Robust Fe3O4/SiO2-Pt/Au/Pd Magnetic Nanocatalysts with Multifunctional Hyperbranched Polyglycerol Amplifiers
Robust Fe3O4/SiO2-Pt/Au/Pd Magnetic Nanocatalysts with Multifunctional Hyperbranched Polyglycerol Amplifiers
复制标题
具有多功能超支化聚甘油放大器的鲁棒 Fe3O4/SiO2-Pt/Au/Pd 磁性纳米催化剂
DOI：
10.1021/la100556p
复制
发表时间：
2010-07-06
期刊：
影响因子：
3.9
通讯作者：
Xu, Weijian
中科院分区：
文献类型：
--
作者：
Zhou, Li;Gao, Chao;Xu, Weijian
本文报道了一种简单的制备多羧基超支化聚甘油(HPG)接枝SiO_2包覆氧化铁(Fe_3O_4/SiO_2)磁性杂化载体的方法。这种载体结合了Fe3O4和HPG的特点，易于磁分离，以及良好的分子结构和丰富的官能团。以接枝的HPG为模板，在磁性载体表面直接生长了铂、金、钯等多种贵金属纳米催化剂，具有超细、近单分散的尺寸(例如，铂、金和钯的平均尺寸分别为4.8+/-0.5、6.0+/-0.6和4.0+/-0.4 nm)和高的覆盖密度。由于HPG的放大作用，纳米催化剂对铂、金和钯的负载量分别为0.296、0.243和0.268 mmoL/g左右。以对硝基苯酚还原、醇氧化、Heck反应等为代表的催化反应表明，贵金属纳米催化剂具有较高的催化活性。由于HPG模板的稳定性，纳米催化剂可以很容易地被磁体回收并高效地重复用于下一步的反应。这种强大的多功能磁性杂化材料将在催化和其他领域如药物输送和生物分离方面获得重要应用。
Here we report a facile approach to prepare multicarboxylic hyperbranched polyglycerol (HPG)-grafted SiO2-coated iron oxide (Fe3O4/SiO2) magnetic hybrid support. This support combined the both features of Fe3O4 and H PG, facile magnetic separation, and favorable molecular structure with numerous functional groups. With the use of the grafted-HPGs as templates, various noble metal nanocatalysts such as Pt, Au, and Pd were directly grown on the surfaces of magnetic support with ultrasmall and nearly monodisperse sizes (e.g., the average sizes of Pt, Au, and Pd are 4.8 +/- 0.5, 6.0 +/- 0.6, and 4.0 +/- 0.4 nm, respectively) and high coverage densities. Because of the amplification effect of HPG, high loading capacities of the nanocatalysts, around 0.296, 0.243, and 0.268 mmol/g for Pt, Au, and Pd, respectively, were achieved. Representative catalytic reactions including reduction of 4-nitrophenol, alcohol oxidation, and Heck reaction demonstrated the high catalytic activity of the noble metal nanocatalysts. Because of the stabilization of HPG templates, the nanocatalysts can be readily recycled by a magnet and reused for the next reactions with high efficiencies. The robust multifunctional magnetic hybrids will find important applications in catalysis and other fields such as drug delivery and bioseparations.