Operando observation of methane conversion reactions by soft X-ray near-ambient pressure photoelectron spectroscopy

Abstract

Methane conversion reactions on Pd single crystals were investigated by soft X-ray near-ambient pressure photoelectron spectroscopy. AP-XPS and mass spectroscopy measurements were performed simultaneously during linear heating and cooling processes of the Pd samples in the presence of oxygen and methane gases to reveal surface oxidation states and reactivity. The reactivity depends significantly on the oxidation state of the surface. This indicates that gas pressure and composition are key parameters affecting the reactivity.