Platinum-Free Catalyst Makes Clean Hydrogen Cheaper and More Durable

Clean hydrogen just got a meaningful cost cut. A team of engineers at Washington University in St. Louis has unveiled a new catalyst for splitting water into hydrogen and oxygen that works without platinum group metals — the scarce, expensive materials that have long kept renewable hydrogen out of reach for large-scale industrial use.

The research, led by Gang Wu, professor of energy, environmental and chemical engineering in the McKelvey School of Engineering, was published in May 2026. It targets a piece of hardware called an anion-exchange membrane water electrolyzer, or AEMWE — a device that uses electricity from solar, wind, or hydropower to break water molecules apart and capture the resulting hydrogen as a fuel.

The problem with conventional electrolyzers is the price tag of their catalysts. Most commercial systems rely on platinum or other platinum group metals to speed up the hydrogen reaction. Those metals are rare, geopolitically concentrated, and expensive enough to put a hard ceiling on how cheap green hydrogen can ever become.

Wu's group replaced them with a composite of two more abundant materials: rhenium phosphide and molybdenum phosphide. The combination behaves like a tag team. The rhenium component helps hydrogen atoms attach to the catalyst surface and then release as gas. The molybdenum component accelerates the splitting of water in the alkaline electrolyte. Together, they extract hydrogen more efficiently than the platinum-based cathodes the team benchmarked against.

The durability numbers are the headline. Paired with a nickel-iron anode, the catalyst kept running for more than 1,000 hours at industrial-strength current densities of 1 and 2 amperes per square centimeter. Wu says that makes it one of the most durable platinum-free cathodes ever developed for anion-exchange membrane electrolyzers — and it had the lowest resistance of any catalyst in the study across the tested voltage range.

"Going from water to hydrogen is a very desirable way we are able to store energy for different applications," Wu said. "Hydrogen itself can be used as an energy carrier and is useful for different chemical industries and manufacturing."

Green hydrogen is one of the few pathways for cleaning up sectors that resist easy electrification: steelmaking, fertilizer production, long-haul shipping, and high-temperature industrial heat. Today, almost all of the world's hydrogen is "gray," made by splitting natural gas in a process that emits carbon dioxide. Hydrogen produced by electrolysis powered by renewables emits nothing at the point of production — but it has historically cost two to three times more than the fossil version, with platinum being one reason why.

Dropping platinum from the cathode does not single-handedly solve that gap, but it removes one of the biggest material constraints on scaling AEMWE technology. Anion-exchange membrane systems are already considered the most promising bridge between today's alkaline electrolyzers, which are cheap but slow, and proton-exchange membrane electrolyzers, which are fast but expensive. A platinum-free, long-lived cathode brings AEMWEs closer to combining the strengths of both.

The team is now working on scaling up the catalyst and confirming that its performance holds at larger surface areas — the step that historically separates a promising lab result from a real industrial product. With more than 1,000 hours of stable operation already on the books and a clear cost advantage over platinum, the WashU catalyst joins a growing list of breakthroughs nudging green hydrogen toward the price point where industry simply prefers it.