Theoretical design of a technetium-like alloy and its catalytic properties

Abstract

Based on the concept of density of states (DOS) engineering, we theoretically designed a pseudo-Tc material (Mo–Ru alloy) and investigated its electronic structure, phase stability and catalytic activity by using density functional theory. Through comparing the DOS shape, peak distribution, and DOS area differences between Tc and the Mo–Ru alloy, we noticed that bcc-Mo₈Ru₈ and hcp-Mo₈Ru₈ had the most similar electronic structures to Tc. The excess energies after entropy correction of hcp-Mo₈Ru₈ and bcc-Mo₈Ru₈ are stable when the temperature is up to 765 and 745 K, respectively. These results provided the possibility of pseudo-Tc alloy (hcp-Mo₈Ru₈ and bcc-Mo₈Ru₈) synthesis. Finally, according to reaction coordinate analysis, the similar catalytic activity between hcp-Mo₈Ru₈ and Tc have been demonstrated in CO oxidation and N₂ dissociation. In N₂ dissociation, Tc has a suitable ratio of transition state (TS) barrier to reaction energy which make Tc an efficient catalyst for NH₃ synthesis, in addition to our designed pseudo-Tc (hcp-MoRu) because of the similar electronic structures. Our finding provides valuable insight into materials and catalyst design.