Design principles that will guide the search for more effective catalysts for fuel cells and metal-air batteries are reported online inNature Chemistry this week. Finding cheaper catalysts will enable the wider use of these clean-energy devices, which is currently hindered by the expense of the metals, such as platinum and palladium, which are currently used.
Yang Shao-Horn, Hubert Gasteiger and colleagues studied a range of oxide compounds called perovskites, and discovered that those containing manganese or nickel had the best performance. Using a molecular orbital approach, they concluded that there were two factors that determine catalyst performance: how many electrons are in a certain orbital and the extent of bonding between metal and oxygen atoms. With these rules as a guide, the search is now on for the best catalysts from these cost-effective materials, where the numbers of electrons and the bonding are ‘just right’.