Simultaneous Pd catalyst immobilization during synthesis of mesoporous silica

Simultaneous immobilization of Pd catalyst during the synthesis of mesoporous silica employing the structure directing agent of the thermo-responsive and chelate copolymer of poly(N-isopropylacrylamide-co-acrylic acid) to afford Pd/SiO2 catalyst is studied. Thanks to the structure directing agent of the thermo-responsive and chelate copolymer, the immobilization of the Pd catalyst and the synthesis of the catalyst support of mesoporous silica are combined into a one-pot process. Following the proposed method, the Pd/SiO2 catalyst, in which the size of the immobilized Pd nanoparticles is below 4.2 nm and the Pd weight content ranges from 0.5% to 10%, is fabricated. It is supposed that the Pd nanoparticles are encapsulated within the mesopores of the in situ synthesized mesoporous silica. The synthesized Pd/SiO2 catalyst is tested by three different model reactions including hydrogenation of nitrobenzene, hydrogenation of cinnamyl alcohol and Suzuki coupling reaction, and a robust and reusable Pd/SiO2 catalyst is demonstrated.

► The structure directing agent of a thermo-responsive and chelate copolymer for synthesis of mesoporous silica is employed.
► Simultaneous immobilization of Pd catalyst during synthesis of mesoporous silica is achieved.
► Immobilization of the Pd catalyst with high Pd content up to 10 wt% is achieved.
► The Pd/SiO2 catalyst is efficient and reusable.