Pseudo-Technetium by Modern Alchemy

Despite showing a small application in the medical field, technetium significance has not been fully explored. Technetium has been generally considered unsafe for industrial applications owing to its radioactive nature in all isotope family. This has however not killed the interest of many researchers who still believe that it can support unique functionalities only if its electronic structure is explored and tailored. Presently, the concept of density of states engineering has been proposed for tuning chemical properties in alloys. The concept is based on the fact that most elements have their chemical and physical properties determined by their electronic states. However, regardless of the tremendous efforts made in the application of the density of states engineering concept, the creation of well-defined standards for evaluating its shape and template still remains a research area.

To this note, Dr. Wei Xie and Professor Michihisa Koyama from Kyushu University, INAMORI Frontier Research Center investigated the phase stability, electronic structure and catalytic activity of a newly designed pseudo- technetium material based on the density functional theory. Fundamentally, the density of states engineering concept was applied in designing the pseudo- technetium material.

Briefly, the authors commenced their research work by cross-examining the physical and chemical properties of the technetium materials. Next, they prepared and investigated four different binary alloys based on solid solution structures. This was aimed at exploring the feasibility of creating pseudo- technetium materials relying on the extended Kitagawa concept. The similarity in the chemical properties was obtained by adopting equal composition. As a result, the authors identified that bcc-Mo₈Ru₈ and hcp-Mo₈Ru₈ exhibited the most similar electronic structures to that of technetium. Subsequently, the possibility of synthesizing technetium materials was investigated using excess energy and entropy methods to find those can be synthesized at around 500 degree celcius. In addition, the catalytic properties of pseudo-technetium were explored. The authors found the material would be a good candidate for the N₂ dissociation catalyst, which is a key process for ammonia synthesis.

In summary, Professor Michihisa Koyama and Wei Xie successfully proposed a pseudo-technetium material based on density of states concept. To actualize their study, they evaluated the stability taking into consideration the effect of entropy to observe that after entropy correction stable technetium alloys were achieved thereby indicating the possibility of artificially synthesizing the chemical properties of technetium. They also proposed a possible application of the pseudo-technitium as ammonia synthesis catalyst. Therefore, the study provides essential information that will advance materials and catalysts design.  Their research work is currently published in journal, Chemical Science.