Investigating the structure-activity correlation of Fe-based catalysts during H2 production via CH4 pyrolysis by combined operando PXRD and

Fe-based catalysts are active catalysts for the catalytic decomposition of methane, key-reaction for the energy transition, which leads to pure H2 and solid C. Despite the interest, a full comprehension of the structure-activity relationship for Fe-based catalysts is still under way. In our group we focused on experimental and modelling activity on CH4 pyrolysis over Fe/Al2O3 catalysts. To rationalize the results in terms of Fe active site/phase, with this proposal we aim at systematically investigate catalyst modifications during activation and pyrolysis reaction by operando powder X-ray diffraction combined with operando XAS on a series of samples, varying the Fe loading (12 - 100 wt% Fe, with Al2O3 as textural promoter). We will focus on high-quality PXRD and XAS data collection in reaction conditions, to determine the metal active phase structure and the role played by metastable and intermediate phases, as well as the changes in Fe oxidation state and average coordination numbers.