载Au纳米SiO₂催化剂的自组装制备及光谱研究

来源期刊：有色金属2010年第4期

论文作者：谢娟 何乐芹 孟晓彩 谢艳 李艳廷

文章页码：22 - 26

关键词：催化剂材料； Au/SiO₂催化剂； 自组装； 制备； UV-Vis谱

Key words：catalysis material； Au/SiO₂ catalysts； self-assembly； preparation； ultraviolet-visible spectra

摘    要：采用表面改性方法将硅烷偶联剂(MPTMS)接枝在纳米级SiO₂表面,实现表面巯基化修饰。通过金硫键实现金纳米颗粒在SiO₂载体上的自组装,高温固化得到Au/SiO₂纳米复合结构催化剂。运用红外光谱、热分析仪、透射电镜、X射线衍射、原子吸收光谱和紫外-可见光谱等对其进行表征。结果表明,所得Au/SiO₂纳米复合物结构稳定,金纳米颗粒均匀分布在SiO₂表面,粒度小且无团聚现象。根据紫外-可见吸收光谱中吸收峰的位置和强度能够对复合催化剂中Au组分的粒径大小及含量进行快速、准确的定性及定量分析。在实验负载量范围内,Au/SiO₂催化剂在520nm的吸光度与纳米金的负载量成线性关系,线性相关系数为0.997。

Abstract: By the method of surface modification,silane coupling agent (MPTMS) is grafted on the surface of nano-sized silica,and the surface of silica is functionalized with thiol groups.Gold nanoparticles are self-assembled on SiO₂ through Au-S bond between the gold nanoparticles and the surface thiol-groups of SiO₂.Nanocomposite catalysts of Au/SiO₂ are obtained after calcination at high temperature.The samples are characterized by FTIR,TG-DTA,TEM,XRD,AAS and UV-Vis techniques.Results show that the Au/SiO₂ nanocomposites have stable structure,and gold nanoparticles are highly dispersed on the support surface.It is found that based on the location and intensity of absorption peaks,the size and content of gold component in Au/SiO₂ nanocomposite catalysts can be measured by UV-Vis spectra rapidly and exactly.At 520 nm the relation between absorbance and Au loading of Au/SiO₂ catalysts is linear and the pertinent coefficient reaches 0.997 in the range of loading in these experiments.