image: Characterizations of CoP|F-20 and CoP. a) Schematic synthetic illustration of CoP|F on CFP. b) SEM image of CoP|F-20 nanosheets on a single carbon fiber. Scale bar, 2 µm. c) A false-color TEM image of a typical CoP|F-20 nanosheet, showing its relative thickness. Scale bar, 100 nm. d) Atomic-resolution STEM images of CoP|F-20. Scale bar, 1 nm. Inset up right shows the corresponding FFT pattern, and down left shows crystal structure along [101̄] zone axis. e STEM-EDX elemental mapping of CoP|F-20, showing the homogeneous distribution of Co (green), P (blue), and F (red). Scale bar, 200 nm. HAADF-STEM images of CoP|F-20 f and CoP g, and corresponding integrated pixel intensities h of spacings along (201) facet. Scale bar, 1 nm. i) Co 2p and j) P 2p XPS spectra of CoP|F-20 and CoP catalysts. k XANES spectra at Co K-edge of CoP|F-20, CoP, and Co foil. l) R-space curve-fitting of EXAFS spectra of CoP|F-20 and CoP.
Credit: ©Heng Liu et al.
The hydrogen evolution reaction (HER) is a remarkable process that can create clean hydrogen fuel - a potential part of a solution to our climate change crisis. The problem lies in scaling up this reaction from a lab experiment to large scale commercial production, while keeping costs down.
The findings were published in Advanced Energy Materials on April 3, 2025.
In their search for superior HER performance, researchers at Tohoku University demonstrated that a surface reconstruction pathway can produce durable non-noble metal-based cathodes that speed up the HER reaction. They can maintain their performance for more than 300 hours and are calculated to cost very close to the US Department of Energy's 2026 H2 production target ($2.00 per kgH2-1). This could pave the way for the rational design of brand new, highly-efficient non-noble metal-based cathodes for commercial PEM application - finally bridging the gap from laboratory to factory.
The angle this study approached for trying to improve the HER - which tends to be inefficient and slow by nature - was transition metal phosphides (TMPs). This promising catalyst (which improves the HER's efficiency) is a durable and cost-effective non-noble metal. However, typically noble metals are used, so the researchers recognized that there was a knowledge gap about non-noble metals that needed to be filled.
The research team prepared F modified CoP and examined aspects such as its surface reconstruction and true active sites using operando X-ray absorption spectroscopy (XAS) and Raman measurements. Essentially, adding the F in the CoP1-x lattice allows for P-vacancy sites to form on the surface, which leads to more active sites that are able to speed up the HER.
"This reconstructed Co is highly active, works in acidic conditions, and can maintain approximately 76 W for over 300 hours," says Heng Liu (Advanced Institute for Materials Research (WPI-AIMR)). "We're getting close to an affordable method to produce fuel. The calculated cost of using this method is $2.17 per kgH2-1 - just 17 cents over the current production target set for 2026."
The researchers found that when this F modified CoP cathode underwent surface reconstruction, its activity was improved. The experiment doesn't just test the setup in a lab-scale experimental setup with three electrodes, but also extends the findings to commercial-scale PEM electrolyzers. These results are significant advancements in HER catalyst research that could be the basis for the rational design of other non-noble metal-based cathodes.
"We're always thinking about the end goal, which is for research to make its way into everyday life. This advancement brings us one step closer to designing more realistic options for commercial PEM application," says Liu.
About the World Premier International Research Center Initiative (WPI)
The WPI program was launched in 2007 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).
See the latest research news from the centers at the WPI News Portal: https://www.eurekalert.org/newsportal/WPI
Main WPI program site: www.jsps.go.jp/english/e-toplevel
Advanced Institute for Materials Research (AIMR)
Tohoku University
Establishing a World-Leading Research Center for Materials Science
AIMR aims to contribute to society through its actions as a world-leading research center for materials science and push the boundaries of research frontiers. To this end, the institute gathers excellent researchers in the fields of physics, chemistry, materials science, engineering, and mathematics and provides a world-class research environment.
AIMR site: https://www.wpi-aimr.tohoku.ac.jp/en/
Journal
Advanced Energy Materials
Article Title
Affordable Hydrogen Fuel Production Using Surface Reconstruction Strategy
Article Publication Date
3-Apr-2025