A catalytic differential reactor was developed and constructed which enables both a differential and an integral evaluation of catalyst systems. The above-mentioned reactor is an adiabatically operated, ideal tubular flow reactor with five catalyst stages connected in series. A literature search has shown that potentially suitable catalysts can be assigned to the substance classes of noble metals, metal oxides, perovskites, zeolites as well as mixtures of noble metals and metal oxids. With the aid of catalyst screening, four potential catalysts were chosen from the catalysts of the above substance classes and subjected to a thorough investigation methodology. The catalysts concerned are Pt on [gamma]-Al₂O₃, Pt on zeolite, La₂O₃/Cr₂O₃/Pt and [Sr_0.4La_0.6][Co_0.9Pt_0.1]O₃. The activity and selectivity of these four catalysts with respect to methanol/hydrogen conversion are investigated in the kinetically controlled range. Empirically determined power laws are established and conclusions drawn concerning physical reaction mechanisms. During catalytic combustion, a real anode exhaust gas mixture is converted at the four catalysts in order to test their suitability in the transition region and in the region controlled by mass transfer.

The result is that all four catalysts have the potential for a complete combustion of methanol, CH₃OH, and hydrogen, H₂, without major pollution. As regards the noble metals, the mixed catalysts La₂O₃/Cr₂O₃/Pt and [Sr_0.4La_0.6][Co_0.9Pt_0.1]O₃ show the best conversion properties in comparison to the pure noble metals. The absolute and specific costs for the conversion of a defined fuel gas mass flow are clearly below the costs of the pure noble metals. The mixed catalysts, especially the perovskite [Sr_0.4La_0.6][Co_0.9Pt_0.1]O₃, are a more active and cheaper alternative to the well-known Pt on [gamma]-Al₂O₃. They are suited as oxidation catalysts in the catalytic burner of a fuel cell drive system.