Water-cleaning chemical made 'on-demand' with new group of catalysts

The team, from the Cardiff Catalyst Institute, Lehigh University and the Department of Energy's Oak Ridge National Laboratory in the USA, has developed a new group of catalysts that can produce hydrogen peroxide (H₂O₂) on-demand in a simple one-step process, opening up the possibility of manufacturing the chemical in some of the poorest, remote and disaster-stricken areas of the world.

Their results have been published in the journal Science.

"Using our new catalyst, we've created a method of efficiently producing H₂O₂ on-demand in a quick, one-step process," said co-author of the study Dr Simon Freakley from the Cardiff Catalysis Institute.

"Being able to produce H₂O₂ directly opens up a whole host of possibilities, most notably in the field of water purification where it would be indispensable to be able to produce the chemical on-site where safe and clean drinking water is at a premium."

Over four million tonnes of H₂O₂ are produced by industry each year, predominantly through a large, multi-step process, which requires highly concentrated solutions of H₂O₂ to be transported before dilution at the point of use. Current uses of H₂O₂ include paper bleaching, disinfecting and water treatment and in the chemical synthesis industry.

Though centralised systems adequately supply clean water to billions of households around the world, many people still do not have access to these large-scale water supplies and must therefore rely on decentralised systems for a safe source of water.

The team, led by Professor Graham Hutchings, has previously developed a state-of-the-art catalyst made from palladium and gold nanoparticles that helped to create H₂O₂ from hydrogen and oxygen.

Now the team have shown that gold can be replaced with five different readily available metals, including tin, zinc and cobalt, to form a much cheaper and more efficient group of catalysts for this specific reaction.

Co-author of the study Professor Graham Hutchings said: "Our new catalyst shows that it is possible to achieve equally high utilisation of hydrogen to form hydrogen peroxide by replacing the gold in the catalysts with cheap readily available metals, therefore significantly reducing costs.

"Rather than replace the current industrial process, we envisage this catalyst being used where low concentrations of hydrogen peroxide are required. For example, we could see our catalyst being used in decentralised water purification systems in which the speedy, on-demand production of hydrogen peroxide would be essential.

"We are already in discussions with industry to see how this catalyst can be developed further."