Yu Huan, Zhu Yang, Yang Hui, Nakanishi Kazuki, Kanamori Kazuyoshi, Guo Xingzhong
Department of Materials Science and Engineering, Zhejiang University, Hangzhou, China.
Dalton Trans. 2014 Sep 7;43(33):12648-56. doi: 10.1039/c4dt00655k.
A facile and "green" method was proposed to introduce Ag nanoparticles (Ag NPs) into the hierarchically monolithic silica uniformly in the presence of (3-aminopropyl)-triethoxysilane (APTES) and ethylene glycol. APTES is used to modify the monolith by incorporating amino groups onto the surface of meso-macroporous skeletons, while ethylene glycol is employed as the productive reductant. Ag NPs are homogeneously immobilized in hierarchically monolithic silica after reduction and drying at 40 °C for different duration times, and the embedded amount of Ag NPs can reach 15.44 wt% when treated once. The embedment of Ag NPs increases with the repeat treatment and the APTES amount, without uncontrollable crystalline growth. The surface areas of Ag NPs embedded in silica monoliths after heat treatment at 300 and 400 °C are higher than those before heat treatment. The modification via APTES and the embedment of Ag NPs does not spoil the morphology of monolithic silica, while changing the pore structures of the monolith. A tentative formation process and a reduction mechanism are proposed for the modification, reduction and embedment. Ag NPs embedded in monolithic silica is promising for wide applications such as catalysis and separation.
提出了一种简便的“绿色”方法，在（3-氨丙基）三乙氧基硅烷（APTES）和乙二醇存在下，将银纳米颗粒（Ag NPs）均匀引入分级整体式二氧化硅中。APTES用于通过将氨基结合到介孔-大孔骨架表面来修饰整体材料，而乙二醇用作生产性还原剂。在40℃下还原并干燥不同持续时间后，Ag NPs均匀固定在分级整体式二氧化硅中，单次处理时Ag NPs的嵌入量可达15.44 wt%。Ag NPs的嵌入量随着重复处理次数和APTES用量的增加而增加，且无不可控的晶体生长。在300℃和400℃热处理后，嵌入二氧化硅整体材料中的Ag NPs的表面积高于热处理前。通过APTES进行的修饰和Ag NPs的嵌入不会破坏整体式二氧化硅的形态，同时会改变整体材料的孔结构。针对修饰、还原和嵌入过程提出了一个初步的形成过程和还原机制。嵌入整体式二氧化硅中的Ag NPs在催化和分离等广泛应用中具有广阔前景。
