Effect of Order of Impregnation of Mo and Ni on the Hydrodenitrogenation Activity of NiO-MoO3/AlMCM-41 Catalyst

The influence of order of the impregnation of NiO and MoO3 on the structure and catalytic behavior of H-AlMCM-41 supported Ni−Mo catalysts for hydrodenitrogenation (HDN) has been investigated. These catalysts were well characterized by TEM, XRD, N2 adsorption−desorption, XPS, and FT-IR spectra of CO adsorption and tested for hydrodenitrogenation (HDN) of o-toluidine and cyclohexylamine. It was found that the catalyst prepared by sequential impregnation of NiO and MoO3 was more active than the catalyst prepared by coimpregnation. Among the sequentially impregnated catalysts, the catalyst in which NiO deposited first followed by MoO3 shows high HDN activity. TEM, FT-IR spectra of CO adsorption, and estimation of total sulfur of sulfide catalyst results clearly show that the NiO and MoO3 are well dispersed over H-AlMCM-41 on reverse order impregnated catalyst. The very low activity of coimpregnated catalyst is attributed to poor dispersion of metal oxides as well as due to the formation of stable stoichiometric oxide and aggregates of metal particle over the support surface.