UNIST Develops High-Performance Oxygen Evolution Catalyst Based on Non-Precious Metals

[Asia Economy Yeongnam Reporting Headquarters, Reporter Hwang Du-yeol] A research team at UNIST has developed a high-performance oxygen evolution catalyst based on non-precious metals, bringing the realization of the hydrogen economy one step closer.

On the 21st, UNIST announced that Professor Kwon Young-guk’s team from the Department of Energy and Chemical Engineering developed a vanadium-nickel-iron-based catalyst incorporating nickel nitride.

This catalyst achieved a current density of 1 A/cm², which is twice the current density required for practical commercialization under alkaline conditions, at a low overpotential of 270 mV.

In stability tests, it was confirmed to operate stably without damage for 1,000 hours. Additionally, in an ultrapure water environment of an anion exchange membrane water electrolysis system, it demonstrated excellent performance with a current density of 685 mA/cm² at a total cell voltage of 1.85 V.

This value is approximately twice as high as that of precious metal catalyst-based anion exchange membrane water electrolysis performance (total cell voltage 1.85 V, current density 355 mA/cm²).

Water electrolysis technology is a representative technology for producing green hydrogen, a future energy carrier.

The key here is the price of the produced green hydrogen. The system developed to improve hydrogen economy compared to existing water electrolysis technologies is the anion exchange membrane water electrolysis system.

However, it remains at the research stage, and especially to enhance the durability of the BOP (Balance of Plant), water electrolysis technology using ultrapure water must be advanced.

In the case of ultrapure water electrolysis, additional energy is required compared to acidic or alkaline water electrolysis, making the development of suitable catalysts even more difficult.

The research team manufactured a high-performance oxygen evolution catalyst based on non-precious metals by growing nickel nitride on the surface of vanadium-nickel-iron oxyhydroxide through electroplating and nitriding processes.

Although nickel-iron oxyhydroxide is a representative oxygen evolution catalyst, it has the disadvantage of low electrical conductivity. To compensate for this, vanadium was doped and nickel nitride was grown on the surface to improve electrical conductivity and stabilize active sites, securing performance and long-term stability.

The enhanced electrical conductivity accelerated electron transfer rates at the interface between the catalyst and electrolyte, demonstrating excellent reaction rates. The developed catalyst showed outstanding performance not only in alkaline environments but also in an anion exchange membrane water electrolysis system flowing ultrapure water.

Professor Kwon Young-guk said, “Securing both performance and stability, the fundamental elements of catalysts, is essential for the commercialization of water electrolysis technology,” adding, “By thoroughly understanding the shortcomings of existing catalysts and striving to resolve them, we will contribute to realizing the hydrogen economy.”

Participating in this study (from left) Professor Kwon Young-guk, Researcher Kwon Seon-taek, Researcher Gong Tae-hoon, Researcher Pandiarajan Thangavel (PhD), and Researcher Lee Ho-jung are taking a group commemorative photo.

First author Dr. Pandiarajan Thangavel stated, “Existing nickel-iron-based catalysts have low electrical conductivity, and securing catalyst stability in water electrolysis environments was urgent,” adding, “We developed a high-performance, high-durability oxygen evolution catalyst based on non-precious metals by doping hetero elements and applying an additional nitriding process to compensate for these shortcomings.”

This research was published online on December 23, 2022, in the world-renowned journal in the energy and environmental science field, Advanced Energy Materials, and was selected as the cover paper, published on February 10.

The research was conducted with support from the Korea Research Foundation’s mid-career research program, the Ministry of Trade, Industry and Energy’s Energy Technology Development Project, and the National Research Council of Science & Technology’s Creative Convergence Research Project.

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