ZSM-5 Microspheres Consisting of Nanocrystals for Preparing Highly Dispersed MoP Clusters with Good Activity in Phenanthrene Hydrogenation

Preparation of molybdenum phosphide with cluster size is important for enhancing its catalytic activity. Herein, ZSM-5 microspheres consisting of nanocrystals (ZSM-S-NA) were synthesized and used for the preparation of supported MoP catalysts (MoP/ZSM-5-NA). ZSM-5-NA exposes a large outer surface with abundant acidic sites, which benefit the strengthening metal-support interaction and have interconnected macronanoporous structure promoting the metal active component diffusion into the interior. Most of the MoP-active phases with cluster size (<1 nm) were highly dispersed on the surface of the MoP/ZSM-S-NA catalyst, whereas large MoP particles (5-10 nm) were formed on the SiO2 support because of the weak metal-support interaction. The intrinsic activity of MoP/ZSM-5-NA (r(obs) = 3.4 X 10(-4) mol-kg(-1).s(-1)) was higher than that of the SiO2-supported MoP catalyst (2.3 X 10(-4) mol.kg(-1)s(-1)) in the phenanthrene hydrogenation. Additionally, the calcined MoP/ZSM-5-NA sample was presulfided, followed by reduction, and the sulfur species incorporation into MoP phases led to the catalyst presenting high activity (4.1 X 10(-4) mol-kg(-1)-s(-1)).