A Convenient Synthesis of Core-shell ZSM-5@MoO3 Catalyst for Enhanced Catalytic Properties in Methane Aromatization

摘要

A novel core-shell ZSM-5@MoO3 catalyst was successfully synthesized by the hydrothermal coating strategy,and its physicochemical properties and catalytic properties in methane aromatization were investigated using a physically-blended ZSM-5/MoO3 catalyst as a comparison.Multitechniques including XRD,SEM,TEM,EDS,N2 adsorption,ICP,IR and IG were employed to investigate the characteristics of methane aromatization reaction and the deactivation of carbon deposits.At the reaction temperature of 700℃ and a space velocity of 2400 mLg~(-1)h~(-1),methane conversion and aromatics selectivity of the core-shell ZSM-5@MoO3 catalyst were 11.3% and 88.1%,respectively,which were higher than those of the physically-blended ZSM-5/MoO3 catalyst by 3.1 % and 14.8%,respectively.The special reaction pathway of core(ZSM-5,acid sites)-shell(MoO3,Mo sites)and the relatively close proximity between MoO3 and ZSM-5 were mainly responsible for the excellent properties in the methane aromatization reaction.At the same time,the formation of the micro-mesoporous property accelerated the mass-transfer rate and inhibited the formation of carbonaceous deposition,greatly improving the stability of methane aromatization.Thanks to its core-shell structure,ZSM-5@MoO3 catalyst showed the excellent properties in methane aromatization.