Immobilization of highly active Pd nano-catalysts on functionalized mesoporous silica supports using mercapto groups as anchoring sites and their catalytic performance for phenol hydrogenation

Highly active and highly dispersed Pd-loaded nano-catalysts using mercapto group (-SH) functionalized mesoporous silica supports, namely, Pd-SH-MCM-41 and Pd-SH-SBA-15, were prepared using an impregnation-reduction approach. The surface -SH groups are believed to facilitate the high distribution and immobilization of the Pd nanoparticles within the silica supports through an anchoring interaction. The catalysts featured long-range ordered structures, uniform pore size, high surface area, and highly dispersed Pd nanoparticles as characterized by X-ray diffraction, N-2 adsorption-desorption, and transmission electron microscopy. The catalysts showed activity five times higher than that of commercial Pd/C catalyst and three times higher than those of Pd/MCM-41 and Pd/SBA-15 catalysts. Within 1 h of reaction at 80 degrees C and 1.0 MPa, the conversion of phenol attained was greater than 99%, and the selectivity for cyclohexanone was 98%. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved