Synthesis of a Ni Phyllosilicate with Controlled Morphology for Deep Hydrogenation of Polycyclic Aromatic Hydrocarbons

Deep hydrogenation of polycyclic aromatic hydrocarbons is an important reaction in the petroleum industry. Sintering and coking of active metal nanoparticles are major reasons for deactivation. In this study, a Ni phyllosilicate with different morphologies was synthesized by a modified hydrothermal method and used in the hydrogenation of naphthalene. The physicochemical properties of the Ni phyllosilicate were carefully examined by various characterizations. The in situ exsolution of Ni nanoparticles inlaid into Ni phyllosilicate strengthens the interaction between nanoparticles and support, thereby maintaining the size of the Ni nanoparticles during the reaction. The surface Lewis acid sites of the Ni phyllosilicate are beneficial for the adsorption of aromatic substrates and favor the deep hydrogenation of polycyclic aromatic hydrocarbons under optimal reaction conditions. Besides, the pore size distribution of the Ni phyllosilicate may have a profound effect on its performance stability. The Ni phyllosilicate nanotube with large mesopores can be reused for at least seven times with a decalin yield of up to 92%, which is mainly attributed to the rapid desorption of hydrogenation product and less blocking of its active sites. The synergistic effect of the Lewis acid sites and pore size confers the Ni phyllosilicate nanotube with excellent catalytic performance and recycling stability in naphthalene hydrogenation.