Wu Chien-Chen, Chen Dong-Hwang
Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan, 701, Republic of China.
Nanoscale Res Lett. 2012 Jun 19;7(1):317. doi: 10.1186/1556-276X-7-317.
A novel magnetically recoverable Au nanocatalyst was fabricated by spontaneous green synthesis of Au nanoparticles on the surface of gum arabic-modified Fe3O4 nanoparticles. A layer of Au nanoparticles with thickness of about 2 nm was deposited on the surface of gum arabic-modified Fe3O4 nanoparticles, because gum arabic acted as a reducing agent and a stabilizing agent simultaneously. The resultant magnetically recoverable Au nanocatalyst exhibited good catalytic activity for the reduction of 4-nitrophenol with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increase in the amount of Au nanocatalyst or decrease in the initial concentration of 4-nitrophenol. The kinetic data suggested that this catalytic reaction was diffusion-controlled, owing to the presence of gum arabic layer. In addition, this nanocatalyst exhibited good stability. Its activity had no significant decrease after five recycles. This work is useful for the development and application of magnetically recoverable Au nanocatalyst on the basis of green chemistry principles.
通过在阿拉伯胶修饰的Fe3O4纳米颗粒表面自发绿色合成金纳米颗粒，制备了一种新型的可磁回收金纳米催化剂。由于阿拉伯胶同时作为还原剂和稳定剂，在阿拉伯胶修饰的Fe3O4纳米颗粒表面沉积了一层厚度约为2nm的金纳米颗粒。所得的可磁回收金纳米催化剂对硼氢化钠还原4-硝基苯酚表现出良好的催化活性。根据准一级动力学模型评估的速率常数随着金纳米催化剂用量的增加或4-硝基苯酚初始浓度的降低而增加。动力学数据表明，由于存在阿拉伯胶层，该催化反应是扩散控制的。此外，该纳米催化剂表现出良好的稳定性。经过五次循环后，其活性没有显著降低。这项工作基于绿色化学原理，对可磁回收金纳米催化剂的开发和应用具有重要意义。
