Durability and lifetime in PEM electrolysis depend strongly on the choice of catalyst materials. Electrolyzers are expected to operate for more than ten years under demanding conditions, including high electrical potential, acidic environments, high temperature, and dynamic operation linked to renewable electricity sources. These conditions directly affect the key functional properties of a catalyst: catalytic activity, conductivity, and stability.

At the anode, the oxygen evolution reaction creates a highly aggressive environment. Pure oxygen, protons, and electrical potential accelerate chemical reactions and material degradation. These factors can reduce catalytic activity, disrupt conductivity, and lead to structural breakdown of the catalyst. To maintain performance over time, all three properties must be preserved simultaneously. This is why an iridium catalyst is indispensable. Iridium combines high catalytic activity with exceptional stability and maintains its functionality even under these harsh conditions.

At the cathode, the environment is less aggressive, but durability still depends on maintaining catalytic activity and conductivity in an acidic medium. A platinum catalyst provides this combination and ensures stable hydrogen generation over long operating periods.

Catalyst design also plays a major role in durability. Approaches such as supported iridium catalysts or mixed oxides that combine iridium with ruthenium can reduce catalyst loading while maintaining performance. However, these designs must be carefully engineered to ensure that stability is not compromised. Ruthenium, for example, offers high catalytic activity but lower stability, so its use requires precise control to achieve long-term durability.

In real-world operation, additional stress factors such as fluctuating power input, start-stop cycles, and load changes can accelerate degradation. These dynamic conditions place further demands on catalyst materials and make stability even more critical.

For this reason, durability is not only a question of material selection, but also of validation. Accelerated degradation testing and long-term performance data are essential to ensure that catalytic activity, conductivity, and electrode structure are maintained over time.

In summary, catalyst materials determine how well PEM electrolysis systems can sustain performance under harsh and dynamic conditions. Only materials that combine catalytic activity, conductivity, and stability can deliver the long lifetimes required for industrial hydrogen production.

Dihydrogen hexachloroiridate(IV)