Surface Single-Cluster Catalyst for N2-to-NH3 Thermal Conversion.

The ammonia synthesis from N2 is of vital importance, with imitating biological nitrogen fixation attracted much interest. Herein, we investigate the catalytic mechanisms of N2-to-NH3 thermal conversion on the singly dispersed bimetallic catalyst Rh1Co3/CoO(011), and find that the preferred pathway is an associative mechanism analogous to the biological process, in which alternating hydrogenations of the N2 occur, with H2 activation on both metal sites. We propose that the singly dispersed bimetallic M1An 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 N2-to-NH3 thermal conversion. The catalytic ability of M1An 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 M1An catalyst.