University of Leeds scientists have claimed first fabrication of freestanding 2D gold with a sub‐nanometre thickness.
A team from the university’s Molecular and Nanoscale Physics Group synthesised the two-atom-thick gold nanosheet, which measures 0.47 nanometres thick, 1 million times thinner than a human fingernail.
Lab tests have shown that the gold is 10 times more efficient as a catalytic substrate than larger gold particles currently used in the industry.
Lead author of the research, Dr Sunjie Ye, said: "Not only does it open up the possibility that gold can be used more efficiently in existing technologies, it is providing a route which would allow material scientists to develop other 2D metals.
"This method could innovate nanomaterial manufacturing."
Gold has good conductivity and resists corrosion, making it useful in electronic components. While its expense limits its use, gains could be achieved from using ultra-thin gold due to its high surface-area-to-volume ratio.
This gives it potential applications for artificial enzymes, medical devices, electronic inks, point-of-care medical diagnostic tests, catalysts, water purification systems, transparent displays and bendable device screens.
Because of its green colour and frond-like shape, the researchers called it “gold nanoseaweed”. To synthesise the metal, they used chloroauric acid, an inorganic substance and an intermediate in the purification of gold metal, and methyl orange as a confining agent. They are now looking at methods to scale up the process.
Professor Stephen Evans, head of the research group, said: "Gold is a highly effective catalyst. Because the nanosheets are so thin, just about every gold atom plays a part in the catalysis. It means the process is highly efficient.
“Our data suggests industry could get the same effect from using a smaller amount of gold, and this has economic advantages when you are talking about a precious metal,” Professor Evans said.
Two-atom-thick gold could also open a route to other 2D materials that live up to commercial expectations more effectively than graphene has done so far.
“With graphene, people have thought that it could be good for electronics or for transparent coatings, or as carbon nanotubes that could make an elevator to take us into space because of its super strength,” he said.
"I think with 2D gold we have got some very definite ideas about where it could be used, particularly in catalytic reactions and enzymatic reactions. We know it will be more effective than existing technologies – so we have something that we believe people will be interested in developing with us."