Gold may stay shiny because some of its surface atoms reorganize into structures that block oxygen reactions.
Gold has been valued for millennia because it keeps its shine, but new research from Tulane University suggests that this durability is not explained by chemistry alone.
In a study published in Physical Review Letters, Tulane researchers found that atoms on some gold surfaces can shift into protective arrangements that greatly reduce reactions with oxygen.
That finding helps explain why gold jewelry and other gold objects can stay bright for centuries. It may also help scientists design better gold-based catalysts for industrial chemistry and energy-related uses.
Atoms form a hidden shield
“People have generally thought gold doesn’t tarnish simply because it doesn’t interact strongly with oxygen,” said Matthew Montemore, associate professor in Chemical Engineering in Tulane’s School of Science and Engineering. “What we show is that for two of the most common gold surface types, the surface atoms actually rearrange themselves in a way that makes the gold much more resistant to oxidation.”
Montemore and coauthor Santu Biswas, a postdoctoral fellow in Tulane’s Department of Chemical & Biomolecular Engineering, used computer simulations to study how atoms and electrons behave when oxygen molecules meet two common gold surface structures. Their results showed that oxygen molecules would split apart and react with gold far more easily if the surface atoms did not reorganize.
With the rearranged surfaces in place, reactions with oxygen were reduced by a factor of a billion to a trillion. In effect, the shifted atoms create a protective barrier at the atomic scale, helping gold remain shiny over extremely long periods.
Gold’s resistance limits catalysts
The results offer a new explanation for gold’s famous resistance to tarnish, while also pointing to possible improvements in catalysis.
Gold-based catalysts, which help chemical reactions happen faster, are already used in some industrial oxidation reactions. But the same resistance that makes gold useful for jewelry and electronics can also make it less effective in chemical manufacturing and energy applications because it does not easily split oxygen molecules.
Catalysts that combine gold and palladium are used to produce vinyl acetate, a chemical used to make many plastics and other materials. Gold catalysts are also being studied for applications such as removing carbon monoxide from vehicle exhaust and producing propylene oxide, an important industrial chemical.
Surface design could unlock reactivity
“If you can trick gold into dissociating oxygen, it can actually become a very effective catalyst for certain reactions,” Montemore said. “Our work suggests a new strategy for potentially doing that by preventing or reversing these surface rearrangements.”
Past efforts to improve gold catalysts have often focused on mixing gold with other metals or placing tiny gold nanoparticles on oxide surfaces. The new work suggests that changing the geometry of the gold surface itself could offer another way to make gold more reactive.
Reference: “Role of Reconstruction in the Inertness of Gold toward Oxygen” by Santu Biswas and Matthew M. Montemore, 21 May 2026, Physical Review Letters.
DOI: 10.1103/g3bc-t1qv
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