Surface Single-Cluster Catalyst for N 2 -to-NH 3 Thermal Conversion.

The ammonia synthesis from N ₂ is of vital importance, with imitating biological nitrogen fixation attracted much interest. Herein, we investigate the catalytic mechanisms of N ₂ -to-NH ₃ thermal conversion on the singly dispersed bimetallic catalyst Rh ₁ Co ₃ /CoO(011), and find that the preferred pathway is an associative mechanism analogous to the biological process, in which alternating hydrogenations of the N ₂ occur, with H ₂ activation on both metal sites. We propose that the singly dispersed bimetallic M ₁ A _n 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 ₂ -to-NH ₃ thermal conversion. The catalytic ability of M ₁ A _n 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 ₁ A _n catalyst.