Ulsan National Institute of Science and Technology (UNIST) researchers have a breakthrough in technology that efficiently converts liquid ammonia into hydrogen. Their findings have also attracted significant attention from academic research communities owing to its new analysis protocol, capable of finding optimal process environments.

In this study, the research team led by Professor Guntae Kim in the School of Energy and Chemical Engineering at UNIST, succeeded in producing hydrogen (H2) in large quantities with a purity of nearly 100 percent by decomposing liquid ammonia (NH3) using electricity. Additionally, according to the research team, the method consumed three times less power than hydrogen made by using electrolysis of water.

Their research paper has been published in the of Journal of Material Chemistry A.

Ammonia has emerged as an attractive potential hydrogen carrier due to its extremely high energy density, and ease of storage and handling. Moreover, noted the research team, the electrolysis of ammonia to produce nitrogen and hydrogen only requires an external voltage of 0.06 V theoretically, which is much lower than the energy needed for water electrolysis (1.23 V).

Ammonia decomposition for hydrogen release using electrical current observed by gas chromatography. Image Credit: Ulsan National Institute of Science and Technology, School of Energy and Chemical Engineering. Click image for the largest view.

In this study, the research team proposed a well-established procedure using in operando gas chromatography that enabled them to reliably compare and evaluate the new catalyst for ammonia oxidation. According to the research team, with the protocol, they could distinguish in detail the competitive oxidation reaction between the ammonia oxidation and oxygen evolution reactions with real-time monitoring.

With the use of flower-like electrodeposited platinum catalyst, the researchers efficiently produced hydrogen with less power consumption of 734 liters of H2 per KWH−1, which is significantly lower than that of the water-splitting process at 242 liters of H2 per KWH−1.

“The use of this rigorous protocol should help to evaluate the practical performances for ammonia oxidation, thus enabling the field to focus on viable pathways towards the practical electrochemical oxidation of ammonia to hydrogen,” noted the research team.

This study has been co-authored by Minzae Lee, Myung-gi Seo, Hyung-Ki Min, and Youngheon Choi from Lotte Chemical R&D Center, respectively.

Their work has also been featured on the inside back cover of Journal of Material Chemistry A, which was made available online in March 2021 ahead of final publication in May 2021. This research has been carried out with the support of Lotte Chemical, Ministry of Science and ICT (MSIT), and the National Research Foundation of Korea (NRF).

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This tech looks quite good, indeed. Eerily, the info has been out for months before the press release was published 10 days back in Korea. It would seem, although not stated, that others have tried replicating and perhaps the results are positive. That might be why the press release is finally out.

Ammonia is common, janitor’s grade is about 15%, household often 5% and a bit less for window cleaner. It stores in most modern containers. This just might be the hydrogen enthusiasts dream for solving the hydrogen storage conundrum.

However, while the voltage is low the amperage isn’t stated. Also the low cost leader for ammonia production uses natural gas for the raw material and needs heat to get the reaction going to form the ammonia. What’s not stated is the total energy input to get to the hydrogen fuel ready for use. Then there is the CO2 made during the process. And you really don’t want to spill pure ammonia on your skin or get it in your eyes.

Perhaps what is next could be a photocatalyst that splits water and forms NH3 with the free nitrogen in the air. No CO2 output, heat input, and it would keep a very long time without the hydrogen escaping and destroying the storage vessel.

This is one more very important step to open up the fuel and energy market. More, better and cheaper! It looks like something could be out there again!


Comments

2 Comments so far

  1. Matt Musson on August 17, 2021 7:33 AM

    It may take 1/3rd the electricity to split the hydrogen from ammonia, but water occurs naturally. Industrial ammonia is almost exclusively a manufactured item. So, if you don’t own a hog lagoon, you are expending energy making and transporting Ammonia that is later split. That negates the energy savings on the back end.

  2. Jagdish on August 18, 2021 1:28 AM

    Most of ammonia is produced with hydrogen as one of inputs. Power used is extra. The only benefit is transport of ammonia at lower pressure.
    A far better alternative would be carrying a metal hydride and water.

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