Researchers at the Institute of Chemical Research of Catalonia (ICIQ) have found a new catalyst that ‘splits’ water molecules to obtain hydrogen and oxygen, needs very low voltages to work, and avoids the use of precious metals like iridium.
• Researchers at the Institute of Chemical Research of Catalonia (ICIQ) and Rovira and Virgili University (URV, both in Tarragona, Spain) presented their results in the prestigious scientific journal ‘Nature Chemistry’.
• The new catalyst features cobalt and tungsten, Earth-abundant materials that are way cheaper than current alternatives, based in precious metals like iridium.
• Hydrogen could become a clean and renewable fuel, it only produces water when you burn it.
Electrolysis, splitting the water molecule with electricity, is the cleanest way to obtain hydrogen, a clean and renewable fuel. Now, researchers at ICIQ and URV, led by Prof. José Ramón Galán-Mascarós, designed a new catalyst that reduces the cost of electrolytic hydrogen production. Catalysts reduce the amount of electricity needed to break the chemical bonds, speed up the reaction and minimize the energy waste.
‘Normally, hydrogen is obtained from using a cheap process called steam reforming. But this is not clean hydrogen, this process uses natural gas and produces carbon dioxide and other contaminants,’ explains Galán-Mascarós. ‘Breaking the water molecule is cleaner, but it’s not easy. We need to develop new cheap, efficient catalysts that allow us to obtain hydrogen at a competitive price,’ he says. To date, the best catalysts are based in iridium oxides, but iridium is a very expensive and scarce precious metal.
Chemists at ICIQ and URV discovered a compound made of cobalt and tungsten –technically called a polyoxometalate– which can catalyse water splitting better than iridium. ‘Polyoxometalates are nanometric molecular oxides that combine the best of two worlds, the great activity of oxides and the versatility of molecules,’ explains Marta Blasco-Ahicart, postdoctoral researcher at ICIQ and first author of the Nature Chemistry paper. ‘Our polyoxometalates are way cheaper than iridium and allow us to work in acidic media, the optimal media to generate oxygen that is normally a drawback for catalysts, which are usually consumed by the acid,’ clarifies Blasco-Ahicart.
Joaquín Soriano, co-author of the paper and currently a postdoctoral researcher at Trinity College in Dublin, explains that ‘our catalysts work especially well when we work with low voltages.’ ‘That may seem an issue’ –he explains– ‘but it is rather an advantage, it saves electricity and will allow us, soon, to obtain the energy required for water splitting from renewable sources like solar panels.’
More information can be found on the ICIQ website.