Domestic researchers have developed a technology that enhances the production efficiency of turquoise hydrogen using a liquid metal catalyst with added selenium (Se). Turquoise hydrogen is hydrogen obtained from the thermal decomposition of methane, serving as an intermediate between fossil fuel-based hydrogen and renewable energy-based green hydrogen.
Han Seung-joo, a senior researcher at the Korea Research Institute of Chemical Technology (KRICT), noted on the 9th that his research team developed a technology that significantly improves methane thermal decomposition efficiency using a molten metal catalyst with added selenium. The research was published in December in the international journal 'Applied Catalysis B: Environmental and Energy.'
Methane thermal decomposition is an environmentally friendly technology for producing turquoise hydrogen, generating solid carbon as a byproduct and not emitting carbon dioxide, thus attracting attention. However, existing technologies require high temperatures or experience quick deactivation when solid catalysts are used due to carbon build-up on the catalyst surface.
To overcome the drawbacks of existing catalysts, the research team developed a three-component molten metal catalyst containing selenium that improves catalyst activity and bubble control performance. Instead of the existing solid catalyst, a molten metal catalyst that remains in a liquid state was used. The molten metal catalyst can physically separate the carbon produced during the methane thermal decomposition process, allowing for long-term stable reactions.
The addition of selenium reduced the surface tension of the catalyst and increased the surface activity. The reduction in catalyst surface tension maximized the contact area between the reaction gas and the catalyst surface, lengthening the residence time of reactants in the catalyst and increasing hydrogen productivity. It also reduced the activation energy required for the catalyst to operate, further enhancing surface activity.
As a result, the two selenium-containing three-component catalysts improved the conversion rate from methane to hydrogen by 36.3% and 20.5%, respectively, compared to the existing catalysts. Notably, the nickel-bismuth-selenium catalyst operated stably without performance degradation for over 100 hours.
The research team evaluated that the technology developed this time has significant potential to greatly accelerate the commercialization of clean hydrogen production. Through future follow-up studies, they plan to further improve process efficiency and increase the possibility of commercial application after 2030.
The research team stated, "This study is expected to contribute significantly to overcoming the limitations of existing turquoise hydrogen production technologies and realizing carbon neutrality." Lee Young-guk, the director of KRICT, noted, "This technology aimed at commercialization will establish itself as a key technology for producing turquoise hydrogen without carbon emissions."
Reference materials
Applied Catalysis B: Environmental and Energy (2024), DOI: https://doi.org/10.1016/j.apcatb.2024.125009
ACS Catalysis (2024), DOI: https://pubs.acs.org/doi/10.1021/acscatal.4c04480