Co₂free molten metal catalysts for hydrogen production improve efficiency by up to 36.3%

Korean researchers have developed advanced liquid metal catalysts incorporating selenium (SE) to increase the efficiency of turquoise hydrogen production.

Turquoise hydrogen is produced through methane (CH₄) pyrolysis, and produces solid carbon as a by-product, without releasing carbon (CO₂) while producing hydrogen.

A research team led by Dr. Seung-Ae-han of the Korea Institute of Chemical Technology (KRICT) has introduced selenium-doped molten metal catalysts (NIBI) to significantly improve methane pyrolysis efficiency. This technology exhibits high methane conversion rates and stable catalytic performance, paving the way for sustainable clean hydrogen production. This study has been published in Journal Applied Catalysis B: Environment and Energy.

Methane pyrolysis is an environmentally friendly hydrogen production method, which produces solid carbon instead of Co2 emissions. However, existing approaches face challenges, such as requiring very high temperatures and experiencing catalyst deactivation due to carbon deposition on solid catalysts.

To address these challenges, the researchers developed a ternary molten metal catalyst incorporating selenium.

Unlike traditional solid catalysts, molten metal catalysts remain in the liquid state, allowing efficient separation of carbon by-products, ensuring long-term stable reactions.

Selenium uptake reduces surface tension, maximizes the contact area between the reactant gas and the catalyst, leading to improved hydrogen production efficiency.

Selenium also reduces the activation energy required for methane conversion, thereby improving catalytic performance. In particular, selenium promotes surface exposure of nickel active sites, further increasing the efficiency of methane decomposition.

The addition of selenium reduces the surface tension of the NIBI-based catalyst by approximately 19%, reduces foaming, increases the catalyst contact area, and significantly improves reaction efficiency. The newly developed selenium-promoted three-way catalyst (NIBISE, Cubeads) achieved 36.3% and 20.5% improvement in methane conversion efficiency compared to conventional catalysts, respectively.

In particular, Nibise catalysts maintain stable performance for over 100 hours, showing exceptional long-term stability.

The researchers believe this groundbreaking technology could accelerate the commercialization of clean hydrogen production. Future research will focus on improving process efficiency and targeting commercial deployments through 2030.

“This research is expected to overcome the important limitations of existing turquoise hydrogen production technologies and contribute significantly to achieving carbon neutrality,” the researchers said.

“This technology is a co-innovation for carbon-free turquoise hydrogen production and will play a key role in its commercialization,” added Dr. Yeong-Kuk Lee, president of Krict.