Study On Intercalation Loading And Activity Of Nano Gold On Layered Clay

In this paper,two kinds of the layered structure of the clay-MMT and LDHs used as carrier to assembly prepare gold catalyst with liquid phase intercalation method.The sodium montmorillonite used as carrier and it was organically modified by chitosan that were fully loaded on the carrier and be intercalation in montmorillonite,then the gold sol were intercalating loaded on montmorillonite based on the complexation adsorption effect;When using LDHs as the carrier,the gold catalysts prepared by the way of the anion exchange to make chlorauric acid intercalate or adsorb onto LDHs.Detailed investigating the effect of intercalation and load condition of gold catalyst,the physical properties of the gold catalyst were characterized using XRD,TEM,XRF,XPS,TG-DSC,ect.Taking CO catalytic oxidation as model for reaction to evaluate the activity of two different types clay-supported gold catalysts.The results showed that:(1)Taking advantage of the exchangeability of cations among montmorillonite layers,and montmorillonite was modified by chitosan,this achieve good results with 5%mass fraction of cations to the carrier,pH=5 and continuous stirring 3h,then centrifugal washing for 30min in alkaline environment and montmorillonite modified by chitosan obtained.(2)Using montmorillonite organically modified by chitosan as carrier to load the gold sol,under the condition of pH=5 and ultrasonic oscillations to improve the dispersion effect of gold,2%mass fraction of Au/CS-MMT uniformly distributed gold catalysts with a particle size between 1?4 nm obtained.(3)Model reaction results show that the CO conversion rate was only 25%when use 2%Au/CS-MMT as catalyst at room temperature,however,taking it for 350?heat treatment,the conversion rate of CO at room temperature could be increased to 45%,and Au existed as Au0 and Au?+ on surface of catalysts.(4)The conversion rate of CO at room temperature was up to 95%with chlorauric acid intercalating in MgAl-NO3-LDHs to prepare intercalation supported catalyst,intercalation time 24h,10%mass fraction of Au contained in intercalator to the carrier,the reducing agent of NaBH4 ratio with gold 20:1.