A membrane-free approach to water electrolysis using earth-abundant catalysts developed by an international research team offers a cost-effective and scalable approach to hydrogen production.

While conventional alkaline electrolysis operates at low current density and low pressure and emerging proton exchange membrane systems require the use of scarce noble metal catalysts, the new electrolyzer The components of the membrane-free flow electrolyzer. Source: Ning Yan et al.splits water at high current density using widely available catalysts. A hydrogen-rich catholyte and an oxygen-rich anolyte flow through the system with two identical and separate compartments featuring a sandwich-like architecture. During operation, the anolyte and catholyte cycle back and forth, continuously reversing the functions of each compartment as hydrogen gas of over 99% purity is produced.

This cyclic operating regime exploits the characteristics of a bifunctionally active electrode catalyst based on iron/cobalt compounds with nitrogen doped carbon. Tests demonstrated efficient operation at the highest current density reached of 750 mA/cm² under the potential bias of 2.1 V and ambient conditions in both deionized and tap water electrolyte.

The membrane-free electrolyzer designed by researchers from University of Amsterdam, Wuhan University and Wuhan University of Technology is described in Nature Communications.