Metal particles in Pt/1bAl2O3 and Ni/1bAl2O3 composites prepared by the reduction of the xerogels have been investigated by high resolution electron microscopy and x-ray diffraction. The alumina phase is essentially amorphous while the metal particles are crystalline. The average size of the metal particles increases with the metal content in the composites. Pt atoms exhibit a greater tendency to form metal clusters than the Ni atoms. At low metal concentrations (≲ 0.25 wt%), the number of atoms in the metal particles is in the range 100–400. Lattice resolution of the metal particles has been observed in HREM images. The cubic phase of ZrO2 is stabilized in Ni/1bZrO2 composites, the stability increasing with the Ni content.
Discussion(0)
No comments yet. Be the first to comment.