Iridium (Ir): Key Metal for the Hydrogen Economy

Iridium (chemical symbol: Ir, atomic number 77) is a silvery-white, extremely hard and dense transition metal from the platinum group. It was discovered in 1803 by the English chemist Smithson Tennant and named after the Greek goddess Iris — because of the colourful compounds it forms.

Iridium is the most corrosion-resistant of all known metals and one of the rarest elements in the Earth's crust. It occurs mainly as a byproduct of platinum and nickel mining and is used in high-performance applications due to its exceptional physical properties — from aerospace to hydrogen electrolysis.

Although iridium is one of the rarest elements, it plays an indispensable role in numerous high-tech industries. Its unique combination of hardness, heat resistance, and chemical inertness makes it the material of choice for the most demanding applications.

Spark plugs and automotive: Iridium spark plugs are the gold standard in modern engines. The extremely fine iridium electrode enables a more precise spark, higher efficiency, and a lifespan of up to 100,000 km.

Hydrogen electrolysis: In PEM electrolysers (Proton Exchange Membrane), iridium serves as a catalyst for oxygen evolution. This technology is critical for the production of green hydrogen — a key element of the energy transition.

Aerospace: Iridium alloys are used in engine nozzles and high-temperature components where other materials would fail.

Iridium plays a key role in the production of green hydrogen. In PEM electrolysers (proton exchange membrane), iridium oxide serves as a catalyst on the anode side, where water is split into oxygen and hydrogen. No other material achieves the same combination of catalytic activity and long-term stability under the aggressive conditions of oxygen evolution.

The problem: global iridium production of around 7 tonnes per year is not sufficient at current loading rates to meet the projected expansion of electrolysis capacity. Germany's National Hydrogen Strategy envisions ten gigawatts of electrolysis capacity by 2030 — globally, only around five gigawatts currently exist. Each of these electrolysers requires iridium.

Research is therefore working on two fronts: first, on reducing iridium loading per electrolyser — researchers at Fraunhofer IAP developed catalysts in 2025 that achieve the same performance with one quarter of the previous iridium content [1]. Second, on single-atom catalysts, where iridium atoms are specifically distributed on carrier materials to further minimise precious metal usage [2].

Are there alternatives to iridium?

The most promising candidate is ruthenium — another platinum group metal that is roughly 7.5 times cheaper than iridium and has higher catalytic activity [3]. The problem: pure ruthenium dioxide dissolves after only a few hundred hours under the aggressive conditions of PEM electrolysis, while iridium remains stable for tens of thousands of hours. Recent breakthroughs show, however, that ruthenium can be significantly stabilised through doping with nickel, manganese, or tungsten — researchers at Rice University achieved over 1,000 hours of operation under practical conditions with a nickel-stabilised ruthenium catalyst for the first time [3]. Mixed catalysts of iridium and ruthenium are already commercially available and reduce iridium demand by up to 30% [4].

Completely iridium-free solutions based on transition metals such as manganese, cobalt, or iron currently exist only at laboratory scale — they dissolve too quickly in the acidic environment of PEM electrolysis [5]. In the short term, iridium will therefore remain indispensable. The question is not whether iridium will be replaced, but how much demand per electrolyser can be reduced — and whether this efficiency gain keeps pace with the planned expansion of electrolysis capacity.

For investors, this dynamic means: industrial demand for iridium is rising structurally — regardless of whether loading per electrolyser decreases, because the total number of installed electrolysers is set to grow massively. Iridium thus stands at the centre of a bottleneck that directly affects the energy transition.

Although both belong to the platinum group, iridium and platinum differ significantly in their properties, availability, and areas of application. This comparison is particularly insightful for investors and collectors.

For a detailed comparison of all precious metals — including osmium and rhodium — see our precious metals comparison.