DGIST develops eco-friendly solar hydrogen production technology

DGIST announced Friday that a research team led by Choi Jong-min, a professor in its Department of Energy Engineering, and a team led by Kim Young-hoon, a professor in the Department of Chemistry at Kookmin University, jointly developed a high-efficiency photoelectrode that produces hydrogen from sunlight using a water-based, low-voltage process.

The researchers applied a newly developed technique called "aqueous electrophoretic deposition," in which the surface molecules of nanocrystals are replaced with hydrophilic molecules that mix readily with water, and a small electric current is then applied in an aqueous solution to bond the particles to the electrode.

As a result, the process voltage dropped dramatically from 200 volts to just 4 volts — comparable to a standard battery.

The team also coated the electrode material in a safe aqueous solution in just three minutes, without toxic organic solvents, resolving surface damage and impurity formation — specifically oxidation byproducts — that had occurred under high-voltage conditions.

The newly developed photoelectrode achieved a photocurrent more than 10 times greater than that of conventional single-material electrodes.

Tests under simulated sunlight recorded a photocurrent density of 3.0 milliamperes per square centimeter.

The electrode also retained 65.1 percent of its initial performance after two consecutive hours of light exposure, and gas analysis confirmed that hydrogen was being generated normally.

The achievement is expected to contribute to the commercialization of eco-friendly green hydrogen production, as it uses materials that entirely exclude hazardous substances such as lead and cadmium and significantly reduces reliance on organic solvents and high voltages during the deposition stage.

"This research is significant in that it achieves high hydrogen production efficiency through a safe, clean, water-based low-voltage process, breaking free from the limitations of conventional methods that depended on high voltages and toxic solvents," Choi said. "It will serve as an important foundation for accelerating the practical application of eco-friendly hydrogen production technology."

The research was supported by the Ministry of Science and ICT and the National Research Foundation of Korea through their Nano and Materials Technology Development Program, as well as the ministry's Inno-Core project.

The findings, with DGIST researcher Park Jin-young and doctoral student Kim Hae-jung as co-first authors, were published in Small, an internationally renowned academic journal in the field of materials science.