With a history dating back to 1660, Heraeus has spent nearly four centuries investing in and developing crucial technologies for industry, the environment, and health. One of Its current goals is based on precious metals, to help the world secure net zero by 2050. We spoke to Dr Christian Gebauer, head of Hydrogen Systems, part of Heraeus Precious Metals New Business Development, about the contribution Heraeus is making to fuel cell vehicles, recycling, and more.
“Heraeus is a company with a long and rich history, but our work has always been looking forward. Primarily, right now, in Heraeus Precious Metals we’re working toward a more efficient use of precious metals, and to reduce our carbon footprint in order to contribute to fighting the climate change.”
Dr Christian Gebauer, head of Hydrogen Systems at Heraeus, tells The Hydrogen Standard that there are three primary areas in which the company’s efforts are now directed.
Image 1:Example of a Fuel Cell
Heraeus Precious Metals is the global business unit of the Heraeus group that is mainly specialised on precious metals. Firstly, with precious metals trading, there is the provision of precious metals to the industry and markets. Then, there are all kind of precious metal-based products in a huge variety of industries and applications. And finally, there is a commitment to precious metals recycling in order to achieve sustainability and manage the scarce raw materials in the cycle.
Dr Gebauer’s personal responsibility is research, and his focus is largely on proton-exchange membrane (PEM) electrolysers and fuel cells, applications that play an important role in the hydrogen ecosystem. Thanks to a large testing site, where Christian’s team can study the behaviour and applications of precious metals, they’re hoping to make breakthroughs with serious implications for the hydrogen industry.
“For example, in order to generate hydrogen out of water,” he explains, “you need a catalytic conversion. And those catalysts are built with precious metals—something we obviously have a lot of experience in. A such, we believe that we are well positioned to supply these components to the hydrogen economy.”
Even if Heraeus isn’t directly involved in the energy transition, the company will play an absolutely crucial role, nonetheless. While governments will provide a wider roadmap for the energy transition—including the move toward hydrogen—businesses like Heraeus need to implement strategies to make the component supply work.
“You can’t trick physics”
That’s why Heraeus is focusing largely on PEM electrolysis, a technology that’s crucial for hydrogen generation. However, even with state-of the art use of precious metals there isn’t sufficient supply of precious metals to enable Europe to meet its goals for electrolyser capacity, as Dr Gebauer explains.
“PEM electrolysers use iridium catalysts. Europe alone is planning to build 40GW of electrolyser capacity by 2030, and there is simply not enough iridium around to produce so many electrolysers in the way that they’re currently being built. Thus, we need to work on the levels of iridium required. And this is exactly what we do: Heraeus is trying to find ways to reduce the amount of iridium that each application uses. For achieving the target, the reduction of costs and raw materials is crucial”
Dr Gebauer’s research goes down to the cellular level to improve these efficiencies—as different precious metals affect the way that the electrolysis works.
“One of the main challenges is choosing the active metal in the catalyst. This decision depends on so many different parameters. Iridium, for example, is very active, but it’s quite slow compared to Ruthenium which is even more active—but has stability issues. However, since Electrolysers are likely to run for 20 years or more, stability is really important.”
“This is why,” Dr Gebauer continues, “manufacturers usually try to be on the safe side and use Iridium, not Ruthenium. But they want to make sure that the process works, so they use more iridium than is actually needed. Recent data, for example, shows that up to one gram of iridium are typically used per kilowatt. Given the scarcity of iridium, that’s just too much if these electrolysers want to be rolled out globally.”
Instead, Christian suggests that using iridium oxide can help stability and efficiency, so that as little as a fifth of typical iridium levels are used. With the latest low-iridium solutions of Christian’s lab the amount of iridium can be further reduced without compromising the activity levels. ”Actually”, he says, “each electrolyser shouldn’t be using more than 0.2 grams of iridium per kilowatt. Thanks in part to Heraeus, that’s now possible.”
“Ultimately, balancing efficiency with other factors remains a challenge. You can’t trick physics, but you can look for ways to get as much out of the material as possible.”
Image 2: Platinum Sponge
The problem of platinum and passenger cars
As the applications of different precious metals change, demand will change too. Into the future, it was imagined that millions of fuel cell cars would begin to hit the road, each demanding their own precious metal catalyst. This predicted boom in fuel cell cars has not quite been realised—yet. However, the need to improve efficiencies in this hardware remains as important as ever.
“Most fuel cell systems are platinum-based,” Christian says, “although there are some systems that use a second metal. The most important thing is to improve the output, but this is easier said than done, as there are so many different factors that affect this — from vehicle usage to power demands to the way that the system physically fits into the vehicle.”
In this respect, there’s still a long way to go to improve hydrogen fuel cells for vehicle use.
“Honestly, for passenger cars, I think battery electric vehicles will always have better efficiency than fuel cells,” Christian admits.
“That’s simply because batteries don’t require an energy conversion. But fuel cells still have their use. Over longer distances they’re great, because refuelling times are lower. We expect fuel cells to increase, particularly if China gets on board. And for other transport options, such as aviation or maritime applications, they also hold a lot of potential.”
Beyond fuel cells
However, it’s not only PEM electrolysers and fuel cells that Heraeus works with. Rather, Heraeus is engaged with many other parts of the hydrogen value chain. For example, Heraeus is engaged with gas purification catalysts, in which precious metals are required, as well as hydrogen storage and transport, for example involving ammonia.
“Specifically, we’re looking into the process in which hydrogen gas is converted into liquids so hydrogen can be transported,” Christian says.
Transportation of hydrogen is crucial for mobile applications, especially when there is no re-fill possibility just around the corner. Think of maritime, where for long distances there is no possibility to recharge batteries or refuel. For this kind of applications R&D is working on storing the hydrogen atoms within ammonia. To transform the hydrogen to ammonia and then back into hydrogen again, precious metals catalysts are applied.
Beyond the catalysts itself, Heraeus is also working to improve recycling processes for electrolysers and fuel cells. Currently, getting fuel cells back from the market for recycling is not well structured, and a new strategy will be needed. “Bringing end of life materials back into the loop will be a crucial aspect to manage the supply and has to be part of a raw material strategy for the hydrogen ramp up.”
But Christian is confident.
“From our perspective, we are already well developed in managing the recycling of precious metals throughout the hydrogen value chain. We’re excited to make it happen, for a more sustainable future.”