浸渍顺序对Pt-W/Al_2O_3催化剂物化性质和催化性能的影响  

Effect of Impregnation Sequence on the Physicochemical and Catalytic Properties of Pt-W/Al_2O_3 Catalyst

作　　者：杨建建[1] 郑仁垟[1] 李会峰[1] 李明丰[1] 

机构地区：[1]中国石化石油化工科学研究院,北京100083

出　　处：《石油学报（石油加工）》2017年第1期42-48,共7页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家重点基础研究发展计划项目(2012CB224802);中国石油化工股份有限公司科技开发项目(115059)资助

摘　　要：改变Pt、W前体盐的浸渍顺序,采用分步浸渍法制备了2个系列的Pt-W/Al_2O_3催化剂,并采用H_2-TPR、H_2脉冲化学吸附、XRD、XPS等技术,考察金属含量、金属盐浸渍顺序对催化剂物化性质及其催化甘油氢解性能的影响。结果表明,先浸渍(NH_4)6H_2W12O_40的Pt-W/Al_2O_3系列催化剂的H_2化学吸附量、催化甘油氢解的转化率和1,3-丙二醇选择性均高于先浸渍H_2PtCl_6·6H_2O的Pt-W/Al_2O_3系列催化剂的;且2个系列的Pt-W/Al_2O_3催化剂催化甘油氢解的转化率和1,3-丙二醇收率均随着WO_3含量的增加而先增加后减少,当WO_3质量分数为5%时,甘油转化率和1,3-丙二醇收率最高。这些变化规律主要归因于WO_3对Pt的分散作用、Pt-W的协同作用、合适的W负载量所形成的多钨酸物种提供了更多Br?nsted酸位等结构因素。2%Pt-5%W/Al_2O_3催化甘油氢解可获得59.6%的甘油转化率和43.3%的1,3-丙二醇选择性。By adjusting impregnation sequence,two series of Pt-W/Al_2O_3 catalysts were synthesized by using sequential impregnation.Characterization techniques of H_2-TPR,H_2 pulse chemisorption,XRD and XPS were used to investigate the effects of metal loading and impregnation sequence on the physicochemical and catalytic properties of the catalysts.The results showed that the H_2 uptake of Pt-W/Al_2O_3 catalysts synthesized by sequential impregnation of W-first,and the glycerol conversion and 1,3-propanediol selectivity of the catalytic glycerol hydrogenolysis were higher than those of the catalysts synthesized by sequential impregnation of Pt-first.With the increase of W loading,the glycerol conversion and 1,3-propanediol yield over both series of Pt-W/Al_2O_3 increased first then decreased,and the highest values occurred over the Pt-W/Al_2O_3 with W loading of 5%.These were attributed to the catalyst structure factors,including Pt dispersion by W species,Pt-W synergistic effect and more Br？nsted acid sites provided by an appropriate W loading.The glycerol conversion of 59.6% was obtained in glycerol hydrogenolysis over 2%Pt-5%W/Al_2O_3 catalyst with1,3-propanediol selectivity of 43.3%.

关 键 词：铂 氧化钨 甘油 氢解 1 3-丙二醇 

分 类 号：O643[理学—物理化学]