Size-Controlled Synthesis of Highly Stable and Active Pd@SiO2 Core-Shell Nanocatalysts for Hydrogenation of Nitrobenzene

Pd@SiO2 core shell nanoparticles were successfully synthesized by a sol gel method: Tetradecyl. trimethyl ammonium bromide capped Pd nanoparticles were coated with SiO2 through the hydrolysis of tetraethylorthosilicate. The as synthesized Pd@SiO2 particles consist of : Pd :cores with a. particle size of 3.7 nm and. SiO2. shells with a thickness from 10 to 30 nm at different synthetic conditions. The "Pd@SiO2 nanocatalysts with 1.9-2.4 nm mesoporous SiO2 shells were generated after removal of tetradecyl trimethyl. ammonium bromide from Pd@SiO2 core shell particles by calcination and following H-2 reduction The relevant characterizations such as XRD, TEM, FT-IR, and BET were carried out for Pd@SiO2 particles, and the results showed that the Pd@SiO2 nanocatalysts were highly stable with the protection of silica shells, and the Pd cores did not increase during. thermal treatment and H-2 reduction. The studies of catalytic CO oxidation at high temperatures and hydrogenation of nitrobenzene With H-2 were tested for Pd@SiO2 nanocatalysts, and the results indicated that Pd@SiO2 nanocatalysts were stable at high temperatures and highly active and stable for hydrogenation of nitrobenzene even after long time use.