2024/03/06
Keio University
A research group including Kazuya Terasaka (then a second-year master's student) and Takumi Ichikawa (second-year master's student) from the Graduate School of Science and Technology at Keio University; Masahiro Shibuta (a researcher at the time, now an associate professor at Osaka Metropolitan University) from the Keio Institute of Pure and Applied Sciences (KiPAS); and Associate Professor Miho Hatanaka and Professor Atsushi Nakajima from the Faculty of Science and Technology at Keio University, has successfully demonstrated that a nanostructure encapsulating a tungsten metal atom within a silicon cage acts as a superatom similar to an alkaline earth metal atom, in concert with its spherical structure. They have diversified the library of superatoms and, for the first time, immobilized an alkaline earth metal atom-like superatom on a solid surface.
The development of functional substrates using new nanostructures is crucial for overcoming energy and environmental challenges by further enhancing the efficiency of chemical and energy conversion processes. Among nanostructures composed of a few to several tens of atoms, some exhibit electronic states similar to those of individual atoms and are known as nanocluster superatoms. It was previously known that encapsulating different elements within them significantly alters their reactivity. However, challenges remained: it is difficult to produce nanocluster superatoms with a single, defined number of atoms and composition. Furthermore, on substrate surfaces, controlling the charge state is not easy due to surface properties and structural distortions that can deform the nanocluster superatoms, and the types of superatoms were limited to those involved in single-electron transfers.
This research group has established a technology for synthesizing large quantities of pure superatoms with perfectly controlled numbers of atoms and compositions, and for immobilizing them on a substrate in a non-destructive and stable manner. Furthermore, by utilizing nanostructures based on superatoms with a substituted central metal atom, they also discovered that when the central metal atom is changed, its geometric structure acts in concert to donate two electrons and stabilize on the substrate. These results are expected to lead to the creation of functional composite nanostructures that will enable next-generation chemical and energy conversions through the diversification of superatoms.
The results of this research were published in the American Chemical Society's journal, "Journal of the American Chemical Society," on March 1, 2024 (U.S. time).
Please see below for the full press release.