image: Synthesis and characterization of the Co2Mo3O8 precatalyst. (a) Schematic illustration of the preparation route for developing pristine Co2Mo3O8, where CoMo-P, CoMo@ZIF-67-P, and Co/CoO @Co2Mo3O8 represent various precursors or intermediates for synthesizing Co2Mo3O8. (b) X-ray diffraction (XRD) pattern, (c) scanning electron microscopy (SEM) image, (d) atomic force microscopy (AFM) image, (e) transmission electron microscope (TEM) image, (f) high-resolution TEM(HRTEM) image (insets are the corresponding structural illustration and the fast Fourier transform (FFT) pattern, Z.A. represents zone axis), and (g) high-angle annular dark-field scanning TEM(HAADF-STEM) image and energy dispersive X-ray spectroscopy (EDX) elemental mapping images of Co2Mo3O8.
Credit: ©Heng Liu
In order to meet our goals for carbon neutralization by the 2050s, we need environmentally friendly fuels. Catalysts (and their precursor, precatalysts) are key components in the electrochemical water-splitting reaction that produces clean hydrogen fuel.
Researchers at Tohoku University produced a highly stable catalyst that could feasibly be used in practical, real-world applications. To develop their catalyst, they looked at a complicated chemical and electrochemical process called "reconstruction." During catalysis, a precatalyst undergoes a reconstruction that changes its features, and either improves or impairs its catalytic activity. Reconstruction can be affected by multiple factors, including the properties of the precatalyst and electrolyte, the electrochemical induction method, or reaction temperature - making it difficult to identify the precise reconstruction mechanisms.
"It's hard to design a catalyst that works well when that catalyst itself can change. It's almost like trying to play tennis with a ball that morphs each time you hit it," says Heng Liu (Tohoku University), "Therefore, there are a lot of challenges to develop a rational and commonly applicable methodology for synthesizing high-performance catalysts."
A Co2Mo3O8 precatalyst underwent potential-dependent reconstruction, and created an electrochemically stable Co(OH)2@Co2Mo3O8 catalyst. The research team revealed that the surface structure transformation of precatalysts can be controlled by applied potentials, which is also accompanied by the etching of inherent species from the precatalyst into electrolytes.
The reconstruction of catalysts and altered electrolytes changes the entire catalysis system in such a way that performance is enhanced. The catalyst achieved a Faradaic efficiency of 99.9% versus a reversible hydrogen electrode (RHE) for hydrogen generation. Additionally, the catalyst was able to remain stable for over one month.
"In summary, the resulting catalyst was highly efficient, and able to stay in storage for extended periods of time. Our study highlights its suitability for industrial applications," says Liu.
This study advances the understanding of how precatalyst reconstruction and electrolyte evolution affects catalytic performance, which paves the way for better rational catalyst design. As catalyst design improves, it may help boost the production of clean energy sources - helping us take action against pollution and climate change.
The key experimental data and the computational structures have been made available through the Digital Catalysis Platform (DigCat), the largest experimental catalysis database to date, developed by the Hao Li Lab.
The findings were published in Nature Communications on February 22, 2025. The article processing charge (APC) was supported by the Tohoku University Support Program.
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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
Nature Communications
Article Title
Rational design of precatalysts and controlled evolution of catalyst-electrolyte interface for efficient hydrogen production
Article Publication Date
22-Feb-2025