Preparation of TiPt_3 fine particles having higher catalytic activity than Pt

摘要

Ti-Pt intermetallic compounds were prepared by arc melting the stoichiometric mixture of Ti and Pt. TiPt_3 crushed in air and reduced in flowing hydrogen was found to be more active than Pt powder for H_2-D_2 equilibration and ethylene hydrogenation. It was selective for the formation of butenes in 1,3-butadiene hydrogenation, whereas Pt hydrogenated butadiene into butane. To obtain the fine particles of TiPt_3 intermetallic compound, the reduction of Pt/TiO_2, the CVD of titanocene onto Pt/SiO_2 and the successive impregnation of Pt onto TiO_2/SiO_2 were examined. The successive impregnation catalyst with Ti/Pt=1/3 was more active than Pt/SiO_2 for the ethylene hydrogenation and highly selective for the butene formation in butadiene hydrogenation. The XRD pattern of this catalyst indicated the diffraction of Pt metal with crystallite diameter of ca. 4 nm. It is concluded that the successive impregnation catalyst contains Pt fine particles completely covered by the layer of active and selective TiPt_3.