III International Conference

PP-III-13VISIBLE LIGHT DRIVEN Pt/TiO 2 CATALYSTS FOR THE PHOTOCATALYTICDEGRADATION OF 4-CHLOROPHENOL IN AQUEOUS SOLUTIONKryukova G. 1 , Zenkovets G., Shutilov A., Guenther K. 2 , Fassler D. 2 , Wilde M. 1 , Richter K. 1Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia1 GNF eV, Volmerstrasse 7B, D-12489 Berlin-Adlershof, Germany3 GMBU eV, Felsbachstrasse 7, D-07745, Jena, GermanyE-mail: gnf-berlin@t-online.deThe photocatalytic degradation of 4-Сhlorophenol (4-CP) in water solution as a modelreaction was investigated on Pt/TiO 2 catalysts when illuminated with visible (λ of 450 nm)light. The catalyst under study with 1 % of Pt shows higher efficiency for thephotodegradation of 4-СP, comparing with that of Pt-modified P-25. The observedphotocatalytic behavior of Pt-supported catalysts were found to depend on their structuralarrangement.IntroductionTiO 2 is extensively used in the photocatalytic degradation of organic pollutants due to itshigh oxidative power, photostability, and nontoxicity [1]. However, severe limitation of thismaterial lies in the large band-gap (3.2 eV for bulk TiO 2 ) that drives the photosensitivity tothe UV region responsible for only 3% of the solar spectrum. According to published results,it is obvious that doping of TiO 2 with different elements extends light absorption into thevisible region [2]. Here the results of the photocatalytic testing of Pt/TiO 2 catalysts for thedegradation of 4- Chlorophenol (4-CP) in water upon irradiation with visible light as well asstructural peculiarities of the catalysts are described.ExperimentalPure TiO 2 and Pt/TiO 2 catalysts with 0.5-2 wt% Pt were synthesized according to [3].Sample of 1% Pt on P-25 (Degussa) was prepared through photoreduction of PtCl 4 solutionadded to the oxide support. Catalysts were studied with XRD, HRTEM, XPS. The activitieswere measured by the decomposition of 4-CP in concentration of 2 x10 -4 mol/L -1 in water at20 o C in the dark and after illumination for 2 hours with four Luxeon 3,4 W LED lamps(maximal 470 nm). Content of 4-CP in the reaction mixture before and after the run weredetermined from characteristic absorbance with on-line UV-Vis spectrometer.Results and discussionFig. 1 shows that dark adsorption of 4-CP on the synthesized Pt/TiO 2 catalysts does notpractically change with growth of Pt content and remains as low as 10 %. After illumination,the photodegradation of 4-CP increases from 38 up to 63 % for 0.5 and 1 % Pt, respectively,and quickly declines in the case of the sample with highest (2 %) concentration of thesupported metal. For pure P-25 (Degussa) removal efficiency is lower - photodegradation of4-СР does not rise over 13 %, whereas after its modification with 1 % Pt thephotodegradation grows but achieves only 40 %.492