Mass loss behavior in air and solid-state reaction mechanism of ammonium molybdate with LaHY were investigated by TG-DSC technique

and the physical structure

specific surface area

and surface acid sites by XRD

BET and NH3-TPD techniques. It showed that surface speicies of Mo arising from decomposition of (NH4)6Mo7O24·4H2O

over solid-state reaction of (NH4)6Mo7O24·4H2O with LaHY

allocates in LaHY molecular sieve cage as molybdenum-oxygen clusters to form a single-phase complex nMoOx·LaHY. The single-phase complex contributes to the lattice shrinkage

the reduced lattice parameter a0

and the decrease in specific surface area. The as-prepared nMoOx·LaHY possesses a slightly variation of weak acid center sites

an increase in medium strong acid center sites

a slightly decrease in strong acid center sites

and an increase in total acid sites

in comaprision with LaHY. The hydrodesulfulrization (HDS) performance of the single-phase complex nMoOx·LaHY was evaluated by using 0.6% (mass) dibenzothiophene(DBT)/decane as the representative reactants. The conversion of DBT in HDS process at 290℃ and 310℃ over nMoOx·LaHY catalyst with 5.0% (mass) of Mo loading

reached 56.38% and 88.79% under conditions of 4.0 MPa

20 h-1 of space velocity and 500:1 of H2/oil volumetric ratio

which increased 12 and 28 percentage than that of MoO3/Al2O3 with 20% (mass) of Mo loading

respectively. The nMoOx·LaHY catalyst exhibited higher activity for DBT HDS reaction.