Study On Preparation Of Modified Ba-MgO Supported Ru Catalyst And Interaction Among Ru,Ba And MgO

This article is focused on the doping modification of nano-magnesia and investigate the metal support interaction between Ru,Ba and MgO,a series of doped nano-magnesia supported Ru-based catalysts for ammonia synthesis were prepared by chemical precipitation-strong electrical adsorption（SEA）method with the aid of ultrasonic wave and impregnation method,respectively.The modified samples were characterized by X-ray diffraction（XRD）,Field emission scanning electron microscopy（FE-SEM）,Energy dispersive X-ray（EDS）,N₂physical adsorption,Temperature programmed desorption（TPD）,Thermogravimetry Analysis（TG）,X-ray photoelectron spectroscopy（XPS）and High resolution transmission electron microscopy（HR-TEM）,etc.The main research contents and results were as follows:1.The composition and properties of the supports were changed with dope of Si,and Si main existed with the form of Mg₂Si O₄.When the content of Si was 10%,Ba was 1%（Mg:Ba=10:1）,the pH value of precipitation solution was 10.5 and the calcination temperature was 600℃,the activity of Ru/Ba-MgO catalyst was 16.8%（volume percentage）under the reaction condition of 400℃,10.0 MPa and 10000 h^-1.2.PVA was added to modified with the prepare of Ba-MgO support,the Ba content of Ba-MgO support and the activity of Ru catalyst were increased with the appropriate added of PVA.When 5%PVA was added,the activity of Ru/Ba-MgO catalyst was 17.1%（volume percentage）under the reaction condition of 400℃,10.0MPa and 10000 h^-1.3.HA was added to modified with the prepare of Ba-MgO support,the Ba content,BET specific surface area,pore volume and pore size of Ba-MgO support and the activity of Ru catalyst were increased with the added of HA.When 2%HA was added,the activity of Ru/Ba-MgO catalyst was 18.5%（volume percentage）under the reaction condition of 400℃,10.0 MPa and 10000 h^-1.4.Compared with the Ru catalyst prepared with Ba-MgO support modified with PVA,the Ru catalyst prepared with Ba-MgO support modified with HA contain more LT-BaCO₃,and more easily to be reduced.Furthermore,the more the LT-BaCO₃relative content of Ru/Ba-MgO,the catalytic activity the better.