Highly Stable Catalyst Helps Turn Water Into Fuel

Breaking the bonds between oxygen and hydrogen in water could be a key to the creation of hydrogen in a sustainable manner, but finding an economically viable technique for this has proved difficult. Researchers report a new hydrogen-generating catalyst that clears many of the obstacles – abundance, stability in acid conditions and efficiency.

In the journal Angewandte Chemie, researchers from the University of Illinois at Urbana-Champaign report on an electrocatalytic material made from mixing metal compounds with substance called perchloric acidElectrolyzers use electricity to break water molecules into oxygen and hydrogen. The most efficient of these devices use corrosive acids and electrode materials made of the metal compounds iridium oxide or ruthenium oxide. Iridium oxide is the more stable of the two, but iridium is one of the least abundant elements on Earth, so researchers are in search of an alternative material.

Much of the previous work was performed with electrolyzers made from just two elements – one metal and oxygen,” said Hong Yang, a co-author and professor of chemical and biomolecular engineering at Illinois. “In a recent study, we found if a compound has two metal elements – yttrium and ruthenium – and oxygen, the rate of water-splitting reaction increased.”

The researchers found that when they used perchloric acid as a catalyst and let the mixture react under heat, the physical nature of the yttrium ruthenate product changed. “The material became more porous and also had a new crystalline structure, different from all the solid catalysts we made before,” said Jaemin Kim, the lead author and a postdoctoral researcher. The new porous material the team developed – a pyrochlore oxide of yttrium ruthenate – can split water molecules at a higher rate than the current industry standard. “Because of the increased activity it promotes, a porous structure is highly desirable when it comes electrocatalysts,” Yang said. “These pores can be produced synthetically with nanometer-sized templates and substances for making ceramics; however, those can’t hold up under the high-temperature conditions needed for making high-quality solid catalysts.”

Source: https://news.illinois.edu/