Author/Authors :
Lambert، نويسنده , , Stéphanie D. and Gommes، نويسنده , , Cédric and Alié، نويسنده , , Christelle and Tcherkassova، نويسنده , , Natalia and Pirard، نويسنده , , Jean-Paul and Heinrichs، نويسنده , , BENOIˆT STIJLEMANS، نويسنده ,
Abstract :
Pd–Ag/SiO2 and Pd–Cu/SiO2 xerogel catalysts have been synthesized by cogelation of tetraethoxysilane (TEOS) and chelates of either Pd and Ag or Pd and Cu with 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS). After an extensive study of the influences of synthesis operating variables over structural characteristics of gels, highly dispersed bimetallic Pd–Ag/SiO2 and Pd–Cu/SiO2 xerogel catalysts were obtained. These samples are then composed of completely accessible Pd–Ag and Pd–Cu alloy crystallites with sizes of 2–3.5 nm located inside silica particles exhibiting a monodisperse microporous distribution. It appears also that the metal complex acts as a nucleation agent in the formation of silica particles.
