Oscillatory Behaviour During Ethane Oxidation Over Nickel and Cobalt Catalysts

Abstract

Oscillatory behaviour during ethane oxidation over a nickel foil and a cobalt foil has been studied using on-line mass-spectrometry and video recording of the catalyst surface colour. It was demonstrated that during the oscillatory behaviour, periodic transitions of the catalyst surface from an oxidised state to a reduced state occurred together with a variation of the catalyst temperature. Simultaneous measurements of gas phase concentrations revealed that mostly CO2 was produced over the oxidised state, while CO and H2 production rates reached their maxima over the completely reduced surface. The comparison of the observed oscillations with known oscillations during methane oxidation over nickel and cobalt foils has been done. It was shown that the higher reducing ability of ethane was the reason of an increase of the frequency of the oscillations over both catalysts and a significant decrease of the temperature range of the oscillations over the cobalt foil.