Reviewed by Lexie CornerJan 21 2025
A study published in the Journal of Materials Chemistry A by researchers at POSTECH presents a method to address key challenges in clean hydrogen production using microwaves. The approach aims to improve efficiency and overcome limitations in existing technologies.
Schematic illustration of oxygen release upon interaction with microwaves (left) and a corresponding graph of oxygen release and uptake (right). Image Credit: Pohang University of Science and Technology
Clean hydrogen has become a key focus for next-generation energy systems due to its low carbon footprint. However, conventional hydrogen production methods face significant challenges. Thermochemical processes, which use oxidation-reduction reactions in metal oxides, require extremely high temperatures, often exceeding 1,500 °C. These methods are energy-intensive, costly, and difficult to scale, limiting their feasibility for widespread use.
To address these limitations, the POSTECH team explored the use of microwave energy, a well-known but underutilized energy source commonly used in household microwave ovens. The team demonstrated that microwave energy could reduce the reduction temperature of Gd-doped ceria (CeO₂), a benchmark material for hydrogen production, to below 600 °C, a reduction of over 60 %. This process replaced 75 % of the thermal energy typically required, significantly improving energy efficiency.
The researchers also observed enhanced formation of "oxygen vacancies," structural imperfections critical for splitting water into hydrogen. Conventional methods often require prolonged exposure to extreme temperatures to generate these vacancies. Using microwave technology, the POSTECH team achieved the same results in minutes at temperatures below 600 °C. A thermodynamic model further validated the process and provided insights into the underlying mechanism driving the microwave-assisted reaction.
This research has the potential to revolutionize the commercial viability of thermochemical hydrogen production technologies. It will also pave the way for the development of new materials optimized for microwave-driven chemical processes.
Hyungyu Jin, Professor, Pohang University of Science and Technology
Professor Gunsu Yun added, “Introducing a new mechanism powered by microwaves and overcoming the limitations of existing processes are major achievements, made possible through the close interdisciplinary collaboration of our research team.”
This research was funded by the Circle Foundation's Innovative Science and Technology Program, the Ministry of Science and ICT's Mid-Career Researcher Program, POSTECH's Basic Science Research Institute, and the Ministry of Trade, Industry, and Energy.
Journal Reference:
Lee, D., et al. (2024) Thermodynamic assessment of Gd-doped CeO2 for microwave-assisted thermochemical reduction. Journal of Materials Chemistry A. doi.org/10.1039/d4ta05804f.