Green hydrogen production has gained increasing attention in the past decade as the energy sector started to transition towards renewable energy sources and accelerated decarbonisation. As part of the X-Seed project, the principles of water electrolysis for hydrogen production were applied to develop a novel membrane-less electrolyzer operating under supercritical water conditions (above 374°C and 220 bar). Novel catalysts were synthesised as the first generation of electrodes tailored for supercritical water electrolysis.

Three perovskite-based nanofiber materials (SFM, PBCCF and LBCN) were synthesised using the electrospinning technique. Starting from polymeric precursor solutions, the materials were electrospun under optimized flow rates and voltages. A thermal treatment followed to remove the polymer and promote crystallization of the perovskite phase. The materials were characterized using XRD, ICP-MS, BET, and HR-SEM to evaluate their structural, compositional, and morphological features. Electrochemical characterization has been assessed first at normal temperature and pressure using HER and OER polarization curves up to 10 kA·m^-2. SFM exhibited the lowest HER overpotential (424 mV at 100 A·m⁻²) while PBCCF achieved an OER overpotential (443 mV at 10 mA·cm^-2) in 1M KOH. These results are promising for the application of perovskite-based nanofiber catalysts onto the selected electrode substrate for efficient hydrogen production under supercritical water conditions.

Acnowledgements

Project X-SEED with Grant Agreement number 101137701. The project is supported by the Clean Hydrogen Partnership and its members. Co-funded by the European Union. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the Clean Hydrogen Partnership. Neither the European Union nor the granting authority can be held responsible for them.

Reference: X-SEED Project - Supercritical Hydrogen