Photoelectrodes for green hydrogen production : fabrication and assembly challenges

In the context of a transitioning energy landscape, the search for renewable and sustainable solutions to produce non-fossil energy carriers is intensifying. Green hydrogen, in particular, is positioned as a strategic option to meet the growing needs of hard-to-electrify sectors while limiting greenhouse gas emissions. However, its production remains constrained by high costs. Photoelectrochemical devices represent a relevant alternative for direct, autonomous solar hydrogen production. Nevertheless, these systems face several technological challenges related to light absorption and conversion, charge transfer at interfaces and electrochemical reactions at the electrode/electrolyte interface. This doctoral work, conducted within the framework of the PROSPER-H2 industrial chair (a collaboration between ENGIE and CEA), aims to overcome some of these challenges by developing photoelectrodes based on abundant materials, using simple, scalable, and industry-compatible processes. The ultimate goal is to design a tandem PEC-PEC system operating without external biais, capable of achieving a current density of 5 mA/cm² for a solar-to-hydrogen efficiency of 5% on an active area of 0,1 m². This work thus presents a comprehensive approach, from material design to interface optimization, toward an autonomous, stable, and high-performance tandem device.