Oven-temperature process (~300℃) boosts catalyst performance sixfold

A research team from Pohang University of Science and Technology (POSTECH) and Seoul National University has developed a new method to activate water-splitting catalysts at an oven temperature of just 300 °C—much lower than the conventional furnace temperature of 800 °C. This low-temperature process also boosts the catalyst’s oxygen evolution efficiency by nearly sixfold. The study, led by Prof. Yong-Tae Kim and Dr. Sang-Mun Jung of POSTECH and Prof. Junwoo Son and Dr. Youngkwang Kim of Seoul National University, was recently published in the journal Advanced Functional Materials. Recognizing the significance of this breakthrough, the journal featured the research as its cover article on July 17.

Solar and wind power generate electricity that fluctuates with the weather. Hydrogen offers a solution to store this excess energy. Using electricity to split water into hydrogen and oxygen allows the energy to be stored and later converted back into electrical power—enabling long-term large-scale energy storage.

However, the oxygen evolution reaction (OER) at the anode of water electrolyzers requires a high overpotential due to the sluggish kinetics of its multistep electron-transfer process. Electrocatalysts are used to accelerate the reaction, and consequently, extensive efforts have been devoted toward the development of highly active electrocatalysts for OER.

The team focused on a type of material called a perovskite, which is stable and easy to modify. However, its relatively large particle size (>100 nm) limits its catalytic activity. To overcome this, the researchers used a method called ‘Exsolution’, where metal ions in the perovskite lattice migrate to the surface and form nanoscale active particles. Normally, exsolution requires heating above 800 °C for several hours. However, by applying a technique called bead milling, the researchers achieved the same effect at just 300 °C. Bead milling grinds the material using microscopic beads, breaking it into fine particles and loosening its internal structure. This makes it easier for the metal ions to reach the surface.

The exsolved electrocatalyst generates oxygen nearly six times more efficiently than the original perovskite catalyst, while significantly reducing energy costs. This makes the method more suitable for large-scale production of hydrogen from renewable energy.

“This study marks a major step toward developing high-performance, low-cost catalysts for water electrolysis,” said Prof. Kim. “Controlling structure at the nanoscale will be key to improving system efficiency.” The research was supported by the Ministry of Science and ICT through the H2NEXTROUND and the Nano Materials Technology Development Program.