Oscillatory oxidation of H2 over a Pt catalyst

Oscillatory oxidation of hydrogen over a polycrystalline platinum wire has been systematically studied near atmospheric pressure in a clean flow reactor. Oscillations in the temperature of the catalyst and the composition of the exit gas stream were observed for inlet gas compositions, 1.5% ≤ PH2PO2 ≤ 15%, where PH2 and PO2 are the respective partial pressures of hydrogen and oxygen in the gas stream. The oscillations occurred for gas temperatures from 106 to 190 °C. Waveforms, which had up to several peaks per cycle, varied in shape from the relaxation type to nearly sinusoidal. Their behavior as a function of time, gas flow rate, and gas temperature is characterized for different ranges of PH2PO2. Changes in oscillatory behavior were seen after the catalyst was reetched.