Platinum is used in catalytic converters to transform toxic fumes from a car's engine into more benign gases, to produce high octane gasoline, plastics and synthetic rubbers, and to fight the spread of cancerous tumors. But it's not cheap, which you know if you have ever shopped for an engagement ring knows.
In a new study, researchers from Duke University's Pratt School of Engineering used computational methods to identify dozens of platinum-group alloys that were previously unknown to science but could prove beneficial in a wide range of applications. If one of the compounds identified in the new study is comparable in performance but easier on the wallet, it would be a boon to many industries worldwide as well as the environment.
The identification of the new platinum-group compounds hinges on databases and algorithms. Using theories about how atoms interact to model chemical structures from the ground up, the engineers screened thousands of potential materials for high probabilities of stability. After nearly 40,000 calculations, the results identified 37 new binary alloys in the platinum-group metals, which include osmium, iridium ruthenium, rhodium, platinum and palladium.
Like theoretical physics or math, the issue becomes whether or not experimentalists can actually create what a numerical model produces.
But if they can be created, these metals prized for their catalytic properties, resistance to chemical corrosion and performance in high-temperature environments but high in prices because of their worldwide scarcity would become much more available.
"We're looking at the properties of 'expensium' and trying to develop 'cheapium,'" said Stefano Curtarolo, director of Duke's Center for Materials Genomics. "We're trying to automate the discovery of new materials and use our system to go further faster."
In addition to identifying unknown alloys, the study also provides detailed structural data on known materials. For example, there are indications that some may be structurally unstable at low temperatures. This isn't readily apparent because creating such materials is difficult, requiring high temperatures or pressures and very long equilibration processes.
"We hope providing a list of targets will help identify new compounds much faster and more cheaply," said Curtarolo. "Physically going through these potential combinations just to find the targets would take 200 to 300 graduate students five years. As it is, characterizing the targets we identified should keep the experimentalists busy for 20."