Is the Era of 'Green Hydrogen' Here? Key Technology for Extracting Hydrogen from Ammonia Developed

UNIST Professor Kim Geontae's Team Develops Green Hydrogen Production Technology with Significantly Reduced Power Consumption Compared to Water Electrolysis

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Research illustration of catalyst coating technology on green hydrogen production electrode (nickel-based).

[Asia Economy Yeongnam Reporting Headquarters Reporter Kim Yong-woo] A groundbreaking ‘green technology’ that converts liquid ammonia into hydrogen has emerged.

The technology to extract hydrogen from ammonia is considered a key technology to accelerate the green hydrogen era.

Green hydrogen refers to hydrogen produced without carbon dioxide emissions during the production process. Currently, more than 90% of hydrogen is synthesized by chemically converting (reforming) fossil fuels such as methane, a process that paradoxically emits carbon dioxide.

Following the development of an efficient technology to convert liquid ammonia into hydrogen, domestic researchers have also proposed a new analytical technique to identify optimal process conditions, attracting global attention.

The research team led by Professor Kim Geon-tae of the Department of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology (UNIST, President Lee Yong-hoon) succeeded in mass-producing green hydrogen (H2) with nearly 100% purity by electrolyzing liquid ammonia (NH₃).

According to evaluations using the analytical technique proposed by the research team, this method consumes three times less power than producing hydrogen through water electrolysis.

Among hydrogen transportation methods, ammonia synthesis is the most efficient. Synthesizing ammonia from hydrogen allows transporting 1.5 times more hydrogen with less loss during transport.

Another advantage is the ability to utilize existing liquefied ammonia transportation infrastructure. However, while the technology to synthesize hydrogen into ammonia is commercialized, the technology to extract hydrogen back from ammonia is still at an early stage.

In-operando Analysis Method for Ammonia Electrolysis Process.

The research team extracted hydrogen from liquid ammonia using a porous nickel foam (Ni foam) electrode. The nickel foam electrode surface has uniformly coated catalyst (platinum) particles applied by cyclic voltammetry, resulting in high efficiency.

When the synthesized electrode is immersed in liquid ammonia and current is applied, the liquid ammonia decomposes (electrolyzes), producing hydrogen.

The Faraday efficiency, an indicator of hydrogen purity, exceeded 90%, and the current density, representing the chemical reaction rate, was also high at over 500 mA cm-2.

Additionally, the team proposed a new protocol using gas chromatography to quantitatively analyze the amount of gas generated in real time, identifying efficient ammonia electrolysis process conditions (such as electrolyte acidity).

Under optimized operating conditions, 569 liters of hydrogen can be produced with 1 kWh of electricity. This is more than three times less power consumption compared to water electrolysis.

This demonstrates that green hydrogen can be produced using ammonia with less power and cost than water.

Comparison of the shapes of catalyst particles coated by the cyclic voltammetry method.

Yang Ye-jin, first author and integrated master’s and doctoral course researcher at UNIST’s Department of Energy Engineering, introduced, “We used an electrode fabrication method with excellent hydrogen production activity in the ammonia electrolysis environment.”

Yang said, “This electrode can be used in both oxidation and reduction reactions, which will greatly contribute to simplifying the ammonia electrolysis system and reducing construction costs.”

Co-first author Kim Jeong-won, also an integrated master’s and doctoral course researcher at UNIST’s Department of Energy Engineering, explained, “This study is significant in finding the optimal conditions for ammonia electrolysis operation and serves as a foundational study for the future commercialization of ammonia electrolysis.”

Professor Kim Geon-tae said, “If the high-efficiency electrode is applied to the ammonia electrolysis process, the commercialization of ammonia electrolysis hydrogen production technology will accelerate. This research also suggests the possibility of recycling ammonia and even waste ammonia into ‘CO2-free hydrogen,’ pioneering a new paradigm in renewable energy.”

This study involved Dr. Lee Min-jae, Seo Myung-gi, Min Hyung-gi, and Choi Young-heon from Lotte Chemical Basic Materials Research Institute as co-authors.

The research results were published online on March 27 in the international journal for energy and materials, Journal of Materials Chemistry A, selected as the inside front cover article and are scheduled for formal publication.

The research was supported by Lotte Chemical, the Ministry of Science and ICT, and the National Research Foundation of Korea (NRF).

From the front row, starting from the right (clockwise): Researcher Yang Ye-jin, Researcher Kim Jeong-won, Researcher Jo Hyo-i, Researcher Seong Ah-rim, Professor Kim Geon-tae.

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