Introducing 'goldene': this gilded relative of graphene boasts a single-atom thickness.

To fabricate goldene, the researchers from Linköping University initiated the process with a substance containing silicon monolayers nestled between layers of titanium carbide. Upon adding gold atop this composite, it infiltrated the structure, displacing the silicon to establish a confined, single-atom-thick gold layer (refer to 'Gold mining'). Subsequently, they dissolved the titanium carbide using Murukami's reagent, a solution comprising alkaline potassium ferricyanide, liberating standalone goldene sheets. These sheets spanned up to 100 nanometers in width, approximately 400 times thinner than the most delicate commercially available gold leaf, as estimated by Hultman.

Remarkably, the etching technique relied on a century-old recipe employed by Japanese craftsmen to embellish ironwork, a fact that fascinates Hultman. Additionally, the researchers introduced surfactant molecules to create a protective barrier around goldene, preventing sheets from adhering to each other in the surrounding liquid.

The Linköping team envisions goldene's potential in domains where gold nanoparticles have already displayed promise. The surface of gold nanoparticles can induce waves in the sea of electrons, effectively concentrating and channeling energy. This light-responsive behavior has been leveraged in gold photocatalysts for applications like water splitting to yield hydrogen. Hultman suggests that goldene could expand possibilities in such fields, pending a thorough investigation of its properties.

Graham Hutchings, a chemist at the University of Cardiff, UK, who specializes in gold catalysts, finds the research intriguing. However, he expresses concern about potential iron contamination from Murukami's reagent hindering goldene's viability as a catalyst. "Residual iron contamination could pose challenges in practical applications," he remarks.

Presently, the Linköping researchers are exploring improved techniques to isolate goldene from the production solution and to cultivate larger flakes of the material. Furthermore, they are investigating whether their methodology can be adapted to produce monolayers of other catalytic metals like iridium, platinum, and palladium.