Synthesis Gold-Silver Alloy Nanoparticles In Reverse Microemulsion And Their Catalysis For CO Oxidation

Metallic nanoparticles. particularly gold-silver alloy nanoparticles, have stimulated an increasing interest due to their unique optical, electronic and catalytic properties, especially as catalyst for CO oxidation. Monodisperse nanoparitcles can be synthesized in reverse microemulsions, and the size of nanoparticles can be limited by the droplets in reverse microemulsions, which make the reverse microemulsion route much more popular. Nonionic surfactants C11E3 and C11E5 which are independent of metal salts and keep the system free of catalystic toxicant sulfur were chosen to form the reverse microemulsion system. In this thesis, we synthesis gold-silver alloy nanoparticles in reverse microemulsion and investigate their catalysis for CO oxidation. Main points of the thesis work are bellow:1. Draw phase diagram of the reverse microemulsion used in the synthesis of nanoparticles. Choose the compositon of three compounds.2. Synthesis gold, silver and gold-silver alloy monodisperse nanopaticles with the size of 5-10nm in the reverse microemulsions.3. Achieve nanoporous gold-silver alloy nanoparticles by selective dealloying. Investigate the kinetic of the dealloying, gold-silver alloy could be selective dealloyed by HNO3 because the silver would be oxidized much faster than the gold.4. Evaluate the catalytic activity of the gold, silver, gold-silver alloy and nanoporous gold-silver alloy nanoparticles loaded on Y-Al2O3 support for CO oxidation. The nanoporous gold-silver alloy (Ag:Au=50:50) nanoparticles shows the highest catalysis activity because of the synergetic effect and the size effect.