分级结构纳米材料的液相合成策略

由于具有多层次、多维度、多组分的耦合和协同效应,分级结构纳米材料的设计合成近年来吸引了广泛的关注.本文从分级结构的三种实现方式,即核壳结构、节型结构和分支结构,分别介绍其液相合成方法进展,并侧重从晶体成核生长和反应动力学等角度对分级结构的形成原理和影响因素进行阐述.总的来说,分级结构材料的构筑主要涉及次级结构材料在初级结构材料上的异质成核生长或两种材料之间的成分交换.其中,材料之间的晶格匹配度、次级结构材料的过饱和度及化学成键情况等是影响二次相成核位点及方式的重要因素,而对晶面能的调控是调节二次相材料生长行为的重要途径.对基于成分交换的合成策略来讲,一个重要的前提条件是两种材料具有相同的阴离子或阳离子.

Solution Synthesis Strategies for Hierarchical Nanostructures

The coupling and synergistic effects of the unique structure of multi-level, multi-dimension, and multi- components allow for the directed synthesis of hierarchical nanostructures and this field has attracted much interest recently. In this paper, we discuss progress in the solution synthesis of three kinds of hierarchical structures including core-shell, segmented, and branched structures. We focus on the formation mechanism and the influencing factors of the hierarchical structures by considering the crystal nucleation-growth process and growth kinetics. The construction of the hierarchical nanocomposites mainly involves the heterogeneous nucleation-growth of the secondary structures on the primary structures or a component exchange between the two kinds of materials. The degree of lattice matching, the degree of supersaturation, and chemical bonding mainly influence the hetero-nucleation sites of the secondary structures on the primary structures. The growth behaviors of the secondary structures can be modulated mainly by adjusting their crystallographic energy through surface modifications. For the synthesis via component exchange, an important prerequisite is that the primary and secondary structures share the same anions or cations.