Structural Ni 0 -Ni δ+ Pair Sites for Highly Active Hydrogenation of Nitriles to Primary Amines.

Supported metal pair sites have sparked interest due to their tremendous potential as bifunctional catalysts. Here, we report the structural Ni 0 -Ni δ+ pair sites constructed in a well-defined nanocrystal phase of Ni 3 P. These Ni 0 -Ni δ+ pair sites exhibited a remarkable product formation rate of 123 mol BA /mol metal /h for the hydrogenation of benzonitrile (BN) to benzylamine (BA). The heterogeneity of surface Ni atoms over the Ni 3 P crystal created two types of metal centers, Ni 0 and Ni δ+ , with a specific spatial distance of 4-5 Å. The Ni 0 site acted as the center for H 2 activation, while the Ni δ+ site served as the adsorption and activation center for the C ≡ N group. The highly efficient cooperation effect of Ni 0 -Ni δ+ pair sites resulted in a TOF of 2915 h -1 in BN hydrogenation, which is 2.4 and 9.7 times higher than that over the mono-Ni 0 and -Ni δ+ sites, respectively.