A parametric study of selective CO oxidation using particulate and monolithic Pt-Co-CeO2 catalysts

Abstract

The objective of this thesis was to conduct a parametric study of selective CO oxidation using particulate and monolithic Pt-Co-CeO2 catalyst supported on alumina. In this comparative study, the monolithic catalysts were prepared by applying a layer of alumina support on to the walls of a cordierite monolithic carrier by colloidal coating method, termed as wash-coating, and then impregnating active components. Colloidal alumina coated and 1.4%Pt-1.25%Co-1.25%Ce impregnated monolithic catalysts were tested for the preferential CO oxidation reaction in a micro-reactor flow system under a total flow of 100 cm3 min–1 using reaction temperatures in the 110-170°C range and typical feed compositions. The effect of calcination temperature, reaction temperature, Co content and residence time on catalyst activity and selectivity was investigated. The most suitable calcination temperature was found to be 700°C for monolithic catalysts which exhibited the highest catalytic activity towards CO oxidation approaching 100 per cent CO conversion at a temperature of 170°C in a feed containing 1.0 mol per cent CO, 1.0 mol per cent O2 and 60.0 mol per cent H2 with balance helium. The Pt and Co loadings on monolithic catalyts were determined by Inductively Coupled Plasma (ICP) analysis. In the light of ICP results indicating lower active component loadings on the cordierite structure, particulate 1.18%Pt-0.06%Co-1.25%Ce/γ-Al2O3 was prepared to match the monolithic catalyst composition and was tested for preferential CO oxidation in a microreactor flow system under a total flow of 100 cm3 min–1 using reaction temperatures in the 90-150°C range. 99.4% conversion was obtained over the particulate catalyst at 130°C in a feed containing 1.0 mol per cent CO, 1.0 mol per cent O2 and 60.0 mol per cent H2 with balance helium.