基于磁性球形聚电解质刷制备可回收的银纳米催化剂  

Preparation of Recyclable Silver Nanocatalysts Immobilized on Magnetic Spherical Polyelectrolyte Brushes

作　　者：周倩 李莉[1] 张涛 付智楠 郭旭虹[1] ZHOU Qian;LI Li;ZHANG Tao;FU Zhinan;GUO Xuhong(School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China)

机构地区：[1]华东理工大学化工学院

出　　处：《华东理工大学学报（自然科学版）》2019年第4期541-547,共7页Journal of East China University of Science and Technology

基　　金：国家自然科学基金面上项目(51773061)

摘　　要：合成了包覆磁性纳米粒子的球形聚电解质刷(MSPB),并以MSPB为载体成功负载了可回收的催化剂MSPB-Ag粒子.采用动态光散射(DLS)、透射电镜(TEM)、热重分析仪(TGA)、等离子体发射光谱仪(ICP)和紫外-分光光度计(UV)等方法进行了表征.结果表明:制备的MSPB分布较窄,具有快速磁响应性和对pH敏感的性能.MSPB-Ag粒子中负载的Ag纳米粒子粒径均一,在硼氢化钠的作用下,对4-硝基苯酚的还原反应具有较好的催化活性,在外部磁场的作用下能被快速回收.该方法为金属纳米催化剂的制备和回收开辟了一条新路径.Metal nanoparticles have attracted more and more attention due to their high activity and selectivity in catalytic applications recently. Spherical polyelectrolyte brushes (SPB) have been proved to be excellent carriers for the generation and immobilization of metal nanoparticles and they are stable in water due to the steric electrostatic repulsion of the polyelectrolyte brush layer. In this paper, magnetic spherical polyelectrolyte brushes (MSPB) consist of a core of polystyrene embedded with magnetite particles and a well defined shell of negatively charged poly(acrylic acid)s (PAA) brush. Silver nanoparticles were synthesized with MSPB as a carrier by reduction of Ag^+ in the brush layer in presence of BH4^-. and characterized by dynamic light scattering (DLS), transmission electron microscope (TEM), thermal gravimetric analysis (TGA), and ultraviolet spectrophotometer (UV). The reduction of 4-nitrophenol was used as a benchmark reaction to investigate the catalytic ability and recyclability of silver nanoparticles. TEM images showed that magnetite particles were successfully embedded into the PS cores and Ag nanoparticles with diameter of 2.30 nm were immobilized in the MSPB. The prepared MSPB was narrowly dispersed, stable, pH sensitive, rapidly responsive to magnetic fields, and redispersible. The obtained MSPB-Ag composites were also narrowly dispersed and separated rapidly by external magnetic fields. High catalytic activity was found in the reduction of 4- nitrophenol by NaBH4 in the presence of MSPB-Ag composites. The activation energy of MSPB-Ag composites in the reaction was calculated to be 66.03 kJ/mol, which was approximate to the SPB-Ag composites. This proposed approach opens a new way for the preparation of recyclable metal nanocatalysts with high activity.

关 键 词：MSPB 银纳米粒子 催化剂 可回收 

分 类 号：TQ317[化学工程—高聚物工业]