Thermocatalysis for green hydrogen production: tuning oxygen exchange capability in perovskites

In the transition to a greener economy, new energy carriers are needed, with the objective of delivering renewable energies to every use and device. Hydrogen can be suitable for many of the applications (it can be converted to electricity in fuel cells, stored in adequate vessels, consumed in industrial chemical reactions), but most hydrogen available nowadays comes from fossil sources through reforming (the so-called “grey” hydrogen). Instead, “green” hydrogen should come from water, through processes of electro-, photo- or thermolysis. The objective of this thesis is to find suitable catalysts for thermolysis of water, thought to be used in solar concentrators at low temperature (<1000°C). For these requirements, perovskite oxides will be adopted: the starting point is an oxide of Lanthanum, Strontium and Cobalt. The goal is to maintain oxygen exchange properties (in terms of oxygen thermally released and re-obtained, maintaining structural stability) with partial substitution of Co(III) ions with other elements, as Cobalt is a Critical Raw Material, besides posing health (and economical) issues. Iron and Manganese are the favoured candidates because of the similar ionic radius (about 70 pm) and the great number of oxidation states available. The obtained materials will be analysed through XRD, XPS, SEM, EDX and BET. For catalytic properties, TPR (Temperature Programmed Reduction) and TPD (Temperature Programmed Desorption) measures will be conducted.