Highly dispersed Ni nanoparticles encapsulated in hollow mesoporous silica spheres as an efficient catalyst for quinoline hydrogenation

Abstract

With the aim of studying the effect of support structure and preparation method on the hydrogenation performance of Ni-based catalysts. Hollow mesoporous silica spheres (hw-mSiO2) containing tiny Ni nanoparticles highly dispersed on the inner surface ([email protected]2) were synthesized by using carbon sphere as template with four continuous procedures, containing Ni deposition, silica shell coating, calcination and reduction. As demonstrated by SEM and TEM, the hollow structure was successfully obtained after calcination and the active Ni species was highly dispersed inside the porous silica shell, which is much smaller than the Ni-based catalysts prepared by a conventional impregnation method using hw-mSiO2 (Ni/hw-mSiO2) or commercial SiO2 (Ni/mSiO2) as supports. TPR and H2-chemisorption results revealed the existence of strong metal-interaction and more hydrogenation sites in [email protected]2. Therefore, [email protected]2 catalyst achieved an excellent catalytic activity and stability in the selective hydrogenation of quinoline into 1–4-tetrahydroquinoline (py-THQ), due to the more dispersed Ni species, strong metal-support interaction and confinement effect of porous silica shell.