Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-IV-34W 0, μmol O 2/min0,25 1. 1%Pt/Degussa P 25 (SCR)2. pure Degussa P250,203. R20,154. 1% Pt/Hombifine N (SCR)0,105. pure Hombifine N6. R10,050,001 2 3 4 5 6Fig. 1. The initial rate of oxygen production over different catalysts.One can see that the best catalyst is rutile synthesized by TTIP hydrolysis in hydrochloricacid solution. This catalyst consists of rutile, which is the best phase of TiO 2 forphotocatalytic oxygen production [2], and has quite high surface area (~100 m 2 /g) due to lowtemperature of calcination. Pure and platinized Degussa P25, which consists of two phases –anatase and rutile – show a very high activity, too. The activity of pure rutile R1 is very lowlikely due to the very low specific surface area (~5 m 2 /g). Small amount of hydrogen wasdetected in the case of platinized specimens. So rutile (R2) and pure Degussa P25 are the bestphotocatalysts for individual oxygen production.Hydrogen can evolve only on platinized titania [3] so only platinized Degussa P25 andHombifine N were used for photocatalytic hydrogen production. The hydrogen emission rateon 1%Pt/P25 (SCR) was 0,01 μmol/min. It exceeds that in the case of 1%Pt/Hombifinene Nby a factor of three. The rate of hydrogen evolution for 1%Pt/P25 (PD) is lower than for1%Pt/P25 (SCR) and it is equal to 0,0081 μmol/min, despite many researchers in the fieldsuppose that the photodeposition (PD) of platinum is preferred. Thus, using self synthesizedrutile and platinized commercial Degussa P25 we can produce oxygen and hydrogen fromwater solution of ceric and cerious salts, respectively. Combining two photocatalytic reactorsand enter changing the reaction solutions of Ce 3+ to Ce 4+ we manage to obtain a cycle forphotocatalytic water splitting.AcknowledgementsThe authors want to acknowledge NATO grant SfP-981461 and ISTC grant 3305.References1. G. R. Bamwenda, H. Arakawa, Solar Energy Materials & Solar Cells, 70, 1-14 (2001).2. M. Ni, M. K. H. Leung, D. Y. C. Leung, K. Sumathy, Renewable and Sustainable Energy Reviews, 11, 401-425 (2007).3. S. Sato, Journal of Physical Chemistry, 69, 3531-3537 (1981).456