multi-institutional team led by the US Department of Energy’s (DOE) Argonne National Laboratory (ANL) has developed a low-cost cobalt-based catalyst for the production of hydrogen in a proton exchange membrane water electrolyzer (PEMWE). Other contributors include DOE’s Sandia National Laboratories and Lawrence Berkeley National Laboratory, and Giner Inc..
Proton exchange membrane electrolyzers run with separate catalysts for each of the electrodes (cathode and anode).
The cathode catalyst yields hydrogen, while the anode catalyst forms oxygen. The anode catalyst uses iridium, which has a current market price of around US$5,000 per ounce. The lack of supply and high cost of iridium pose a major barrier for widespread adoption of PEM electrolysers. The main ingredient in the new catalyst is cobalt, which is said to be substantially cheaper than iridium.
Giner Inc., a leading research and development company working toward commercialisation of electrolyzers and fuel cells, has evaluated the new catalyst using its PEM electrolyzer test stations under industrial operating conditions. The performance and durability far exceeded that of competitors’ catalysts.
Important to further advancing the catalyst performance is understanding the reaction mechanism at the atomic scale under electrolyzer operating conditions. The team deciphered critical structural changes that occur in the catalyst under operating conditions by using X-ray analyses at the Advanced Photon Source (APS) at Argonne. They also identified key catalyst features using electron microscopy at Sandia Labs and at Argonne’s Center for Nanoscale Materials (CNM). The APS and CNM are both DOE Office of Science user facilities.
In addition, computational modelling at Berkeley Lab has revealed important insights into the catalyst’s durability under reaction conditions.
The team’s achievement is a step forward in DOE’s Hydrogen Energy Earthshot initiative. 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. Key applications include international grid power generation and residential and commercial heating.
Di-Jia Liu, senior chemist at Argonne, explains: “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.”
Research teams deciphered critical structural changes that occur in the catalyst under operating conditions by using X-ray analyses at the Advanced Photon Source (APS) at Argonne. They also identified key catalyst features using electron microscopy at Sandia Labs and at Argonne’s Center for Nanoscale Materials (CNM). The APS and CNM are both DOE Office of Science user facilities.
“We imaged the atomic structure on the surface of the new catalyst at various stages of preparation,” comments Jianguo Wen, an Argonne materials scientist.