Scientists want to ‘trick’ gold into losing its greatest superpower

Gold’s greatest strength, its refusal to react with oxygen, is also its biggest limitation in industrial chemistry. Now that Tulane University researchers have discovered why gold resists tarnishing, they are exploring how to switch that protection off on demand.

The team found that surface atoms on gold rearrange themselves into patterns that block oxygen from reacting with the metal, slowing oxidation by a factor of a billion to a trillion. That same mechanism, however, makes gold a weak catalyst for reactions that specifically need it to interact with oxygen.

Gold-based catalysts already play a role in manufacturing vinyl acetate for plastics, and researchers are testing them to remove toxic carbon monoxide from car exhaust and to produce propylene oxide industrially. ‘If you can trick gold into dissociating oxygen, it can actually become a very effective catalyst for certain reactions,’ said Matthew Montemore, associate professor of Chemical Engineering at Tulane. ‘Our work suggests a new strategy for potentially doing that by preventing or reversing these surface rearrangements.’

Traditional methods for improving gold catalysts involve mixing gold with other metals or using tiny gold nanoparticles on oxide surfaces. Montemore and postdoctoral fellow Santu Biswas, whose findings were published in Physical Review Letters, suggest a different approach: controlling the physical shape of the gold surface itself to stop the protective atomic rearrangement from forming, making the metal more reactive exactly when needed for clean energy technologies.

Image: Wikimedia Commons/by Stevebidmead