Isotopic Exchange Between Hydrogen and Water Vapor over Supported Metal Catalysts. Part I. Kinetics of the Exchange

Abstract

Some rate data for the transfer of a deuterium atom tracer between hydrogen and water vapor, catalyzed by platinum supported on γ-alumina, are reported. Above 100 °C the transfer rate measured at 1 atm total pressure is shown to be free of mass transfer effects, and obeys an initial first order dependence on water vapor for vapor pressures less than 10 Torr. A near zero order dependence is observed at higher water vapor pressures. At temperatures below 100 °C the transfer rate is essentially independent of water vapor pressure between 5 and 100 Torr suggesting that surface adsorbed water is involved in the rate limiting transfer step.