Researchers from South Korea’s Chung-Ang University have developed a newcatalyst for producing green hydrogen from water electrolysis, according to a study published in the Journal of Energy Chemistry. The researchers claim that this catalyst is more efficient, stable, and affordable than conventional iridium-based catalysts.

REFRESHER- Catalyst? Electrolysis? Water electrolysis is the process in green hydrogen production which uses electricity to split water into hydrogen and oxygen molecules. One of the challenges in water electrolysis is the oxygen evolution reaction (OER), which requires a lot of energy and a durable catalyst to operate in acidic solutions. The most common catalysts for the process currently are platinum and iridium which are too costly and scarce.

The hunt for a better catalyst: Researchers have been trying to identify new catalysts for hydrogen production to replace their conventional alternatives. Egypt’s American University in Cairo is also trying to substitute expensive, difficult-to-source platinum for other, more readily available ‘transition’ metals.

Enter the new catalyst: The catalyst is made of single-atom zinc-doped ruthenium oxide with enriched oxygen vacancies, which enhances the stability and activity of the material. The researchers developed a new method to create the catalyst by thermally decomposing a metal-organic framework (MOF) precursor. The MOF — composed of zinc and ruthenium ions — was first loaded with different amounts of ruthenium ions and then annealed (a process of heating metals then allowing them to slowly cool) at low temperatures in the air.

How does it work? The researchers tested their catalyst in a proton exchange membrane (PEM) water electrolyzer. The catalyst showed impressive performance in the OER under acidic conditions. They found that their catalyst outperformed the commercial ruthenium oxide catalyst in terms of activity, stability, and overpotential.

So what makes it special? The researchers explained that their catalyst can overcome the drawbacks of conventional ruthenium oxide catalysts, which suffer from poor durability and high overpotential in acidic conditions. This makes the catalyst more resistant to corrosion and overoxidation, which are common problems in acidic OER. The catalyst lowers the energy barrier for the reaction, making it faster and more efficient. The catalyst also showed no significant degradation after 43 hours of operation, while the commercial catalyst failed after 7.4 hours.

Looking forward: The researchers concluded that their work provides a promising way to design high-performance OER catalysts for acidic water splitting, which could pave the way for sustainable hydrogen production from renewable energy sources.

Tags: