Study Of Au,Pd Supported On Ordered Mesoporous Carbons And Polyacetylene-modified Pd Supported On Metal-organic Framework Catalysts

Catalysts are of vital importance for industrial production and scientific research.The stability and accessibility of metal catalysts are believed to play a pivotal role in its application in all fields. We thus report two novel strategies to fabricate two supported metal catalysts with excellent stability and good accessibility to the reactants.Mesoporous materials, such as mesoporous silica, mesoporous alumina and some mesoporous carbon materials derived from various templates with rigid mesoporous structures are highly attractive as supports for designing noble metal nanoparticles due to their excellent thermal stability. Herein, we report a novel strategy to fabricate porous graphite spheres with a well-defined mesoporous structure derived from 3D multicomponent colloidal spheres via a process comprising self-assembly,carbonization and selective etching. The as-prepared structures have porosity and rigidity that endow the metal nanoparticles (NPs) with an outstanding dispersity,thermal stability and accessibility, making them an excellent model catalyst. The BET surface area of as-prepared ordered mesoporous carbons(OMCs) is 1461.0653 m2 g-1 and the size of its pore is about 7.5 nm. The reinforced mesoporous carbon shell of Au@OMCs could effectively avoid the aggregation of Au NPs at high temperatures(800 ?) and maintain the good accessibility to the reactants. Actually, this strategy of preparing Au@OMCs from multicomponent 3D colloidal spheres can be generalized to other metals such as Pd, if the two building blocks were sophisticatedly designed.A thin layer of hydrophobic polyacetylene was successfully coated onto the surface of the nanocomposite Pd-ZIF-67 by a facile polymerization process of C2H2,and the Pd site accessibility of Pd-ZIF-67 was retained after polyacetylene coating. The thin layer of hydrophobic polyacetylene endow the surface of ZIF-67 with excellent hydrothermal stability, a hollow dodecahedral structure was obtained after etching of H2O, rendering the nanocomposite a higher specific surface area. Remarkably, the hydrophobic polyacetylene facilitates the enrichment catalytic activity of Pd, while also affording protection of the surface of ZIF-67.