Activated Carbon Supported Non-noble Bimetallic Ni-Based Catalysts for Nitrocyclohexane Hydrogenation to Cyclohexanone Oxime under Mild Conditions

Abstract

Activated carbon supported bimetallic Ni-based catalysts were prepared and applied in the selective hydrogenation of nitrocyclohexane (NCH) to cyclohexanone oxime (CHO). The characterization results show that the introduction of the metal promoter can inhibit Ni nanoparticle agglomeration and sintering. Among these bimetallic catalysts, the Cu-Ni/AC catalyst shows the best catalytic performance. The results indicate that introduction of a suitable amount of Cu can effectively promote Ni nanoparticle dispersion, decrease NiO reduction temperature, and facilitate metal Ni exposure. Density functional theory calculation results show that the CuNi (1 1 1) crystal surface possesses higher adsorption energies of H2 and NCH, lower adsorption energies of the active hydrogen (H*) and CHO, and lower reaction energy barriers of NCH hydrogenation to CHO than the Ni (1 1 1) crystal surface. Under the optimized conditions, 1%Cu-20%Ni/AC gives 99.6% NCH conversion and 87.8% high selectivity to CHO. Low-cost bimetallic Cu-Ni catalysts present potential application in economical commercial production of CHO from NCH.