Can you reinvent the wheel? Scientists synthesized a new kind of graphene

The CU Boulder team, who published their findings in Nature Synthesis, detailed how they developed the material, which has long been theorized to contain unique electron-conducting, mechanical and optical properties.

"The whole audience, the whole field, is really excited that this long-standing problem, or this imaginary material, is finally getting realized," explained Yiming Hu (PhDChem'22), the lead author of the paper.

Creating graphyne is a "really old, long-standing question, but since the synthetic tools were limited, the interest went down," Hu continued. "We brought out the problem again and used a new tool to solve an old problem that is really important."

'People are very excited' 

That new tool came in the form of a process called alkyne metathesis — an organic reaction that cuts and reforms alkyne chemical bonds — as well as thermodynamics and kinetic control. With these processes, they were able to create graphyne, which has a similar conductivity to graphene but with control.

"There's a pretty big difference (between graphene and graphyne) but in a good way," said Wei Zhang, a professor of chemistry at CU Boulder whose work on reversible chemistry was integral to the creation of graphyne. "This could be the next generation wonder material. That's why people are very excited."

Now that the researchers have created graphyne, they want to investigate further and figure out how it could be produced on a mass scale, unlocking its potential in a similar fashion to graphene.

They also hope to learn more about how the material could be used for industry-wide applications, including in the production of lithium-ion batteries, for example. "We are really trying to explore this novel material from multiple dimensions, both experimentally and theoretically, from atomic-level to real devices," Zhang said. The team's hope is that they can bring down the production cost of graphyne dramatically, meaning it will have finished its journey from a long-theorized cousin of graphene to a full-on wonder material in its own right.

Abstract:
Most attempts to synthesize graphynes are limited to using irreversible coupling reactions, which often result in the formation of nanometre-scale materials that lack long-range order. Here the periodically sp–sp2-hybridized carbon allotrope, γ-graphyne, was synthesized in bulk via a reversible dynamic alkyne metathesis of alkynyl-substituted benzene monomers. The balance between kinetic and thermodynamic control was managed through the simultaneous use of two different hexa-alkynyl-substituted benzenes as the comonomers to yield crystalline γ-graphyne. Additionally, the ABC staggered interlayer stacking of the graphyne was revealed using powder X-ray and electron diffraction. Finally, the folding behaviour of the few-layer graphyne was also observed on exfoliation, and showed step edges within a single graphyne flake with a height of 9 nm.