Ni₂P Nanoparticles Supported on N, P Co-Doped Carbon as Catalyst for α-Alkylation of Arylacetonitriles with Alcohols

Abstract

The nickel phosphides have garnered increasing attention as an excellent catalytic site in the fields of electrocatalysis and hydrotreating, but their application in organic synthesis remains infrequent. In this study, ammonium phosphate and nickel chloride were employed as the doping sources for the first time to synthesize the Ni-based ZIF-8 precursor via the host−guest method. Subsequently, the precursor was pyrolyzed to obtain Ni 2 P nanoparticles (NPs) supported on N, P co-doped carbon. The composite materials exhibit elevated metal loading and effective dispersion due to the synergistic combination of phosphorus and nickel. Specifically, compared with Ni-NC, the optimal Ni 2 P-NCP-1 exhibits enhanced catalytic activity in the α-alkylation of arylacetonitriles with alcohols using KOH as the base. It shows a wide broad substrate scope at 140 °C for 12 h in n-octane using a hydrogen borrowing strategy. Through characterizations and mechanistic studies, it has been discovered that the introduction of P source not only provides more basic sites on carbon matrix but also leads to the formation of Ni 2 P NPs, which facilitates the catalytic efficiency by modifying the electronic structure of Ni. Compared with the metallic Ni species, the synergistic effect between Ni 2 P and acid-basic sites significantly influences the dehydrogenation of alcohols to generate Ni−H species. This study successfully achieves simultaneous phosphating of both the metal and support, and it also demonstrates that the N 2 P-NCP-1 catalyst has significant potential in the heterogeneous organic transformation field.