This Self-Renewing Electrode Could Make Green Hydrogen Cheaper to Produce

Researchers at the Chinese Academy of Sciences have developed a self-renewing electrode that could make green hydrogen production cheaper and longer-lasting, by turning a normally damaging process into a design feature.

Electrolysis splits water into hydrogen and oxygen using electricity. When that electricity comes from renewable sources such as solar or wind power, the hydrogen produced carries no direct carbon emissions. But the oxygen evolution reaction (OER), a key step in the process, moves far more slowly than hydrogen formation and requires highly active catalysts — catalysts that can dissolve, restructure or stop working under the intense conditions inside a working electrolyzer.

The team, led by Guowen Meng and Bin Chen at the Institute of Solid State Physics, part of the Hefei Institutes of Physical Science, created an electrode combining five metals — nickel, cobalt, iron, chromium and vanadium — in a single high-entropy antiperovskite structure. Rather than being applied as a separate coating, the material was grown directly onto porous nickel foam. The work was published in the journal ACS Nano.

In an alkaline electrolyte, the electrode needed only 279 millivolts of extra voltage to reach a current density of 100 milliamperes per square centimeter, and it kept working for more than 500 hours. Installed in an anion exchange membrane (AEM) electrolyzer, it delivered 500 milliamperes per square centimeter at a cell voltage of 1.662 volts and stayed stable for more than 400 hours with little loss of performance.

Analysis showed the electrode was not chemically static: some of its metal components gradually dissolved during use, letting a new active layer form at the surface that improved charge transfer and oxygen evolution rather than simply degrading the catalyst, Meng said.