Surface Single-Cluster Catalyst for N<sub>2</sub>‑to-NH<sub>3</sub> Thermal Conversion

The ammonia synthesis from N<sub>2</sub> is of vital importance, with imitating biological nitrogen fixation attracted much interest. Herein, we investigate the catalytic mechanisms of N<sub>2</sub>-to-NH<sub>3</sub> thermal conversion on the singly dispersed bimetallic catalyst Rh<sub>1</sub>Co<sub>3</sub>/CoO­(011), and find that the preferred pathway is an associative mechanism analogous to the biological process, in which alternating hydrogenations of the N<sub>2</sub> occur, with H<sub>2</sub> activation on both metal sites. We propose that the singly dispersed bimetallic M<sub>1</sub>A<sub><i>n</i></sub> catalyst, in which the doped metal atom M substitutes an oxygen atom on the oxide surface of metal A, serves as a new surface single-cluster catalyst (SCC) design platform for the biomimetic N<sub>2</sub>-to-NH<sub>3</sub> thermal conversion. The catalytic ability of M<sub>1</sub>A<sub><i>n</i></sub> catalyst is attributed to both the charge buffer capacity of doped metal M and the complementary role of synergic metal A in catalysis. Our work provides insights and guidelines for further optimizing the M<sub>1</sub>A<sub><i>n</i></sub> catalyst.