The cost of hydrogen cars that emit only water as exhaust could be significantly reduced following a recent discovery at the University of Copenhagen.

Researchers have found a way to cut the amount of the costly metal platinum that is needed in the hydrogen fuel cell.

“By placing the platinum differently inside the fuel cell we can dramatically reduce the amount of platinum that is needed,” Matthias Arenz, an associate professor at the Department of Chemistry at the University of Copenhagen, told science news site Videnskab.dk. “That means the fuel cells will become much cheaper to make.”

According to Videnskab.dk, the fuel cells transform hydrogen and oxygen into electricity and water using a chemical reaction. This is both a quiet process and one that can be reversed so that renewable energy can be stored as hydrogen for later use.

Platinum acts as a catalyst in the fuel cell and speeds up the chemical process, but its high value pushes up the costs. Up to 100 grammes of platinum are currently needed to catalyse the reaction, but this needs to be brought down to around 10 grammes if the fuel cells are to become more widespread.

“The goal is to use the platinum as effectively as possible so that we can bring it down to around a fifth or a tenth of what is currently needed,” Arenz said.

Arenz and his team managed to make the platinum a more efficient catalyst by arranging it differently in the fuel cell and giving it a higher surface area. This means that the same amount of platinum can do more work, making it far more efficient.

“The next step will be to scale up our experiment so that we can actually make a fuel cell,” Arenz said.