According to a statement, the majority of hydrogen fuel cells use catalysts made of platinum, which is rare and expensive. There are few alternatives because most elements can’t endure the fuel cell’s highly acidic solvents present in the reaction that converts hydrogen’s chemical energy into electrical power.
Platinum and iridium can resist the corrosive process but they are impractical for large-scale use due to their scarcity and cost.
Gold and palladium can similarly cope in the corrosive environment of a fuel cell but are not suitable with the chemical reaction — a situation that UCF’s Prof Sergey Stolbov and postdoctoral research associate Marisol Alcántara Ortigoza sought to rectify.
They did so by creating a sandwich-like structure that layers cheaper and more abundant elements with gold and palladium and other elements to make it more effective.
The outer monoatomic layer is either palladium or gold. Below it is a layer that works to enhance the energy conversion rate but also acts to protect the catalyst from the acidic environment. These two layers reside on the bottom slice of the sandwich — an inexpensive substrate (tungsten), which also plays a role in the stability of the catalyst.
‘We are very encouraged by our first attempts that suggest that we can create two cost-effective and highly active palladium — and gold-based catalysts — for hydrogen fuel cells, a clean and renewable energy source,’ said Stolbov.
By creating these structures, more energy is converted; and because the more expensive and rare metals are not used, the cost could be significantly less.
Stolbov said experiments are needed to test the predictions, but he says the approach is quite reliable. He is already working with a group within the US Department of Energy to determine whether the results can be duplicated and have potential for large-scale application.
Stolbov’s work was recently published in The Journal of Physical Chemistry Letters.