Professor Lin Xueping and researcher Shun Boyu from Linköping University in Sweden have successfully produced gold flakes with a thickness of only one atomic layer for the first time. This material, dubbed "Goldene," is said to endow gold with new properties, making it applicable in fields such as carbon dioxide conversion, hydrogen production, and the manufacture of high-value-added chemicals. The research findings were published in the journal "Nature Communications" on the 16th.
For a long time, scientists have been attempting to manufacture thin gold flakes with a single atomic thickness, but have repeatedly failed due to gold's tendency to clump together. This time, to create Goldene, researchers used a three-dimensional base material and embedded gold between layers of titanium and carbon.
In the production of the base material, researchers initially used a conductive ceramic called silicon carbide titanium, with silicon in thin layers. Their idea was to plate gold onto this material to create a contact point. However, when they exposed the components to high temperatures, the silicon layer inside the base material was replaced by gold.
Professor Lars Holtman, a professor of thin film physics at Linköping University, described this phenomenon as intercalation. What researchers found was titanium carbide gold. For years, they had been studying titanium carbide gold without knowing how the gold was peeled off or washed out.
By chance, researchers discovered a method that had been used in Japanese forging techniques for over 100 years. This method can etch away residual carbon and change the color of steel, using a reagent called "Murakami reagent."
Researchers experimented with different concentrations of Murakami reagent and different etching times. Etching had to be done in the dark because when the reagent was exposed to light, cyanide would be generated in the reaction, dissolving the gold. The final step was to stabilize the gold flakes. To prevent the exposed two-dimensional flakes from curling, they added a surfactant.
The gold flakes in the solution resembled cornflakes in milk. Researchers collected the gold using a "sieve" and examined it with an electron microscope, ultimately confirming the success of the experiment.
The new properties of Goldene stem from gold having two free bonds in two dimensions. Therefore, potential future applications may include carbon dioxide conversion, hydrogenation catalysis, selective production of high-value-added chemicals, hydrogen production, water purification, communications, and more.
