Catalyst promises cheap solar power

In a serendipitous discovery, researchers in Switzerland have found a way to revolutionise hydrogen production, which may have implications in solar energy storage.

A team from the Ecole Polytechnique Fédérale de Lausanne (EPFL) have discovered a molybdenum based catalyst produced at room temperature is an inexpensive alternative to platinum in hydrogen production.

Water is currently broken down into hydrogen and oxygen by electrolysis, but the platinum catalyst is expensive. EPFL scientists – led by Professor Xile Hu – discovered that amorphous molybdenum sulphides are an efficient catalyst that has the potential to lower the cost of hydrogen production.

“It’s a perfect illustration of the serendipity principle in fundamental research” said Hu. “Thanks to this unexpected result, we’ve revealed a unique phenomenon. But we don’t yet know why exactly why the catalysts are so efficient.”

“We were studying the electrochemistry of some coordination compounds, with the aim of finding catalysts for hydrogen production. We wanted to use tetrathiomolybdate as a control and thought it would not be active, so we could show that the target coordination compounds were better,” Hu told Laboratory News.

“It turned out that tetrathiomolybdate decomposed to form very active catalysts – we then spent a lot of time figuring out what these catalysts are.  These catalysts are simply better than our original targets, because they can be made from tetrathiomolybdate, which can be prepared easily or can be bought from a commercial source.”

 The catalyst is stable and compatible with acidic, neutral or basic conditions in water, and produce hydrogen faster that other catalysts of the same price.

The next stage of the research is to create a prototype that can help improve sunlight-driven hydrogen production. A better understanding of the observed phenomenon is required to optimise the catalysts.

“The next step is to use sunlight and water,” Hu told Laboratory News. “In that case, a wireless current is generated by sunlight. This direct photo-electrochemical approach of hydrogen production can serve as a storage method for solar energy. Because we have inexpensive and efficient hydrogen production catalysts, we can potentially lower the cost for such photo-electrochemical energy conversion devices. If the price of this solar-hydrogen becomes compatible with fossil fuel of the same energy content, we can replace the majority of fossil fuel in the energy sector, and diminish carbon dioxide emission.”