Development of advanced catalysts from the intermetallic compounds between two transition metals

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Advanced catalysts have been developed with intermetallic compounds prepared between two transition metals. Transition metals of Pt, Pd, Ni and Co were combined with Ti, Zr, V, Cr, etc.to form intermetallic compounds by melting these mixtures. Obtained ingots were crushed in air and sieved into small particles (d<25 μm). XRD revealed the formation of the aimed intermetallic compound. CO_2 reforming of methane was carried out on Co-or Ni-based compounds. It was found that the compounds between Co and Hf were highly active and stable for the formation of CO and H_<2-> In the case of FT synthesis, RuTi intermetallic compound was revealed to be the selective catalyst for the formation of higher hydrocarbons. CVD of titanocene dichloride onto Ru/SiO_2 gave fine particles of RuTi dispersed on the surface of SiO_2 and these particles were also selective for FT synthesis. TiPt_3 was found to be more active than Pt for ethylene hydrogenation and H_<2^->D_2 equilibration. Three preparation methods, high-temperature reduction of Pt/TiO_2, CVD of titanocene dichloride onto Pt/SiO_2, and successive impregnation of Pt onto TiO_x/SiO_2, were applied to obtain fine particles of TiPt_3. The successive impregnation gave fine particles of Pt totally covered by layers of active TiPt_3. They were more active than Pt/SiO_2 for ethylene hydrogenation and H_<2^->D_2 equilibration and highly selective for the formation of butenes in butadiene hydrogenation. Therefore, it is found that the successive impregnation gives the catalyst with equal activity and selectivity to TiPt_3 fine particles.