ISSN 19950780, Nanotechnologies in Russia, 2012, Vol. 7, Nos. 9–10, pp. 482–485. © Pleiades Publishing, Ltd., 2012. Original Russian Text © F.F. Orudzhev, F.G. Gasanova, Z.M. Aliev, A.B. Isaev, 2012, published in Rossiiskie Nanotekhnologii, 2012, Vol. 7, Nos. 9–10. 482 INTRODUCTION Phenol and its compounds are widely used in industry, but they are one of the most widespread con taminants of water objects. They can stay in the envi ronment for a long time owing to their stability and biological accumulation. In addition, they have highly toxic carcinogenic properties that cause significant damage to the environment and pose a threat to human health and aquatic ecosystems. Among the currently available methods of purify ing natural and waste waters from phenol, the most common are adsorption by activated carbon, chemical oxidation, biological treatment, etc., each of which have their limitations and drawbacks [1]. The use of photocatalysis for water purification from phenol is an alternative to existing methods and is a rapidly developing field of research in recent years [2–4]. One special case of the photocatalytic reactions are the photoelectrocatalitic reactions that occur at the interface between two conducting phases with electronic and ionic conductivity. Similarly to electro chemical reactions, they are accompanied by an elec tric current passing in the system [5]. The photoelectrocatalitic decomposition of organic compounds using semiconductors as catalysts has been used successfully in the decontamination of pol luted water and air flows. Among the semiconductors investigated as photocatalysts in this process, TiO 2 stands out due to its high sensitivity, absence of toxic ity, chemical stability, and commercial availability. However, due to a rapid recombination between the photogenerated electrons and holes in photocatalysis, the efficiency of the process may be low and the prac tical implementation is very difficult. In this case, the irradiation of TiO 2 with daylight does not lead to its excitation, since titanium dioxide is a wide band gap semiconductor and absorbs light only in the UV range of the spectrum. Doping TiO 2 with noble metals is one way to enhance its photocatalytic activity and enhance the absorption spectrum of sunlight. In [6–10], the authors reported on a significant improvement of the photocatalytic activity in TiO 2 when the surface is modified using Pt, Au, and Pd metals. An increase in the quantity of dissolved oxygen in the system leads to an increase in the rate as well as the photochemical and photocatalytic oxidation reactions of phenol and other organic compounds [11, 12]. In this paper we studied the photoelectrocatalitic oxidation of phenol on the platinumdoped titanium dioxide nanotubes under the pressure of oxygen [11, 12]. DESCRIPTION OF THE EXPERIMENT The photoelectrocatalitic oxidation of phenol was carried out in the following way. The phenol solution was flooded into the fluoroplastic unit with a volume of 200 ml (see [13] for more detail) and exposed to irradiation by natural or UV light, depending on the photoanode used. We used electrodes made of tita nium dioxide and platinummodified titanium diox ide as photoanodes, while the cathode was made of platinum foil. We used a mercury lamp as a source of UV light; the source of natural light was a fluorescent lamp. After the treatment of the solution within a certain time, we selected and filtered the probe and determined the concentration of phenol using a chromatograph (SE Instruments, Italy). To prepare a TiO 2 nanotube, a titanium plate was first mechanically cleaned and then subjected to chemical polishing in a solution of HF/HNO 3 /H 2 O (1: 4 : 5) for three minutes. Treated in this way, a tita nium plate with a surface area of 10.5 cm 2 was sub jected to electrolysis in the electrolyte solution of H 3 PO 4 (0.3 M) + HF (0.1 M) at a voltage of 30 V for Photoelectrocatalytic Oxidation of Phenol on PlatinumModified TiO 2 Nanotubes F. F. Orudzhev, F. G. Gasanova, Z. M. Aliev, and A. B. Isaev Dagestan State University, ul. Gadzhieva 43a, Makhachkala, 367001 Russia email: faridstkha@mail.ru Received May 4, 2012; accepted May 16, 2012 Abstract—The influence of oxygen pressure on the photoelectrocatalytic oxidation of phenol on TiO 2 /Ti and PtTiO 2 /Ti photoelectrodes under UV and visible light irradiation is investigated. It is shown that, as the oxy gen pressure increases from 0.1 to 0.7 MPa, the rate of the process rises about 1.1 times. DOI: 10.1134/S1995078012050102