoparticles on photoelectrocatalytic activity of vertically aligned TiO2 nanotubes

• Published in: Catalysis today Vol. 189; no. 1; pp. 93 - 100
• Main Authors: Gross, P.A., Pronkin, S.N., Cottineau, T., Keller, N., Keller, V., Savinova, E.R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 30-07-2012; Elsevier
• Subjects: Ag photodeposition; Catalysis; catalytic activity; Chemical Sciences; Chemistry; Colloidal state and disperse state; electrolytes; Exact sciences and technology; General and physical chemistry; lighting; nanoparticles; nanosilver; nanotubes; Photoelectrochemical cell; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Titania nanotubes; Photoelectrochemical cell; Ag photodeposition; Titania nanotubes; Water; Photoelectrochemistry; Scanning electron microscopy; Binary compound; Nanoparticle; Transition element compounds; Nanotube; Agglomeration; Decomposition; X ray; Precursor; Substrate; Heterogeneous catalysis; Impregnation; Electrolyte; Photoelectron spectrometry; Photoelectrocatalysis; Titanium oxide; Deposition
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2012.03.054

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► Ag nanoparticles were deposited on aligned TiO2 nanotubes by photodeposition. ► Activity of TiO2 nanotubes in water photodecomposition is effected by deposition of Ag nanoparticles. ► Increase of activity is tentatively explained by improved light absorption, especially in visible range. ► Decrease of activity is related to oxygen electrocatalytic reduction on Ag nanoparticles.
Deposits of Ag nanoparticles on TiO2 nanotubes have been prepared by ex situ photochemical deposition after substrate impregnation in AgNO3 solution. SEM demonstrated that nanoparticles with average size 40±12nm are uniformly distributed over the substrate without agglomeration. XPS analysis indicated that concentration of precursor electrolyte allows to control the amount of deposited Ag.
For the first time the effect of Ag nanoparticles deposition on photoelectrochemical properties, namely on the photocurrent of water decomposition of TiO2 nanotubes was studied. Depending on the illumination (visible vs. UV–visible), the applied bias, and the amount of deposited Ag, the latter may lead either to an increase or a decrease of photocurrent. Possible origins of the positive and the negative effect of Ag deposition on the photoelectrochemical activity of TiO2 are discussed.