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

PP-IV-34PHOTOCATALYTIC WATER SPLITTING WITH HYDROGENEVOLUTION IN Ce 3+ /Ce 4+ SYSTEMSEkaterina Kozlova a,b , Aleksander Vorontsov a,b , Tatayna Korobkina a,ba Boreskov Institute of Catalysis SB RAS, Novosibirsk, 630090, Novosibirsk, Russia,tel/fax: +7-383-333-16-17, e-mail: kozlova@catalysis.nsk.sub Novosibirsk State University , Novosibirsk, 630090, RussiaHydrogen as environmental friendly and high-energy fuel has attracted attention all overthe world for the last decade. Photocatalytic emission of hydrogen from water solution oforganic compounds is a very promising and interesting method of hydrogen obtaining.Quantum efficiency of hydrogen emission per one electron can exceed 10% overphotocatalyst platinized titania. Unfortunately we can produce only mixture of hydrogen andcarbon dioxide using organic donors. It is more profitable for pure hydrogen production to useinorganic donors, for example Ce 3+ ions. The use of the two-step photocatalytic andphotochemical splitting of water to oxygen and hydrogen using semiconducting metal oxidesand system Ce 3+ /Ce 4+ is considered imperative because of its promising application in solarenergy conversion systems [1]. In our work, we used solution of Ce 2 (SO 4 ) 3 for hydrogenproduction and solution of Ce(SO 4 ) 2 for photocatalytic oxygen production. Bare andplatinized titania was used as a photocatalyst.Photocatalytic hydrogen and oxygen emission from Ce 2 (SO 4 ) 3 and Ce(SO 4 ) 2 solution wascarried out by the following method. Water suspension with catalyst and the initial compoundwas placed in a sealed thermostated reactor under argon atmosphere and illuminated by a1000-W high-pressure mercury lamp under continuous stirring. The concentration ofCe 2 (SO 4 ) 3 or Ce(SO 4 ) 2 was varied from 1 to 2 mM, catalyst concentration was 0.75 g/L,temperature 20 °C. Concentration of hydrogen and oxygen was measured by means of a gaschromatograph LChM-8, that of Ce 3+ and Ce 4+ by means of Lambda 35 Perkin-ElmerUV/Vis-spectrometer. Bare and platinized commercial TiO 2 Degussa P25 and Hombifine N,and self-synthesized rutile were used as catalysts. Ruthile was synthesized by Degussa P25calcination at 950 °C (R1) and by hydrolysis of titanium tetraisopropoxide (TTIP) in 1M HClsolution with calcination at 350 °C (R2). Noble metals were deposited by soft chemicalreduction (SCR) and photodeposition (PD) techniques.We have carried out experiments for oxygen production from water solution of Ce(SO 4 ) 2 .Fig. 1 shows the initial rate of oxygen production for six catalysts.455