Synopsis: More Catalysis with Less Platinum
Platinum’s stability at high temperatures and its ability to selectively catalyze molecules make it a popular metal in industrial applications, such as catalytic converters, fuel cells, and batteries. However, given the scarcity and cost of platinum (Pt), researchers have attempted to use less of it by creating Pt alloys with cheaper catalytically active elements. These alloys unfortunately can degrade at high temperatures, limiting their industrial use. Now, Henning Galinski and colleagues at the Swiss Federal Institute of Technology (ETH) in Zurich have isolated a ternary alloy of Pt that requires less of the metal than conventional Pt electrodes and is stable at temperatures up to 600 °C, making this new alloy a promising candidate for use in catalytic converters.
Galinski and his colleagues synthesized an alloy film out of Pt, yttrium (Y), and aluminum (Al), and then selectively dissolved out the Al, a process that causes the film to morph into a high-surface-area nanowire network resembling blood vessels. Based on experimental current-voltage curves, the researchers calculated the electrocatalytic activity of the metal matrix and found that it was 13 times higher than that of conventional Pt electrodes. According to the authors, the enhanced catalytic activity occurs because adding Y alters the alloy’s band structure.
This research is published in Physical Review Applied.
Correction (1 December 2014): An earlier version of the Synopsis incorrectly stated that rhodium is cheaper than platinum.