- Researchers have devised a method for converting carbon into various forms such as graphene or nanodiamonds.
- The technique uses a “flash” of electricity to heat the carbon into a final form.
- The new Flash Joule Heating process can help produce new forms in bulk.
Producing Nanodiamonds in a flash
Rice University researchers have found a method for directly converting carbon from a range of sources into usable forms such as graphene or diamond. A “flash” of electricity is used to heat the carbon, transforming it into a final form specified by the length of the flash.
The technique is known as flash joule heating (FJH), and the researchers detailed it for the first time in January 2020. A current is run through carbon-containing materials, heating them to about 2,727 °C (4,940 °F), converting the carbon into pure, turbostratic graphene flakes.
The method has now been improved by the researchers so that it may be used to manufacture different materials. The original flashes lasted 10 milliseconds, but the researchers discovered that by varying the length between 10 and 500 milliseconds, they could also direct the carbon into different shapes. Nanodiamond is one example, as is “concentric carbon,” in which carbon atoms create a shell around a nanodiamond core.
Organic fluorine compounds and precursors are now introduced to the mix at the start of the process to help it along. Previous research has shown that fluorine helps carbon atoms cling together more tightly, allowing nanodiamonds to be created under softer circumstances – typically, extremely high pressures are required.
Flash Joule Heating to be used for mass production
According to the scientists, the novel FJH technique can assist create these new forms in mass, which has historically been difficult. Fluorinated nanodiamonds, for example, are more helpful in electrical components such as semiconductors but require a different doping procedure.
“In industry, there has been a long-standing use for small diamonds in cutting tools and as electrical insulators,” says James Tour, lead researcher on the study. “The fluorinated version here provides a route to modifications of these structures. And there is a large demand for graphene, while the fluorinated family is newly produced here in bulk form. The concentric-shelled structures have been used as lubricant additives, and this flash method might provide an inexpensive and fast route to these formations.”
The team says that the next steps are to experiment with using other additives such as boron, phosphorus, and nitrogen.