Hiroshi Nishihara is a Professor, Research Institute for Science and Technology (RIST), Tokyo University of Science (TUS), Japan. He led an innovative research team that was the first to develop coordination nanosheets. After the results were published in the May 5, 2025 edition of Small, the groundbreaking discovery garnered major media attention. This stunning piece of work even won the coveted Front Cover of the issue.
The Ke researchers zeroed in on creating highly conductive coordination nanosheets in an ink-like format. This new synthesis route allows for these nanosheets to be applied as coatings on mechanical and thermal substrates. Furthermore, it opens the door for their application as chemical reactants. In the last ten years, it has been shown that coordinative transition metal ions, in particular nickel (Ni) ions coordinated to benzenehexathiol (BHT) can be efficiently synthesized as nanosheets. Up until now, a predictive approach for the targeted synthesis of these materials had not yet been established.
Nishihara stated what drove him to do this research, mentioning the difficulties encountered in obtaining accurate synthetic procedures. The research team validated that coordination nanosheets are highly effective in colloidal solutions. They developed a method for coating glassy carbon (GC) electrodes with nickel dithiolene (NiDT) and NiBHT. These exemplary results proved that NiDT-coated GC electrodes had an exciting potential for catalyzing the HER.
Miyu Ito, a current Master’s student at TUS, played a key role in advancing the research. She worked intimately with project researchers Dr. Naoya Fukui, Dr. Kenji Takada, and Dr. Hiroaki Maeda, a lecturer at TUS. They achieved an excellent result through the transmetallation reaction of NiBHT film with Cu2+ metal ions. This process led to the formation of electrochemically active NiCu2BHT nanosheets. Their high crystallinity and electrical conductivity endow these heterometallic nanosheets with promising applications in versatile electronics.
“When Ni ions are used in the two-phase interfacial reaction, porous nickelladithiolene (NiDT) and non-porous NiBHT structures are obtained. However, a rational method for selectively synthesizing them has not been fully established until now,” – Prof. Nishihara
Nishihara emphasized the significance of their work by stating, “The first ink made from coordination nanosheets has made it possible to mass-produce them using printing technology and to apply them directly to devices, marking a major step forward in their practical use as next-generation flexible electronic devices, hydrogen production catalysts, and sensor materials.”
The team’s advancements in synthesizing NiCu2BHT highlight the superiority of the structure and physical properties inherent in heterometallic coordination nanosheets.
“NiCu2BHT has high crystallinity and electrical conductivity and can be utilized in diverse electronic applications. This shows the superiority of the structure and physical properties of heterometallic coordination nanosheets with a defined structure,” – Prof. Nishihara