Effect of Pt particle size on H/D exchange of methane over alumina- and zeolite-supported catalysts

Abstract

Deuterium exchange in methane was studied over a series of Pt/Al₂O₃ and Pt/mazzite catalysts. The reaction proceeds by a simple stepwise mechanism with CH₃D being the primary product. Large and small metal particles located in zeolite and alumina catalysts have different catalytic activity with respect to deuterium exchange in methane. The rate of reaction per Pt atom was the same on the catalysts investigated for particles > 15–20 Å and considerably lower than the rate of reaction on samples with smaller Pt clusters. The activity of small clusters of Pt (diameter < 15–20 Å) depended on the nature of the support.