Synthesis and Characterization of Pd/Ag/SiO₂ Nano-Composite Materials

Abstract

Pd/Ag/SiO2 sols and powder materials were prepared by adding AgNO3 and Pd (NO3)2·2H2O into a methyl-modified silica sol. Tetraethylorthosilicate and methyltriethoxysilane were used as the silica precursor for the sol-gel reaction. The obtained SiO2 sols and powder materials were characterized by sol particle size distribution, zeta potential analysis, UV-Vis spectra, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurement. It was found that most of the particle sizes of the prepared Pd/Ag/SiO2 sols are about 2~10 nm with narrow size distribution. The zeta potential of Pd/Ag/SiO2 sol with Pd/Ag molar ratio of 7.5/2.5 presents the highest value. The FTIR analysis substantiates that the Si-CH3 groups exist in the silica network and the formed Pd/Ag/SiO2 sol particles possess linear structure. XRD characterization indicates that the Pd2+ and Ag+ in the Pd/Ag/SiO2 materials had be reduced to Pd0 and Ag0, respectively, after annealed in a nitrogen atmosphere at 350°C.

Ru (III) Schiff‐base complex anchored on nanosilica as an efficient and retrievable catalyst for hydration of nitriles

“…Various protocols have been developed which transforms an active homogeneous metal complex into an effective heterogeneous catalyst by anchoring on solid supports such as silica, chitosan, titania, manganese dioxide, alumina, fluorapatite etc . Compared to the other solid supports, some specific reasons associated with silica such as inexpensive, easy availability, non‐toxicity high thermal stability, surface reactivity, melting point, rigidity etc . makes it one of the most significant supports for heterogenization of active metal complex by immobilization through co‐ordination.…”