Catalytic properties of intermetallic compounds and their application to high performance catalysts

研究了金属间化合物的催化性能及其作为特定催化剂在各种反应中的应用。采用电弧熔炼技术制备了过渡元素和典型元素以及两种过渡元素组合的金属间化合物。在表征和催化反应之前，将它们在空气中粉碎，并在600-900℃的氢气中还原。X射线衍射、X射线光电子能谱和能谱分析表明，它们在体相和表面都是均一的单相金属间化合物。对于H_2-D_2平衡，Ni3Sn和Pt3Ge的催化活性远低于Ni和Pt3Ge，但对乙炔部分加氢制乙烯和丁二烯部分加氢制丁烯的选择性要高得多。TiPt3对H_2-D_2平衡和乙烯加氢具有比铂更高的活性，采用化学气相沉积(CVD)或连续浸渍技术制备了这些金属间化合物的超细颗粒。在化学气相沉积中，…的蒸气在Ni/SiO_2、Pt/H-ZSM-5、Ru/SiO_2等催化剂上加氢，使第二种元素沉积在第一种元素的颗粒上。X-射线衍射、X-射线光电子能谱和X-射线光电子能谱分析表明，所合成的颗粒为单相金属间化合物，直径为4-20 nm。细颗粒显示出比无载体的块状化合物高三个数量级的每重量化合物的活性。此外，这些化合物的选择性与负载型纯金属完全不同。Ni_3SN/SiO_2在环己烷反应中生成苯，而Ni/SiO_2几乎完全生成甲烷。Pd_3Bi/SiO_2和Pd_3PB/SiO_2在甲苯的氧化乙酰氧基化反应中生成乙酸苄酯，产率远高于Pd/SiO_2。Pt3Ge/H-ZSM-5催化剂在丁烷芳构化反应中加速了芳香烃的生成，而没有通过氢解优先生成甲烷。在费托合成中，RuTi/SiO_2比Ru/SiO_2具有更高的产率。较少

The catalytic properties of intermetallic compounds and their application to various reactions as specific catalysts were investigated.Intermetallic compounds with the combination of transition and typical elements and of two transition elements were prepared by an arc-melting technique. They were crushed in air and reduced by hydrogen at 600-900℃ before characterization and catalytic reactions. XRD, XPS and EDX studies revealed that they were homogeneous and single-phase intermetallic compounds in the bulk and on the surface. Ni_3Sn and Pt_3Ge gave much lower catalytic activity than Ni and Pt for H_2-D_2 equilibration but much higher selectivity for partial hydrogenation of acetylene into ethylene and 1,3-butadiene into butenes, respectively. TiPt__3 gave higher activity than Pt for H_2-D_2 equilibration and ethylene hydrogenation.Fine particles of those intermetallic compounds were prepared by chemical vapor deposition (CVD) or successive impregnation techniques. In CVD, the vapor of … More Sn(CH_3)_4, Ge(acac)_2Cl_2, Ti(C_5H_5)_2Cl_2, etc. was supplied with hydrogen onto Ni/silica, Pt/H-ZSM-5, Ru/silica, etc. to deposit the second element onto the particle of first element. XRD, XPS and XAFS studies revealed that the particles were single-phase intermetallic compounds with diameters of 4-20 nm. The fine particles showed three magnitude higher activity per weight of compounds than the unsupported bulk compounds. Moreover, the selectivity of these compounds was totally different from that of supported pure metals. Ni_3Sn/silica gave benzene in the reaction of cyclohexane, while Ni/silica gave almost exclusively methane. Pd_3Bi/silica and Pd_3Pb/silica gave benzyl acetate in the oxidative acetoxylation of toluene with much higher yields than Pd/silica. Pt_3Ge/H-ZSM-5 accelerated the formation of aromatic hydrocarbons in the aromatization of butane without preferential formation of methane through the hydrogenolysis on Pt/H-ZSM-5. RuTi/silica exhibited high yield to higher hydrocarbons in Fischer-Tropsch synthesis than Ru/silica. Less