Preparation And Activity Study Of Montmorillonite Supported Gold Catalyst

A natural bentonite resource from Yanshan county in Yunnan province was used as raw materials to prepare Na-montmorillonite(Na-MMT)by purification and sodium modification in this paper.Na-MMT is modificated by alumina-pillared and organic respectively.Then using the modified montmorillonite as carrier to prepare the supported gold catalyst.The prepared catalyst samples were characterized by XRD,XRF,TEM and TG-DSC respectively.The supported gold catalyst activity of modificated Na-MMT was investigated by CO oxidation reaction.On this basis,first of all,using Al-PILM as carrier and Au(en)2C13 as precursor to prepare supported gold catalysts(Au/Al-PILM),and the influence of supported time,gold loadings,supported methods and content of reducing agent,reduction time and calcination temperature an the catalysts activity were discussed;Secondly,using chitosan organically modified Na-montmorillonite(CHI-Na-MMT)as carrier,gold sol as precursor which prepared in advance to get the supported gold catalyst(Au/CHI-Na-MMT),and the influence of supported methods and calcination temperature on the catalysts activity were discussed;Finally,Using Na-montmorillonite as carrier supported chitosan bound gold sol(Au-CHI)to prepare supported gold catalysts(CHI-Au/Na-MMT),and the influence of pH and calcination temperature on the catalysts activity were discussed.The results showed that:(1)Carrier modification has an important influence on the gold catalysts activity.The gold catalyst of aluminum-pillared montmorillonite as carrier(Au/Al-PILM)which exhibited a higher catalytic activity for the CO oxidation reaction than the Na-montmorillonite as carrier(Au/Na-MMT).(2)The gold catalyst(Au/Al-PILM)was prepared using Au(en)2Cl3 as precursor which was supported on aluminum-pillared montmorillonite.The proper preparation conditions as follows:for the catalyst lwt%Au/Al-PILM,55%conversion of CO was achieved at reaction temperature 50?,and with pH=10,supported time was 30min,content of reducing agent was NaBH4:Au=10:1,reduction time was 10min and at the calcination temperature 450? for 1h by common supported methods.(3)The gold catalyst(Au/CHI-Na-MMT)was prepared by chitosan modified Na-montmorillonite supported gold sol.The proper preparation conditions as follows:(4)for the catalyst 2wt%Au/CHI-Na-MMT,24%conversion of CO was achieved at reaction temperature 50?,and at the calcination temperature 200? for 1h by using ultrasonic supported methods.(5)The gold catalyst(Au-CHI/Na-MMT)was prepared by Na-montmorillonite supported chitosan modified gold sol(Au-CHI).The proper preparation conditions as follows:for the catalyst 2wt%Au-CHI/Na-MMT,54%conversion of CO was achieved at reaction temperature 50?,and with pH=5 and at the calcination temperature 200? for 1h.