Scientists have made a major breakthrough in creating a more sustainable and cost-effective method for producing hydrogen, a crucial component in the push for renewable energy sources.

The current method is expensive and unsustainable

Traditional methods of producing industrial hydrogen rely on using platinum metal as a catalyst to separate hydrogen molecules from oxygen atoms in water through electrolysis. However, platinum is both expensive and rare, making it an unattractive option in a world increasingly focused on environmentally friendly energy sources.

Inspiration from nature

Instead, researchers at the University of Illinois Urbana Champaign have turned to nature for inspiration. The team has been studying the way that nature’s nickel-iron hydrogenase enzyme produces hydrogen using earth-abundant metals in its core.

The study was led by chemistry professor Liviu Mirica together with graduate student Sagnik Chakrabarti. “The nickel at the core of the natural enzyme produces hydrogen by reducing protons in water. During the catalytic process, the nickel center goes through paramagnetic intermediates, meaning that the intermediates have an unpaired electron – which makes them extremely short-lived,” – said Chakrabarti.

Synthetic chemists have made nickel compounds that produce hydrogen for over a decade, Mirica said. While some of these compounds are very efficient at producing hydrogen, most operate via intermediates that are not paramagnetic.

“Researchers are trying to mimic exactly what nature does because it is efficient, and maximizing efficiency is a key challenge to overcome when engineering energy sources,” Mirica said. “Being able to reproduce the paramagnetic intermediate steps that occur in the natural enzyme is what our group is trying to achieve – to increase efficiency and mimic nature.”

The nerdy details – the key difference from other catalysts

The team has created an organic molecule called a ligand that contains electron-donating atoms like nitrogen and sulfur. This ligand can hold the nickel in place and support the two relevant paramagnetic states that produce hydrogen, just like the natural enzyme. The key difference from other catalysts is that the molecule also contains a carbon-hydrogen bond near the nickel centre that is broken and re-formed during catalysis, stabilizing the intermediates and making the process much more efficient.

The new solution may be a real breakthrough

The breakthrough could be a game-changer in the production of industrial hydrogen. Synthetic chemists have been creating nickel compounds that produce hydrogen for over a decade, but most operate via intermediates that are not paramagnetic. The team at the University of Illinois has successfully united ideas from two fields of inorganic chemistry – bioinorganic and organometallic chemistry – to make nickel complexes that behave similarly to the active site of nature’s most complicated enzymes.

Several unusual enzymes have been found that feature metal-carbon bonds in their active sites. The researchers believe this breakthrough could lead to further insights into how nature performs chemistry with small molecules like hydrogen. The design principles used in synthetic complexes could unlock new ways of producing hydrogen more sustainably and cost-effectively.

Growing demand for hydrogen

This breakthrough is particularly timely, given the growing demand for hydrogen as a fuel source. Many car manufacturers are turning to hydrogen fuel cells as a more sustainable and environmentally friendly alternative to traditional combustion engines. In addition, hydrogen is used extensively in manufacturing chemicals, such as ammonia and methanol, and is essential in refining crude oil.

The traditional method of producing industrial hydrogen using platinum as a catalyst is expensive and unsustainable. However, this breakthrough could provide a more cost-effective and sustainable alternative, using earth-abundant metals instead of rare and costly platinum. The team at the University of Illinois has shown that by studying nature, we can find new ways of producing energy that is both sustainable and efficient.

This breakthrough could have far-reaching implications for the energy sector, providing a more sustainable and cost-effective way of producing hydrogen, a key component in the drive towards renewable energy sources. It’s clear that nature still has much to teach us.