Ozone-induced lean methane oxidation over cobalt ion-exchanged BEA catalyst under dry reaction conditions

Abstract

As the ‘Global Methane Pledge’ was launched at the UN COP26 climate conference in Glasgow, there is a growing need to develop efficient methods to remove lean methane emission or methane slip at low temperatures. In order to enhance the lean methane oxidation at temperatures lower than 200 °C, it can be effective to use ozone as an oxidant while applying an appropriate catalyst. In this study, we examined the activity of cobalt ion-exchanged BEA catalyst for ozone-induced lean methane oxidation under dry reaction conditions. The cobalt ion-exchanged BEA catalyst was more active than palladium and iron ion-exchanged BEA catalysts. It could initiate methane oxidation at ∼40 °C and reaches the highest methane conversion of 98% at 125 °C, maintaining the conversion higher than 50% in the temperatures from 55 to 185 °C. The most active cobalt species was the isolated mononuclear cobalt ions coordinated to BEA framework. Finally, we proposed the reaction mechanism based on the intermediate species identified by the Fourier transform infrared spectroscopy.