Surface Characteristics and Catalytic Oxidation of CO on Silicalites and Silicalites Containing Cobalt, Copper and Silver Oxides

Abstract

Two silicalite samples, S1 and S2, were prepared hydrothermally in the presence of tetrapropylammonium bromide (TPA-Br) and tetrabutylammonium bromide (TBA-Br), respectively. Cobalt oxide, copper oxide or silver oxide (all at 10 wt% concentration) were incorporated into the S1 and S2 silicalites by impregnation methods. The structural and textural properties of the prepared samples were studied using a variety of techniques together with their ability to catalyze the oxidation of CO. The results obtained indicated that S1 and S2 existed as pure phases with structures analogous to those of ZSM-5 and ZSM-11 zeolites, respectively.Electron microscopic analysis showed that the crystalline morphology of S1 and S2 consisted of intergrown discs and shelf-like shapes with diameters in the range 10-15 μm and 29-33 μm, respectively. Differences noted during kinetic studies of CO oxidation over the prepared samples were discussed.