Japan and California have embraced hydrogen fuel-cell technologies, a form of renewable energy that can be used in vehicles and for supplying clean energy to manufacturing sectors. But the technology remains expensive due to its reliance on precious metals such as platinum.
Engineers at Washington University in St. Louis are working on this challenge, finding ways to stabilize ubiquitous iron components for use in fuel cells to replace the expensive platinum metals, which would make hydrogen fuel-cell vehicles more affordable.
"The hydrogen fuel cell has been successfully commercialized in Japan and California in the U.S.," said Gang Wu, a professor of energy, environmental and chemical engineering at the McKelvey School of Engineering. "But these vehicles struggle to compete with the battery vehicle and combustion engine vehicle, with cost being the main issue."
A typical $30,000 gas-powered vehicle could cost $70,000 as a fuel-cell vehicle, he estimated. The platinum catalysts are the most expensive component, accounting for about 45% of the total cost of fuel cell stacks. Notably, the precious metal in fuel cells cannot benefit from economies of scale, and a significant rise in demand for fuel-cell power systems further drives up the already high price of platinum.
In research published in Nature Catalysis, Wu and his team outlined how they stabilize iron catalysts for use in the fuel cell, which would lower costs for fuel-cell vehicles and other niche applications such as low-altitude aviation and artificial intelligence data centers.
Hydrogen fuel cells work to generate electricity with zero emissions via hydrogen and oxygen, two constituent parts of water. By way of a catalyst, the two elements produce water, electricity and heat until the on-board hydrogen is depleted, while oxygen is drawn from unlimited air. People can refuel their hydrogen fuel-cell vehicles at large stations, similar to how fleets of school buses refuel at the same central station, so the refueling infrastructure challenge can be readily overcome. It's clean energy, but the precious metals used in the vehicle can add significantly to the total cost, preventing its widespread adoption.
According to the Environmental and Energy Study Institute, fuel cells can extract more than 60% of their fuel's energy while internal combustion engines recover less than 20% of gasoline's energy. That efficiency can reach 85% when the heat a fuel cell generates is also harnessed for electricity.
Unlike electric battery-run cars, people can't recharge fuel-cell vehicles using their home electricity sources. So there needs to be affordable and easily accessible hydrogen refueling infrastructure for this clean tech to take off. Making use of plentiful and affordable iron catalysts would go a long way to lowering those costs. But first, researchers needed to make iron more stable to handle the fuel-cell chemistry involved.
Wu and his team did so by creating a chemical vapor of gases that can stabilize the iron catalysts during thermal activation, an innovative approach to significantly improve catalyst stability while maintaining adequate activity in proton exchange membrane fuel cells (PEMFCs). The result vastly improved iron catalysts' durability along with increased energy density and life span. The team chose PEMFCs among different fuel types because they best serve heavy-duty vehicles, things like transport trucks, buses and construction equipment - vehicles that already go to centralized fueling centers. It's most affordable and efficient for the technology to be first adopted by heavy-duty vehicle fleets, which would further lower costs as it becomes widespread and further efficiencies of scale come on board.
"After suffering from the poor stability for decades, now we were able to address the critical problem," said Wu, who explained that next steps will include further refining their processes to make iron catalysts even better than precious metals for the fuel cells of tomorrow.
Financial support for this research includes: Washington University in St. Louis, National Science Foundation (CBET-2223467), and the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office.
Zeng Y, Qi M, Liang J, Hermann RP, Yu H, Zachman MJ, Chang CW, Lucero M, Feng Z, Cullen D, Myers DJ, Dodelet JP, Wu G. Regulating in situ gaseous deposition to construct highly durable Fe-N-C oxygen-reduction fuel cell catalysts. . Nat Catal (2026). DOI
