Fuel cells are electrochemical devices which convert chemical energy contained in the fuel into electrical energy, with high efficiency and low environmental impact. Solid Oxide Fuel Cells (SOFCs) are one of the FC systems, where the electrolyte is a solid oxide. This feature implies the requirement of high operating temperatures, and it is possible to distinguish SOFCs in two subcategories: intermediate (500-800°C) and high (800-100°C) temperature ones. Generally, SOFCs are characterized by the migration of oxygen ions through the electrolyte, which is possible due to the high temperature that enhances their diffusion. However, in recent years, another type of SOFC has been investigated: H-SOFC. The working principle behind H-SOFC is similar to the one of conventional O-SOFC, however the charge carriers in the electrolyte are not O^2- but rather protons, H⁺. Since protons are smaller, it is possible with H-SOFC to maintain good ionic conductivity at lower temperatures.
One of the main advantages of these devices is the big versatility of the fuels. The combination of high temperatures and the flexibility of the catalysts allow the use of both C-containing hydrocarbons (methane, ethane, methanol) and C-Free Fuels such as hydrogen and ammonia. Our work in this topic is focused on the development of specific catalysts for the operation in the Intermediate Temperature (IT) range, for both the anodic and the cathodic compartment.

Another aspect of our research is the development of similar devices, namely Solid Oxide Electrolysis Cells (SOECs), which allow to convert electrical energy into chemical one to provide it in the formation of a less thermodynamically stable molecule. The device for fuel production from electricity and electricity from fuel is essentially the same, i.e. a fuel cell that operates with a potential applied is the starting point for building an electrolyser.
SOECs work at lower temperatures (350-800°C) so the choice of the catalyst is crucial, since in our group we try to avoid scarce noble metals such as platinum. However, SOECs have shown to possess a major advantage: their energy-conversion efficiency can even overcome 100% in some operation mode due to the possibility to use heat from other processes as a source of energy.
One of the research topics is focused on the co-electrolysis of water and carbon dioxide, which allows to produce syngas (H₂ + CO). This could possibly be leading to a large-scale conversion of atmospheric CO₂ into a useful chemical using only water. Moreover, syngas produced by SOECs can be converted to hydrocarbons via a Fischer-Tropsch process. Hypothetically, using these devices, it could be possible to synthetize methane with completely sustainable processes by coupling a renewable energy source to a SOEC and a Fischer-Tropsch reactor.
The second aspect of our research involving SOECs is the synthesis of ammonia as fuel for energy storage. The Haber-Bosch process is the predominant route for nowadays ammonia synthesis, yet the electrochemical one benefits of zero emission of carbon dioxide starting from just nitrogen and water. The main challenge is this aspect is again finding a suitable electrode, since the Nitrogen Reduction Reaction (NRR) faces issues such as the N₂ high bonding energy, high ionization potential and ultralow solubility in water, which limit the reaction both thermodynamically and kinetically.
The last and final concept that makes Solid Oxide Cells interesting and worthy to be studied is the reversibility, which allows to switch the same device from electrolysis mode to the fuel cell mode just by tuning the open circuit potential (OCP). The whole device is commonly known as R-SOFC, reversible SOFC: investigating this field would allow both an easy storage of energy excess from renewable sources and an efficient re-conversion to electrical energy when needed. Moreover, SOECs would greatly benefit from the switching between the two modes, since it has proven to significantly reduce the long term degradation of the cell.