Palladium Nanoparticles Grafted on Mesoporous Silica: Highly Active and Selective Catalyst for Hydrogenation of Nitroaromatics

Background: Palladium nanoparticles grafted on mesoporous silica catalysts were successfully prepared by wet impregnation method. Method: In this method, palladium was reduced and stabilized by single reductive stabilizer using triethylaluminum (TEAL) or diethyl aluminum chloride (DEAC) and deposited on SiO2 support. The prepared catalysts were characterized by high-resolution transmission electron microscopy (HRTEM), BET surface area, X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and H2- chemisorption studies. Performance of catalysts was tested for hydrogenation of nitrobenzene and substituted aromatics in the liquid phase under atmospheric pressure at different temperatures. Results: High activity and selectivity was observed with a turn over frequency of 8.62 X 104 h-1. The H2-chemisorption studies shows that palladium dispersion was 40 %. Furthermore, the catalyst could be easily recovered from reaction mixture and was recycled three times without any significant loss in the activity.