How can gold always keep its glitter? Researchers uncover atomic secret behind Gold’s lasting shine

The study, published in Physical Review Letters, found that atoms on certain gold surfaces spontaneously rearrange themselves into protective patterns that sharply reduce reactions with oxygen.

The discovery sheds new light on why gold jewelry and artifacts can retain their shine for centuries and may also help scientists develop more efficient gold-based catalysts for industrial and energy applications.

“People have generally thought gold doesn’t tarnish simply because it doesn’t interact strongly with oxygen,” said Matthew Montemore, associate professor of chemical engineering at 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.”

Using advanced computer simulations, Montemore and co-author Santu Biswas examined how oxygen molecules interact with two widely occurring gold surface structures. The researchers discovered that without these atomic rearrangements, oxygen molecules could split apart and react with gold far more easily.

Instead, the self-organized surface patterns suppress oxygen reactions by factors ranging from a billion to a trillion, effectively creating an atomic-scale protective shield that allows gold to remain untarnished over long periods.

Beyond explaining gold’s enduring luster, the findings could have important implications for catalysis — the process of speeding up chemical reactions in industrial manufacturing and energy systems.

Gold-based catalysts are already used in several industrial oxidation processes. However, gold’s resistance to breaking apart oxygen molecules, while beneficial for jewelry and electronics, can also reduce its effectiveness in certain chemical reactions.

Gold-palladium catalysts, for example, are used in the production of vinyl acetate, a key ingredient in plastics and other materials. Scientists are also investigating gold catalysts for reducing carbon monoxide emissions in vehicle exhaust systems and producing propylene oxide, a widely used industrial chemical.

“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.”

Researchers have traditionally attempted to enhance gold catalysts by mixing gold with other metals or using nanoscale gold particles on oxide surfaces. The new study suggests that manipulating surface geometry itself could provide another pathway for improving gold’s catalytic performance.