Hydrogen Evolution Catalyst That Can Replace Platinum Released

Ulsan National Institute of Science and Technology Develops Robust Hydrogen Evolution Catalyst Effective in Both Acidic and Alkaline Conditions
Professors Kim Geontae, Kwak Sanggyu, and Baek Jongbeom's Team Ensures Performance and Stability Regardless

From the left, Professor Kim Geontae, Researcher Yang Yejin, Professor Baek Jongbeom, Researcher Kim Jungwon.

[Asia Economy Yeongnam Reporting Headquarters Reporter Kim Yong-woo] A stable hydrogen evolution catalyst that is not affected by acids or bases has been developed.

To produce hydrogen by electrolyzing water, a catalyst that lowers the energy required for the electrochemical reaction is essential. While research on catalysts to replace the precious metal platinum (Pt) is active, a study has developed a catalyst showing excellent stability using inexpensive carbon compounds and ruthenium (Ru) metal.

The research team led by Professors Kim Geon-tae, Kwak Sang-gyu, and Baek Jong-beom from the Department of Energy and Chemical Engineering at UNIST developed a ruthenium-based catalyst with outstanding stability regardless of acidity (pH) in electrochemical reactions such as water electrolysis.

According to the research team, platinum catalysts have reduced durability in alkaline electrolytes, but the newly developed catalyst works well not only in acidic and alkaline solutions but also in neutral solutions.

Accordingly, it can also be applied to the ‘Aqueous Zinc-CO₂ system’ that captures carbon dioxide and produces hydrogen and electricity. The aqueous zinc-CO₂ system was developed in previous research by Professor Kim Geon-tae’s team, and the aqueous solution inside is saturated with carbon dioxide in a neutral state.

Pure water does not conduct electricity, so alkaline or acidic electrolytes are added to induce electrochemical reactions. The catalyst reduces the energy required for the reaction at this time.

The more the consumed energy is reduced, the more efficient the catalyst is. However, for commercial use of various electrochemical reactions such as water splitting, catalysts with both efficiency and durability to operate for a long time were needed.

Platinum, which is widely used as a catalyst, has high efficiency but corrodes easily in alkaline conditions, resulting in poor durability.

Analysis image of hydrogen generation active sites on ruthenium and carbon-supported catalysts.

The joint research team developed a ruthenium-based catalyst structure with high efficiency and strong durability across the entire pH range by selectively bonding ruthenium metal only to the ‘edges’ of the two-dimensional carbon material ‘graphene’.

By bonding ruthenium only to the edges of graphene, the basal plane of the graphene support is protected from damage, resulting in both high efficiency and durability.

When nitrogen is doped only at the ‘edge’ part of graphene, which supports the ruthenium metal, ruthenium bonds only along the nitrogen at the edges. This is because nitrogen has a strong tendency to accept electrons, while ruthenium tends to donate electrons.

First author Researcher Yang Ye-jin explained, “Using the edge with excellent bonding strength to metal, we developed a catalyst that shows stable performance in all aqueous environments.”

Co-first author Researcher Kim Jeong-won said, “When applying the developed catalyst to the water electrolysis system, it operated for 1,500 hours regardless of acidity, and the current density value indicating hydrogen evolution efficiency was higher than that of platinum.”

Professor Kim Geon-tae said, “We developed a catalyst that is inexpensive and shows excellent performance across all pH levels, including neutral. It will greatly help not only water electrolysis systems but also the commercialization of aqueous metal-CO₂ systems.”

This research was published online on July 6 in the international energy journal Nano Energy. The research was supported by Korea East-West Power, the Ministry of Science and ICT, and the National Research Foundation of Korea (NRF).

This content was produced with the assistance of AI translation services.