Nanographs are predicted to be a material for radically enhancing solar cells, fuel cells, LEDs, and so on. Typically, the synthesis of this material has been inaccurate and difficult to control. For the first time, researchers have found a simple way to gain precise control over the manufacture of nanographs. In doing so, they have clarified the clear chemical processes that preceded the production of the nanograph.
You’ve probably heard it graphene, one-atom-thick sheets of carbon molecules that seem to revolutionize technology. Graphene units are known as nanographs; they are adapted to specific functions and thus their manufacturing process is more difficult than generic graphene. Nanography is done by selectively removing hydrogen atoms from organic carbon and hydrogen molecules, a process called dehydrogenation.
“Dehydrogenation occurs on a metal surface, such as silver, gold, or copper, because it acts as a catalyst, a material that allows or accelerates the reaction,” said Akitoshi Shiotari, Assistant Professor in the Department of Advanced Materials Science. “However, this surface area is large compared to the target organic molecules. This causes difficulties in working with specific nanograph formations. We needed a better understanding of the catalytic process and a more precise way to control it. “
Shiotari and his team, having studied various ways of synthesizing nanographs, developed a method that provides the necessary precise control and is very effective. They used a specialized microscope called the Atomic Force Microscope (AFM), which measures the details of molecules with a needle-like nanoscopic probe. This probe can be used not only to detect certain characteristics of individual atoms, but also to manipulate them.
“We found that the AFM’s metal probe could break down carbon-hydrogen bonds in organic molecules,” Shiota said. “It could be very accurate because its point is so small, and it can break bonds without the need for thermal energy. That means we can now manufacture nanograph components in a more controlled way than ever before.”
To verify what they saw, the team repeated the process with several organic compounds, mainly two molecules with a very different structure called benzonoids and non-benzonoids. This demonstrates that the AFM probe is capable of extracting hydrogen atoms from different types of materials. This detail is important if this method is to be extended to a commercial means of production.
“I think this technique could be the ultimate way to create functional nanomolecules from the bottom up,” Shiotari said. “We can use an AFM to apply other stimuli to molecules, such as electrons, electronic fields, or to inject repulsive forces. It’s amazing to be able to see, control and manipulate structures that are on such a very small scale. “
Reference: “Manipulable Metal Catalyst for Nanographene Synthesis” by Akitoshi Shiotari *, Ikutaro Hamada, Takahiro Nakae, Shigeki Mori, Tetsuo Okujima, Hidemitsu Uno, Hiroshi Sakaguchi, Yuji Hamamoto, Yoshitada Morikawa and Yoshiaki Sugimoto, October 22, 2020 Dwarf Letters.
DOI: 10.1021 / acs.nanolett.0c03510
Funding: This work is JSPS KAKENHI JP16H00959, JP25110003, JP16H00967, JP15H06127, JP18H01807, JP18H03859 and JP18H05519. Akitoshi Shiotari has received support from ATI Research Grants 2017, Sumitomo Foundation and Shimadzu Science Foundation. Yoshiaki Sugimoto has acknowledged the support of the Toray Science Foundation.