Clean hydrogen in minutes: Microwaves deliver clean energy faster

An interdisciplinary team at POSTECH, led by Professor Gunsu S. Yun, doctoral candidate Jaemin Yoo (Department of Physics, Division of Advanced Nuclear Engineering), Professor Hyungyu Jin, and doctoral candidate Dongkyu Lee (Department of Mechanical Engineering), has developed a groundbreaking technology that addresses key limitations in clean hydrogen production using microwaves. They have also successfully elucidated the underlying mechanism of this innovative process. Their findings, published as the Inside Front Cover of Journal of Materials Chemistry A, mark a transformative step in the pursuit of sustainable energy.

As the world shifts away from fossil fuels, clean hydrogen has emerged as a leading candidate for next-generation energy due to its zero carbon emissions. However, existing hydrogen production technologies face significant barriers. Conventional thermochemical methods, which rely on the oxidation-reduction of metal oxides, require extremely high temperatures of up to 1,500°C. These methods are not only energy-intensive and costly but also challenging to scale, limiting their practical application.

To address these challenges, the POSTECH team turned to a familiar yet underutilized energy source: “microwaves”¹ energy, the same source used in household microwave ovens. While microwaves are commonly associated with heating food, they can also drive chemical reactions efficiently. The researchers demonstrated that microwave energy could lower the reduction temperature of Gd-doped ceria (CeO₂)—a benchmark material for hydrogen production—to below 600℃, cutting the temperature requirement by over 60 percent. Remarkably, microwave energy was found to replace 75 percent of the thermal energy needed for the reaction, a breakthrough for sustainable hydrogen production.

Another critical advancement lies in the creation of “oxygen vacancies”², which are defects in the material structure essential for splitting water into hydrogen. Conventional methods often take hours at extremely high temperatures to form these vacancies. The POSTECH team achieved the same results in just minutes at temperatures below 600°C by leveraging microwave technology. This rapid process was further validated with a thermodynamic model, which provided valuable insight into the mechanism underlying the microwave-driven reaction.

Professor Hyungyu Jin stated, “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.” 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 study was supported 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.