Au@SiO_2中空微球的制备及催化性能

以天然高分子阿拉伯树胶(AG)为还原剂和稳定剂制备了金纳米粒子;将含有金纳米粒子(Au NPs)、阿拉伯树胶和氨水的溶液滴加到乙醇中形成AG-Au NPs复合胶团;利用正硅酸乙酯水解,在AG-Au NPs表面包覆二氧化硅壳层;通过简单水洗的方法得到了金纳米粒子@二氧化硅(Au@SiO_2)中空微球.采用透射电子显微镜(TEM)、X射线衍射仪(XRD)和氮气吸附实验等对Au@SiO_2中空微球进行表征.通过设计对比实验,证实阿拉伯树胶在中空结构形成过程中起到模板剂的作用.催化性能测试结果表明,所制备的Au@SiO_2中空微球在硼氢化钠还原亚甲基蓝的反应中表现出良好的催化活性和重复使用性.

Preparation of Gold Nanoparticles Loaded Hollow Silica Spheres and Their Catalytic Performance

A natural polymer of Arabic gum was chosen as the reducing and stabilizing agent to synthesize Au nanoparticles.The Arabic gum and Au nanoparticles(AG-Au) hybrid colloids were obtained by dropping the mixture of the Au nanoparticles,Arabic gum molecules and ammonia solution into ethanol.Tetraethyl orthosilicate (TEOS) was added into the system to form a silica layer on the as-prepared AG-Au hybrid colloids.Finally,the Au loaded silica(Au@SiO2) hollow particles were produced by simply water washing.For the Au@SiO2hollow particles characterization,transmission electron microscope(TEM),X-ray diffraction(XRD) and N2 adsorption-desorption measurement were conducted.The Arabic gum serves as the templating agent during the formation process of the Au@SiO2 hollow particles,which has been proved by control experiments.The asprepared Au@SiO2 hollow particles show good performance and stability in the catalytic reaction of reduction of methylene blue (MB) with NaBH4.