III International Conference

PP-II-147CHARACTERISATION OF NEW GOLD CATALYSTS SUPPORTED ON MIXEDOXIDES FOR THE WATER GAS SHIFT AND PREFERENTIAL CO OXIDATIONREACTIONSVindigni F., Manzoli M., Chiorino A., Tabakova T. 1 , Boccuzzi F.Department of Chemistry I.F.M., Univrsity of Turin and NIS Centre of Excellence, Turin, Italy1 Institute of Catalysis, Bulgarian Academy of Science, Sofia, BulgariaE-mail: floriana.vindigni@unito.itHRTEM and FTIR characterisation on three new gold catalysts supported on mixedoxides for WGS and PROX reactions are here reported. Two of these are supported on mixedceria-titania oxides, whit different ceria loading (20 % and 50 %), the other is supported onmixed ceria-zirconia oxides. The catalytic data on WGS reaction show that the addition ofceria has a positive effect, on the activity of these new samples, probably due to the presenceof new gold species.1. IntroductionCatalytic systems containing highly dispersed gold have received great interest from bothexperimental and theoretical points of view. Due to their high catalytic activity, particularly inCO oxidation at low temperature (1, 2), they are regarded as promising candidates for H 2production, through methanol decomposition and water gas shift (WGS) reactions, andpurification, through preferential CO oxidation (PROX). The nature of the support on whichgold is dispersed plays a crucial role in determining the catalytic activity. In particular, theceria supported systems are very stable and exhibit a high activity for the WGS reaction (3)over a wide temperature range, at different space velocity and H 2 O/CO ratios (4).Our study, recently performed, on the two gold catalysts supported on mixed ceria-titaniaoxides, with different ceria loading (20 %, AuCe0.2Ti0.8, and 50 %, Au0.5Ti0.5), has shownthat the addition of ceria to titania has a beneficial effect on the stability and on the activity inWGS reaction (5). In order to get a quite deeper interpretation of the positive effect of ceria,TEM and FTIR characterisations have been undertaken on another new gold catalystssupported on mixed CeO 2 -ZrO 2 oxides (50 % ceria loading.). All the catalysts were preparedby deposition-precipitation method and subsequent calcination at 670 K, to generate strongcontact between the metal and the oxide support. The effect on the gold dispersion and on thecatalytic activity of different preparation of the supports before the deposition has also beeninvestigated.433