Pt-Sn/Al2O3蜂窝催化剂催化氧化C6烃

Catalytic oxidation of C6 hydrocarbons on Pt-Sn/Al2O3 honeycomb catalysts

采用等体积分浸法制备Pt-Sn/Al2O3蜂窝催化剂(Pt含量仅为0.06wt%).运用X射线衍射(XRD)、透射电镜(TEM)等技术对催化剂理化性质进行表征,并选取4种代表性C6烃(苯、环己酮、环己烷和正己烷)对催化剂性能进行评价.活性评价试验中,Pt/Sn比为3/1催化效果最佳.此时4种C6烃转化率达到90%的温度(T(90))较Pt催化剂均降低约20℃,其原因在于Sn可将Pt分割为较小的团簇提高Pt分散度.寿命评价试验以环己烷为例同Pt-Sn蜂窝催化剂连续运行720h,催化活性无明显变化,其原因在于,Sn可有效抑制其粒径增长;Pt3Sn合金降低表面对C6烃的吸附,减少催化剂表面积炭.

The Pt-Sn/Al2O3 honeycomb catalysts were prepared by incipient wetness sequence impregnation procedure(the content of Pt is only 0.06wt%),which were characterized by XRD,TEM and so on.The performances of catalysts were evaluated by selecting four representative C6 hydrocarbons(benzene,cyclohexanone,cyclohexane and n-hexane).The optimal Pt/Sn ratio was 3/1(w/w)in evaluating the catalytic activities,where the T90 of four C6 hydrocarbons decreased by about 20℃ compared with the Pt catalyst.Sn improved dispersion of Pt by dividing Pt into smaller clusters.The conversion of cyclohexane over Pt/Sn=3/1catalyst displayed no significant change after 720h of continuous run,in that Sn inhibited size growth effectively and Pt3Sn alloy structure weakened the adsorption of C6 hydrocarbons to reduce surface coke deposition.