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Hydrogen cars’ reliance on large amounts of platinum – about 50g, compared to roughly 5g in a typical vehicle – is one of the reasons they are still so rare, according to the team at the University of Copenhagen in Denmark. Only 100 tonnes of platinum are mined annually, in South Africa.
“We have developed a catalyst which, in the laboratory, only needs a fraction of the amount of platinum that current hydrogen fuel cells for cars do,” said Professor Matthias Arenz. “We are approaching the same amount of platinum as needed for a conventional vehicle. At the same time, the new catalyst is much more stable than the catalysts deployed in today's hydrogen powered vehicles.”
A press release announcing the research did not quantify the reduction, but Professor Jan Rossmeisl told Professional Engineering that they reduced platinum by a factor of eight in laboratory experiments.
“It is not trivial to take that and bring that into a car,” he warned, but added: “If you can have an amount of platinum that approaches the 5g that they use now, then it could be scalable. If that number is exactly 10g or 5g [we don’t know yet,] but effectively if that’s possible to take that into a real fuel cell and do it at a scalable level, that would be really great. A factor of eight takes you close to 5g.”
To have as much surface area as possible, current catalysts are based on platinum-nano-particles which are coated over carbon. Unfortunately, carbon makes catalysts unstable.
To tackle the issue, the team developed a carbon-free catalyst. Instead of nano-particles, the researchers created a network of nanowires characterised by an abundance of surface area and high durability.
The new catalyst makes it possible to produce more horsepower per gram of platinum, making the production of hydrogen fuel cell vehicles more sustainable.
“The new catalyst can make it possible to roll out hydrogen vehicles on a vastly greater scale than could have ever been achieved in the past,” said Professor Rossmeisl.
The team now aims to scale up the results so the technology can be implemented in hydrogen vehicles.
“We are in talks with the automotive industry about how this breakthrough can be rolled out in practice. So, things look quite promising,” said Professor Arenz.
The research was published in Nature Materials.
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.