Noble metal catalysts for methane removal

Using a bench-scale rig, the activities of Pt, Pd and Pt + Pd catalysts supported on gamma-Al2O3 and on TiO2 (anatase) for the complete oxidation of methane (300 ppmv) in air have been measured as a function of temperature; values of T-10, T-50 and T-90 together with the Arrhenius parameters (activation energy and pre-exponential factor) are reported. Pt is less active than Pd when deposited on the surface of the TiO2, but more active when deposited on gamma-Al2O3, however when combined, the Pt + Pd mixture is more active than either metal individually. The T-10 for Pt + Pd/gamma-Al2O3 was being as low as 228 degreesC. The significance of the Arrhenius parameters, for metal containing catalysts is that they exhibit compensation with increasing activation energy, while securing a more rapid increase in conversion from 0% to 100% when the temperature is increased. (C) 2003 Elsevier Science Ltd. All rights reserved.