Performances of Supported Noble Metal Catalysts and Kinetics over Pd/ZrO₂ for Methanol Decomposition

Abstract

Decomposition of methanol has been studied over various noble metal and copper catalysts at temperatures from 300 to 450°C. Screening experiments showed that Rh, Pd, and Pt catalysts supported on ZrO₂ had high activities and high selectivities for carbon monoxide and hydrogen. The Pd/ZrO₂ catalyst was not deactivated with time on line.
From a kinetic study, it was found that the partial pressure dependency of the initial reaction rate on the Pd/ZrO₂ catalyst was zero-th order with respect to methanol. This means that a methanol molecule is strongly adsorbed on the catalyst surface and the rate determining step involves the removal of hydrogen from an adsorbed methoxy group.
Further, the decomposition rate over the Pd/ZrO₂ catalyst was increased by hydrogen and decreased by carbon monoxide.