Investigazione della reazione di metanazione della CO2 su catalizzatori Ni-CeO2: un approccio combinato XAS-DRIFT-MS.

CO2 concentration levels in the atmosphere are steadily increasing, and the tremendous impact of this greenhouse gas on our climate must be mitigated. One possible approach lies in the so-called Carbon Capture Storage and Utilization (CCS&U) strategies, i.e. the use of CO2 as a chemical resource to produce useful commodity chemicals. In particular, this experimental activity focused on the investigation of CO2 methanation reaction, or Sabatier reaction (i.e. CO2 + 4 H2 ⟶ CH4 + 2 H2O), which is gaining increasing interest for synthetic natural gas production, hence having the potential to decrease our dependence from fossil fuels. The idea is to exploit the reaction in the framework of Power-to-Gas technology (P2G), using surplus electric power coming from renewable sources to produce H2 by water electrolysis. Despite the potential of CO2 methanation reaction, e.g. low-cost catalysts and low temperature and pressure operation conditions, catalysts with improved activity, selectivity and slow deactivation rates still need to be developed. In this context, the experimental activity carried out during this Master’s Thesis work regarded the in situ and operando investigation of CO2 methanation reaction over two different types of Ni-doped CeO2 catalysts, synthesized at the CNRS in Strasbourg, by means of a combined X-Rays Absorption spectroscopy (XAS) –Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFT)- Mass Spectrometry (MS) study. The strength of this approach relies in the simultaneous application of different techniques, allowing to infer synergistic structural, electronic and vibrational information on the catalyst’s behaviour under operating conditions. The whole experimental part of this work has been carried out at BM23 beamline of the European Synchrotron Radiation Facility (ESRF) in Grenoble.