Hydrogen production by electrolysis is the only process that enables hydrogen to be produced without carbon by-products. Electrolysis using anionic membranes is attracting increasing attention, as this technology makes it possible to consider electrodes without noble metals and non-fluorinated membranes.
At the anode, the kinetics of the OER reaction are the most limiting. It occurs under highly basic, high-potential conditions. Carbon is therefore not recommended as a support, as it is susceptible to oxidative degradation at the high potentials applied to the anode, or to nucleophilic OH ions in alkaline media.
The synthesis of non-noble catalysts on conductive supports such as fibers or foams would increase the electrical conductivity of the catalyst as well as the anchoring of the active site in order to increase the electronic active site/support interaction and the durability of the electrode.
On the cathode side, although HER catalysis is faster than that of OER, it remains a major obstacle to electrolysis reactions in alkaline media. Indeed, the overpotential of non-noble materials is on average 100 mV higher than that of platinum. However, our experience suggests that molybdenum-based catalysts hold great promise for the development of PGM-free catalysts. In order to optimize these catalysts, we plan to improve electrical conductivity by using carbonaceous supports and to work on the shape structure of these catalysts to improve HER kinetics.
The aim of this project is to provide the scientific community with new knowledge on materials that could be as efficient as the noble catalysts usually used in anionic electrolysis. The use of manufacturing and shaping processes proven in the field of PEM fuel cells offers a good chance of success. Another major contribution to AEM electrolysis will be the exploration of electrode material degradation mechanisms, about which very little is known at present.