合成选择大小尺寸的负载金纳米粒研究多相和均相CAT过程翻译.pdf

4596 J. Phys. Chem. C 2007, 111, Synthesis and Size-Selective Catalysis by Supported Gold Nanoparticles: Study on Heterogeneous and Homogeneous Catalytic Process Sudipa Panigrahi,† Soumen Basu,† Snigdhamayee Praharaj,† Surojit Pande,† Subhra Jana,† Anjali Pal,‡ Sujit Kumar Ghosh, and Tarasankar Pal*,† Department of Chemistry, Indian Institute of Technology, Kharagpur-721302, India, and Department of Ci il Engineering, Indian Institute of Technology, Kharagpur-721302, India Recei ed: Noember 14, 2006; In Final Form: December 20, 2006 Coreshell nanocomposites (RAu) bearing well-defined gold nanoparticles as surface atoms of variable sizes (855 nm) have been synthesized exploiting polystyrene-based commercial anion exchangers. Immobilization of gold nanoparticles, prepared by the Frens method, onto the resin beads in the chloride form is possible by the ready exchange of the citrate-capped negatively charged gold particles. The difficulty of nanoparticle loading, avoiding aggregation, has been solved by stepwise operation. Analysis of the gold particles after immobilization and successive elution confirm the unaltered particle morphology while compared to those of the citrate-capped gold particles in colloidal dispersion. It was observed that the rate of the reaction increases with the increase in catalyst loading, which suggests the catalytic behavior of the gold nanoparticles for the reduction of the aromatic nitrocompounds. The rate constant, k, was found to be proportional to the