The German government and the European Union have set ambitious targets for implementing the energy transition. PEM (proton exchange membrane) electrolysis, as a key technology, has a major role to play in this, as it produces green hydrogen from renewable electricity to meet the needs of industrial quantities.
To achieve the defined goals, the production of PEM electrolyzers must be brought to maturity for serial production. In order to meet the demand for catalysts in the long term, a raw materials strategy is needed for the rare iridium and platinum that are indispensable for catalyzing water splitting in an PEM electrolyzer. To address this critical requirement, the German Federal Ministry of Education and Research (BMBF) is funding the implementation of important technologies for the ramp-up of the hydrogen economy in the H2Giga flagship project.
Within the H2Giga flagship project, Heraeus is involved in two sub-projects under consortium leader Siemens Energy to achieve maturity for serial production. Specifically, Heraeus is responsible for closing the value cycle for the critical raw materials iridium and platinum: As one of the world’s leading precious metals experts, Heraeus is developing catalysts for PEM electrolysis with a low precious metal content and smart recycling solutions that help to solve the problem of limited raw material availability through recovery. Both approaches enable the expansion of PEM electrolysis on an industrial scale.
Catalysts based on the precious metal iridium are indispensable in PEM electrolysis. They accelerate the oxygen evolution process and thus the parallel, platinum-catalyzed generation of hydrogen.
There are a number of specific challenges to be solved when recycling these scarce raw materials. This includes the return of precious metal-containing end-of-life electrodes from PEM electrolyzers, as well as the question of how these electrodes can be processed into recyclable material on the necessary scale. In particular, substances such as fluorine make this process challenging. Additionally, the further separation and purification of iridium is highly complex and will require new, specialized technologies to achieve the highest possible yield.
"To achieve the energy transition, green hydrogen must be produced in large quantities at a competitive price level," says Christian Gebauer, Head of Innovation Hydrogen Systems at Heraeus. "We are conducting intensive research to achieve higher catalyst performance with less raw material input. At the same time, we are working to advance the technology and capacity for recycling these critical raw materials. For series production, it is essential to take care of the raw material chain in a timely and sustainable manner."
