文献汇报.pptx

1 J.Zecevic,G.Vanbutsele,K.P.de Jong,J.A.Martens,Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons,Nature,528(2015)245-248.1双功能催化剂上纳米尺度的接触用于烃类选择性转化汇报人：汇报日期：1.引言2双功能的烃类裂解催化剂包含金属活性位和酸性位；（intimacy criterion)由于合成和表征手段有限，金属和酸性位的接触准则被简单描述为“越接近越好”金属与酸性位的距离过大，异构烯烃中间体会进行二次反应，使气体产物选择性上升，同时积碳也会增加Feed 烷烃分子D:diesel G:gas2.实验32.1催化剂制备50wt%Y型沸石(介孔)与50wt%-Al2O3粘结剂挤条成型 Y/A8mm2mm研磨筛分0.2-0.5mmY/A 颗粒在PH=5的条件下与Pt(NH3)4(NO3)2进行离子交换（Pt位于在分子筛上）在PH=3的条件下与H2PtCl6通过静电吸调控Pt离子的落点（Pt位于氧化铝上）0.6wt%Pt-Y/A0.7wt%Pt-A/Y介孔Y型分子筛（Si/Al=30)文章结构三种进料在两类催化剂上的模型反应n-C10,n-C19和i-C19（2,6,10,14-四甲基十五烷）转化率转化率35%时的烃类产物的碳数分布图单因素实验 -仅Pt落点不同Pt-Y/A 分子筛形貌：Pt纳米颗粒在分子筛晶体中，微孔内；Y/A挤出物的结构：EDX elemental mappingPt-A/Y 分子筛形貌：Pt纳米颗粒分布于氧化铝上表征：HAADF-STEM电子断层成像（electron tomography)产物选择性催化性能评价双功能催化剂的结构形貌机理解释5Pt颗粒具有相似的粒径，且负载量接近（0.6%）(ICP-OES)与Y/A挤出物相比，负载金属后并未改变其结构性质NH3-TPD显示两种催化剂酸性相似除Pt落点不同，结构参数相同纳米尺度的接触对烃类转化活性和选择性的影响催化剂评价正癸烷转化反应在高通量反应器中评价50mg催化剂；0.45MPa；W/F=1400Kg S mol-1,H2/正癸烷=214采用固定床反应器进行催化剂评价反应气体：正十九烷溶解于正庚烷(十九烷浓度1%);280气化并与 H2混 合 通 入 反 应 器（200mg催 化 剂，0.65MPa；H2/hydrocarbon=14.6 W/F=713Kg S mol-1）惰性 异十九烷（2,6,10,14-四甲基十五烷）采用同样的条件实验部分67EDX elemental mappingFigure 1.Distribution of zeolite Y and alumina components within Y/A extrudates.a,EDX map of a 70-nm-thick section of a Y/A extrudate,showing the location of silicon(Si,green)and aluminium(Al,red),which are indicative of the presence of the zeolite Y and alumina components,respectively,of Y/A.b,EDX map showing only the Si(green)signal,corresponding to the presence of zeolite Y.c,EDX map showing only the Al(red)signal,most pronounced in regions containing pure alumina phase.Scale bars,2 m.分析的样品：由超薄切片机切割Y/A得到的一片70nm厚度的切片两种成分纳米尺度混合，分子筛晶体（500-1000nm）被至少一层氧化铝包围有孔道结构（BET佐证）8HAADF-STEM High-angle annular dark-field scanning transmission electron microscopyFigure 3|The HAADF-STEM image(a)is of a 70-nm-thick section of a Pt-Y/A sample.Shown are an HAADF-STEM image(c)and EDX map(d)of a 70-nm-thick section of Pt-A/Y Scale bars,50 nm.Pt-Y/APt-A/YPt-Y/A上Pt颗粒的粒径分布较窄，约2.5nm且只位于分子筛晶体内Pt-A/Y上Pt粒子约3.5nm，且只位于挤出物中的氧化铝上；分子筛晶体内没有Pt颗粒可通过电子断层成像证实9HAADF-STEM High-angle annular dark-field scanning transmission electron microscopyFigure S2.Controlled deposition of platinum.a,Left,an HAADF-STEM image of a 70-nm-thick section of the Pt-Y/A catalyst.Right,EDX elemental maps of the region outlined in green in the HAADF-STEM image.The EDX maps show the presence of Pt particles(yellow)in the zeolite region(green,with the dominant Si signal);the alumina region(red)is empty.O denotes the oxygen signal.b,Left,an HAADF-STEM image of a 70-nm-thick section of the Pt-A/Y catalyst.Right,EDX elemental maps of the region outlined in red at the left.Pt particles(yellow)are present in the alumina region(red),while the zeolite