Argonne, UChicago scientists create low-cost way to make clean hydrogen fuel

A plentiful supply of clean energy is lurking in plain sight. Hydrogen can power vehicles while emitting nothing but water; it is also an important chemical for many industrial processes, most notably in steel-making and ammonia production.

As part of the quest to combat climate change, scientists are seeking low-cost methods for producing hydrogen from water to replace fossil fuels. To be truly clean, this process needs to be done using renewable energy.

A multi-institutional team led by Argonne National Laboratory, a U.S. Department of Energy lab affiliated with the University of Chicago, has developed a low-cost catalyst for a process that yields clean hydrogen from water.

“Our results establish a promising path forward in replacing catalysts made from expensive precious metals with elements that are much less expensive and more abundant,” said study author Di-Jia Liu, a senior chemist at Argonne who holds a joint appointment in the Pritzker School of Molecular Engineering at the University of Chicago.

Removing the bottleneck

The process to split water into hydrogen and oxygen is called electrolysis, and it has been around for more than a century.

In earlier days, the technique for this process used a lot of energy. But a new generation of technology for this process, known as proton exchange membrane electrolyzers, can run with higher efficiency at near room temperature. The reduced energy demand makes them an ideal choice for producing clean hydrogen by using renewable but intermittent sources, such as solar and wind.

However, cost remained a problem. One of the catalysts in that process uses iridium, which has a current market price of around $5,000 per ounce. The lack of supply and high cost of iridium pose a major barrier for widespread adoption of PEM electrolyzers.

The team was able to develop a new catalyst whose main ingredient is cobalt, which is substantially cheaper than iridium.

“By using the cobalt-based catalyst prepared by our method, one could remove the main bottleneck of cost to producing clean hydrogen in an electrolyzer,” Liu said.

Giner Inc., a leading research and development company working toward commercialization of electrolyzers and fuel cells, evaluated the new catalyst using its PEM electrolyzer test stations under industrial operating conditions. The performance and durability far exceeded that of competitors’ catalysts.

The team’s achievement is a step forward in the Department of Energy’s Hydrogen Energy Earthshot initiative, which mimics the U.S. space program’s “Moon Shot” of the 1960s. Its ambitious goal is to lower the cost for green hydrogen production to one dollar per kilogram in a decade. Production of green hydrogen at that cost could reshape the nation’s economy.

Applications include the electric grid, manufacturing, transportation and residential and commercial heating.

X-ray analyses

By understanding the reaction mechanism at the atomic scale under operating conditions, scientists can refine its performance.

“We imaged the atomic structure on the surface of the new catalyst at various stages of preparation,” said Jianguo Wen, an Argonne materials scientist.

The team deciphered critical structural changes that occur in the catalyst under operating condition by using X-ray analyses at the Advanced Photon Source at Argonne. They also identified key catalyst features using electron microscopy at Sandia Labs and at Argonne’s Center for Nanoscale Materials.

The Advanced Photon Source and Center for Nanoscale Materials are both DOE Office of Science user facilities. In addition, computational modeling at
Berkeley Lab revealed important insights into the catalyst’s durability under reaction conditions.

Citation: “La- and Mn-doped cobalt spinel oxygen evolution catalyst for proton exchange membrane electrolysis.” Chong et al, Science, May 12, 2023.
Funding: U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, Argonne Laboratory Directed Research and Development.

—Adapted from an article by Joseph Harmon first published by Argonne National Laboratory.