OP-II-3

PP-III-25CO REMOVAL AT THE MICROSCALE:A 1-CENT GOLD PROX REACTORJiménez N. 1 , López E. 1 , Trifonov T. 2 , Rodríguez A. 2 , González de Rivera F. 3 ,Rodríguez L.I. 3 , Seco M. 3 , Rossell O. 3 , Llorca J. 11 Institut de Tècniques Energètiques, Universitat Politècnica de CatalunyaAv. Diagonal 647, Ed. ETSEIB, 08028 Barcelona, SPAINFax: (0034)934017149, E-mail: jordi.llorca@upc.edu2 Departament d’Enginyeria Electrònica, Universitat Politècnica de Catalunya3 Departament de Química Inorgànica, Universitat de BarcelonaIntroductionThe growing implementation of fuel cells for new portable electronic devices hasmoved research into improving reformers for in-situ hydrogen production, separationand purification. It is well-known that Pt-based anodes of fuel cells are easilypoisoned by CO. In this context, CO preferential oxidation (COPROX) is thepreferred final step to purify hydrogen streams from small-scale reformers [1].In recently pioneering publications we reported an innovative miniaturization forhydrogen production based on silicon micromonoliths [2,3]. This novel substratecontains millions of regular and parallel circular microchannels per square centimeterwhich results in a specific contact area ca. 100-fold larger than that of conventionalmicroreactors. These features solve the problem of moving down the scale and, atthe same time, increasing the reaction area available. Moreover, high heat transferrates are achieved due to the good thermal conductivity of silicon. In this work wereport a silicon micromonolith loaded with Au/TiO 2 catalyst for low-temperatureCOPROX aimed at downstream hydrogen purification for PEMFC feeding.Functionalization of silicon micromonolithsSilicon micromonoliths (13 mm in diameter, 0.2 mm height, see figure 1) wereprepared by photoassisted electrochemical etching which led to a substrate with >10 6straight and parallel circular channels of 3.3 micrometers in diameter. Themicromonoliths were thermally oxidized to form a thin SiO 2 layer on the channelwalls. A titanium dioxide layer was then deposited by decomposition of an alkoxideprecursor. Given the well-known ability of gold nanoparticles deposited on oxidesupports, such as TiO 2 , to selectively oxidize CO in H 2 -rich environments [4], Aunanoparticles capped with dendrimer were anchored on TiO 2 . The catalyst and the485