Preparation And Stabilization Of Palladium Nanoparticles Inside Mesoporous Materials And Metal Oxide

Metal nanoparticles, because of their excellent properties such as large specific surface area and high surface energy, were widely used in catalysis, biomedical, energy and many other fields. However, serious aggregation was usually happened when they used in practice, and resulted in the degradation of performance even inactivation. Therefore, how to design effect method to stabilize metal nanoparticles was the key to ensure their best use.Mesoporous materials, as to their regular mesoporous structure and high specific surface area, were usually regarded as the carrier of metal nanoparticles. Through the restriction of channels, not only realized the stabilization of metal nanoparticles, but also contributed to the transportation of reactants. Metal oxides, which could interact with metal nanoparticles and improved their performance, were also used to support and disperse metal nanoparticles. Base on the stabilization of metal nanoparticles, three kinds of metal/supporter nanocomposites were synthesized by using mesoporous materials and metal oxide as the supporter respectively.?1? A simple and effective method was developed for the controlled anchoring of Pd nanoparticles inside the channels of MCM-41. So that, Pd/MCM-41 with tiny metal size ?-3 nm?, high stability and activity was obtained. This material exhibited good catalytic activity in the couple reaction of iodobenzene and phenylboronic acid. After 5 minutes'reaction, the conversion of iodobenzene reached 91.42% and didn't observe obvious decrease after recycling 4 times.?2? Carbon sphere with well mesoporous structure, high specific surface area and uniform pore size was synthesized by using SiO₂ nanoparticles as the template. Pd nanoparticles could be well dispersed in the mesopores of this carbon spheres and got Pd/meso-Carbon. This materials showed excellent catalytic activity in the couple reaction of iodobenzene and phenylboronic acid. The conversion of iodobenzene reached 99.06% after reacting 5 minutes, and remained high activity after recycling 7 times.?3? Pd/TiO₂ hollow nanosphere with well hollow structure and uniform coating layer was prepared. The metal loading amount and the thickness of TiO₂ layer can be easily adjusted by changing the reaction condition. Used the Pd/TiO₂ hollow nanosphere as catalyst to catalytic the couple reaction of iodobenzene and phenylboronic acid, after 5 minutes'reaction, the conversion of iodobenzene reached 96.06%. The system could be extended by changing the species of metal salt, and obtained different kinds of metal/TiO₂ hollow nanosphere.