Direct synthesis and characterization of gold and other noble metal nanodispersions in sol-gel-derived organically modified silicates
Direct synthesis and characterization of gold and other noble metal nanodispersions in sol-gel-derived organically modified silicates
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作者：
Bharathi, S;Fishelson, N;Lev, O
提出了在有机改性硅酸盐中制备贵金属纳米分散体的一般方法，特别强调金纳米分散体的合成及其表征。含有胺官能团的有机改性溶胶-凝胶单体用于在还原步骤之前稳定金属盐，并在还原之后以及通过凝胶形成、干燥和老化来封端和防止金属溶胶凝结。得到平均直径为4-6 nm的均匀球形Au、Pt和Pd金属纳米分散体。通过相同方法制备的银纳米颗粒的粒径分布和平均尺寸明显更大。这是由于银-胺络合物的稳定性较低以及胺对银表面的亲和力较低。通过这种途径可以制备稳定的胶体水溶液和多孔薄膜和整料中的负载金属纳米分散体。
A general approach to prepare nanodispersions of noble metals in organically modified silicates is presented with particular emphasis on the synthesis of gold nanodispersion and its characterization. Organically modified sol-gel monomers containing amine functional groups are used to stabilize the metal salts before the reduction step and to cap and prevent coagulation of the metal sol after reduction and through gel formation, drying, and aging. Uniform spherical metal nanodispersions of Au, Pt, and Pd with average diameter of 4-6 nm were obtained. The particle size distribution and the average size of silver nanoparticles prepared by the same method were considerably larger. This was attributed to the lower stability of the silver-amine complex and to the lower affinity of amines to silver surfaces. Stable aqueous colloidal solutions and supported metal nanodispersions in porous films and monoliths can be prepared by this route.