Iron Catalysts Make Hydrogen Fuel Cells Practical

Hydrogen Fuel Cells: Iron Catalysts as a Platinum Alternative

Hydrogen could, in theory, be the perfect fuel for a green future: It can be produced from renewable electricity, does not produce any pollutants when consumed, and requires only water as a material for its production.

However, producing hydrogen at a low enough cost has been challenging. Alternative systems, like co-production of freshwater at the same time, new hydrogen catalysts that do not require precious metals, or photocatalysis, are being explored.

Another step that reduces the commercial viability of hydrogen is at the consumption stage. When not used in a combustion engine (similar to a fuel engine, with lower efficiency), fuel cells are used, which usually require expensive platinum as a catalyst.

Not only does this make fuel cells more expensive, but it also could hinder the mass adoption of hydrogen as a fuel, as platinum and the associated metals like palladium are very rare on Earth, making a surge in their production difficult to achieve.

Luckily, alternatives are coming, thanks to the work of Chinese scientists at many of the top research institutions of the country: the Chinese Academy of Sciences, Shenzhen University (China), Southeast University (China), Tsinghua University, Beijing University of Chemical Technology, City University of Hong Kong, and Xiamen University.

They published¹ the discovery of a new iron-based catalyst for fuel cells in the prestigious scientific journal Nature, under the title “Acidic oxygen reduction by single-atom Fe catalysts on curved supports”.

How Fuel Cells Work

The parts of fuel cells that generate electricity from the consumption of hydrogen are the proton exchange membranes (PEMs).

Fuel cells work by catalyzing the conversion of hydrogen (H₂) into protons (H+ ions) + electrons, creating an electrical current. As mentioned before, this catalyst is traditionally platinum, an expensive metal.

Source: Wikipedia

Instead, the Chinese scientists have created a new catalyst design, described as “inner activation, outer protection”, which relies on simple iron as a catalyst.

Iron-Based Hydrogen Catalysts

Challenges of Iron Catalysts in Fuel Cells

The idea of using an iron catalyst, naturally able to capture oxygen (a tendency we commonly know as “rust”) and to tie it to the hydrogen ions, is not novel.

But so far, it has been hindered by unwanted chemical reactions, notably the strong adsorption of oxygenated reaction intermediates, and the demetallization of iron atoms. So either the iron atoms get “stuck” with oxygen-rich compounds, or they become unable to work as a catalyst.

In order to stop these unwanted reactions, the researchers created a unique nanostructure for the iron catalyst.

Nanostructured Hollow Iron Catalysts

Traditional iron catalysts rely on an outer surface of graphene or carbon supports, limiting the amount of iron accessible for the desired reactions with hydrogen.

Instead, the method used was to create an inner curved surface with a single-atom iron catalyst site.

Each of these sites is located in a nanoconfined hollow multishelled structure (HoMS). These nano HoMS are spread over and bound to a 2D carbon layer, similar to graphene.

Source: Research Gate

The nano hollow particles are about 10 nm × 4 nm in size, and consist of multiple shells where iron atoms are concentrated on the inner layers at high density. Synchrotron X-ray absorption spectroscopy revealed that these inner Fe atoms are at a 57.9% rate in a catalytically active state.

Source: Research Gate

Performance Gains With Iron Catalysts

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The nanostructure weakens the binding strength of the oxygenated reaction intermediates, removing a major limitation of iron-based catalysts.

Source: Research Gate

It also reduces the hydroxyl radical (•OH) production rate, a very reactive and damaging molecule that is always a potential problem in oxygen-hydrogen reactions.

The final result is a fuel cell using iron catalysts that is radically superior to other designs, both in terms of peak power density and in current density (red stars below), with a record high power density of 0.75 W cm−2 under 1.0 bar H2–air.

Source: Research Gate

This catalyst design is also much more durable than the previous iteration of iron-based catalysts, staying at an 86% efficiency after more than 300 hours of operation.

Source: Research Gate

Conclusion

A hydrogen economy will only be possible when the economic considerations have been solved, with easy-to-produce catalysts, relying on abundant and cheap materials.

In that context, iron, being one of the most produced and cheapest metals on earth, would be an ideal candidate.

It also means the relatively quick degradation of efficiency over time (which could likely still be improved over that first experimental design) would be less of an issue, and the catalyst part of the fuel cell could just be swapped with a new one regularly, with the used one recycled or regenerated to its original performance.

Investing in Fuel Cell Technology

Plug Power Inc.

Plug Power is a leader in green hydrogen, with a focus on fuel cells. The company reports 72,000+ fuel cells installed across 300+ locations, with a large footprint in material-handling fleets. In particular, its fuel cells power over 40,000 forklifts and, with revenues up x8 since 2013.

It is also active in building hydrogen infrastructure, like hydrogen production, logistics, utility-scale power generation, and deliveries.

Source: Plug Power

The company is aiming for scale to reduce hydrogen production costs from $10/kg to $4/kg, while multiplying production by 14x in 2027. It should also replace all the externally sourced hydrogen, which was often resold to customers at a loss.

Due to the massive investments to increase production capacity 19x since 2020, the company is not profitable yet, but progress in sourcing its own hydrogen should change that.

The company sees its solutions as either a direct mobility fuel or a complement to EVs, as hydrogen allows for the reduction of the pressure on the grid during EVs’ peak charging time, which does not match the periods of production of renewables during the day.

Source: Plug Power

As a major producer of fuel cells, Plug Power would greatly benefit from a shift toward a hydrogen-based economy. A cheaper fuel cell catalyst could be integrated into its designs, and boost the adoption rate of hydrogen vehicles and grid-scale energy storage.

So this makes Plug Power a good stock to bet on a turn toward hydrogen in general, with a growth in demand for its fuel cells each time a cheaper method to produce, store, transport, or utilize hydrogen is invented.

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Study Referenced

^{1. Zhao, Y., Wan, J., Ling, C. et al. Acidic oxygen reduction by single-atom Fe catalysts on curved supports. Nature 644, 668–675 (2025). https://doi.org/10.1038/s41586-025-09364-6}