Selective carbon monoxide oxidation in the presence of hydrogen

Selective oxidation of CO in H2 is an important reaction for producing hydrogen from hydrocarbons suitable for use in fuel cells. Pt has been found to be an active catalyst for this reaction.{09}Metal foams as catalyst support structures offer excellent flow characteristics. The main objective of this study was to study the use of Pt and PtFe/alumina powder and washcoated metal foam catalysts for selective CO oxidation in the presence of H 2 using isotopic transient kinetic analysis (ITKA).; The activity results at 90°C and 1.8 atm showed initial rapid deactivation of both powdered Pt and PtFe catalysts to steady-state activity. PtFe catalyst was 4 times more active and 2 times more selective compared to the Pt one. Based on the ITKA results, initial partial deactivation for Pt was due primarily to a decrease in active intermediates; however, the initial rapid partial deactivation for PtFe was also the result of a decrease in the average intrinsic site activity. It would appear that carbon deposition causes the initial partial deactivation of Pt and may partially do so for PtFe. However, evidence suggests that reoxidation of Fe is likely a significant cause of the loss of activity of PtFe. For Pt/gamma-Al2O3, a significant increase in CO oxidation rate and the surface concentration of CO2 intermediates ( Ni-Co2 ) with an increase in temperature (80--110°C) or total pressure was observed (1.2--3 atm).; The study on the effects of using gamma-Al2O3-washcoated metal foams (FeCrAlY) as structural supports for Pt catalysts showed a significant impact of Fe impurities on the properties of the foam-based Pt catalysts. These Pt catalysts exhibited similar properties as what was observed for the Fe-promoted Pt powdered catalyst. Foam-based PtFe catalysts exhibited reaction properties similar to those of the powdered PtFe/gamma-Al2O 3, despite low chemisorption uptakes. These catalysts exhibited only a slight change with time-on-stream of CO oxidation rate and %CO2 selectivity and did not show the rapid initial deactivation, which make them excellent candidate for commercial use. The results indicate that Pt and PtFe catalysts for selective CO oxidation in H2 can be prepared successfully using washcoated metal foam support structures.