crystal(green)contains no Pt particles.The bright spot and line in the HAADF-STEM image of Pt-A/Y,below the mapped region of interest,originate from prolonged electron-beam exposure.Scale bars in the EDX maps represent 50 nm.Scale bars in the EDX maps represent 50nm.Pt-Y/APt-Y/APt-A/Y10Figure S3Three-dimensional structural analysis using electron tomography.Pt-Y/APt-A/Y2.5nm的 Pt颗粒位于分子筛晶体内部；氧化铝上只有很微量的Pt颗粒Pt-A/Y上Pt颗粒位于氧化铝上；没有Pt颗粒在分子筛晶体内部催化剂乙醇处理超声分散，使分子筛晶体和粘结剂氧化铝分离后TEM观察11Figure 4|Impact of nanoscale intimacy on hydrocracking activity.ac,The percentage of alkane feedstock converted is shown against the reaction temperature for Pt-Y/A(green squares)or Pt-A/Y(red triangles)catalysts.The feedstocks are:a,n-decane(n-C10);b,n-nonadecane(n-C19);n-C10与n-C19转化率相同;i-C19（2,6,10,14-四甲基十五烷）在Pt-A/Y上转化率较低是由于体积较大的i-C19烯烃分子传输受到了限制，i-C19的烯烃分子扩散速率较慢；正烯烃的在Y型分子上内的扩散速率1.0 x10-9m2/S ，i-C19烯烃分子的值为 1.0 x10-11m2/S 模型反应烃类的转化率12Figure 4|Impact of nanoscale intimacy on hydrocracking activity.df,Product yields from d,n-decane,e,n-nonadecane,and f,pristane feedstocks,when using Pt-Y/A(green)or Pt-A/Y(red)catalysts.Solid lines and filled symbols show the yields of isomerized products;dashed lines and open symbols show cracked products.Experiments were performed at a pressure of 0.45 MPa and a H2/hydrocarbon molar ratio of 214(n-decane);or a pressure of 0.65 MPa and a H2/hydrocarbon molar ratio of 14.6(n-nonadecane and pristane).在Pt-A/Y上骨架异构体更多，说明了脱氢位和酸性位保持纳米尺度的接触对双功能催化剂的选择性很重要;模型反应产物的产率13相同转化率下n-C10上的裂解产物两种催化剂上一致;n-C19在Pt-A/Y上产物集中于C10-C19；而在Pt-Y/A上则集中于气相产品C3-C4和轻石脑油（C5-C9）14Pt-Y/A上，原料分子必须通过微孔扩散到金属位上；烯烃中间体很容易陷入到分子筛的微孔里进行二次反应；在Pt-A/Y上，Pt颗粒位于氧化铝上，烯烃从分子筛上扩散出去并进行异构化反应；催化活性和选择性不仅依赖于活性位和反应物间的距离还依赖于反应物分子在活性位间的传输扩散的难易程度；设计了新方法调控了金属与酸性位保持纳米尺度的接近，极大的影响了产物的选择性4.结论151617催化剂制备50wt%Y型沸石(介孔)与50wt%-Al2O3粘结剂挤条成型 Y/A8mm2mm研磨筛分0.2-0.5mmY/A 颗粒1.485gY/A粒子悬浮于450ml Milli-Q超纯水室温下搅拌1h,保持悬浮液的PH=6.4；悬浮液中加入50ml 含Pt(NH3)4(NO3)2 29.8mg的溶液，搅拌3h，PH至4.9，过滤洗涤，120干燥，600下H2还原6h 0.6Pt-Y/A (Pt在分子筛上）1.491g Y/A粒子悬浮于450ml Milli-Q超纯水室温下搅拌1h,保持悬浮液的PH=6.2，加入1M HCl使PH到 2.6；悬 浮 液 中 加 入 50ml 含 H2)PtCl66H2O 22.5mg的溶液，搅拌3h，PH至4.9，过滤洗涤，120干燥，600下H2还原6h 0.7Pt-Y/A (Pt在铝的表面）18Figure S4 Comparing the acidity of the samples.Temperature-programmed desorption of ammonia by the Pt-Y/A(green)and Pt-A/Y(red)catalysts displays peaks that indicate the presence ofweakly acidic(at 160)and strongly acidic(at 320 C)sites within both catalysts,with Pt-A/Y showing slightly lower peak intensity in the region of the weakly acidic site.The total amount of ammonia desorbed was measured to be 14.3 cm3 g1(Pt-Y/A)and 14.7 cm3 g1(Pt-A/Y)STP.160：弱酸位的吸附 320：强酸位的吸附NH3-TPD19BET Figure S1 a.N2 physisorption isotherm(adsorption and desorption);b.The BarrettJoynerHalenda(BJH)pore-size distribution回滞环的存在证明有介孔，孔径分布大多集中于介孔和大孔20