- The Sabatier reaction is a key process in the "power-to-gas" application which is considered to con-tribute to future chemical energy storage systems. In this
contribution we focus on the catalytic active sites of a NiO catalyst supported on SiO2(NiO/SiO2) which is commonly used in the Sabatier reaction. A novel technique for the characterization of the active sites is presented and dis-cussed using thermal desorption spectroscopy at ambient pressure. This analytical tool is operated under reaction conditions and allows element specific measurements during the catalytic process of CO2 reforming towards methane. Beside the desorption experiments, XPS and XAS measurements of pristine and catalytically used samples are performed to determine the influence of the Sabatier reaction conditions on the surface structure of the catalyst.