School of Material and Chemical Engineering, Zhengzhou University of Light Industry, 5 Dongfeng Road, Zhengzhou, 450002, P. R. China.
Dalton Trans. 2011 Nov 7;40(41):10857-64. doi: 10.1039/c1dt10374a. Epub 2011 Jun 2.
This work is directed towards the synthesis of multifunctional nanoparticles composed of Fe(3)O(4)-Au nanocomposite cores and a porous silica shell (Fe(3)O(4)-Au/pSiO(2)), aimed at ensuring the stability, magnetic, and optical properties of magnetic-gold nanocomposite simultaneously. The prepared Fe(3)O(4)-Au/pSiO(2) core/shell nanoparticles are characterized by means of TEM, N(2) adsorption-desorption isotherms, FTIR, XRD, UV-vis, and VSM. Meanwhile, as an example of the applications, catalytic activity of the porous silica shell-encapsulated Fe(3)O(4)-Au nanoparticles is investigated by choosing a model reaction, reduction of o-nitroaniline to benzenediamine by NaBH(4). Due to the existence of porous silica shells, the reaction with Fe(3)O(4)-Au/pSiO(2) core/shell nanoparticles as a catalyst follows second-order kinetics with the rate constant (k) of about 0.0165 l mol(-1) s(-1), remarkably different from the first-order kinetics with the k of about 0.002 s(-1) for the reduction reaction with the core Fe(3)O(4)-Au nanoparticles as a catalyst.
这项工作致力于合成由 Fe(3)O(4)-Au 纳米复合材料核和多孔硅壳 (Fe(3)O(4)-Au/pSiO(2)) 组成的多功能纳米粒子，旨在确保磁性-金纳米复合材料的稳定性、磁性和光学性质。所制备的 Fe(3)O(4)-Au/pSiO(2) 核/壳纳米粒子通过 TEM、N(2)吸附-解吸等温线、FTIR、XRD、UV-vis 和 VSM 进行了表征。同时，作为应用的一个例子，通过选择一个模型反应，即 NaBH(4)还原邻硝基苯胺为苯二胺，研究了多孔硅壳包裹的 Fe(3)O(4)-Au 纳米粒子的催化活性。由于存在多孔硅壳，以 Fe(3)O(4)-Au/pSiO(2) 核/壳纳米粒子作为催化剂的反应遵循二级动力学，速率常数 (k) 约为 0.0165 l mol(-1) s(-1)，与以核心 Fe(3)O(4)-Au 纳米粒子作为催化剂的反应的 k 约为 0.002 s(-1)的一级动力学明显不同。
