基于双稳态纳米粒子的静电自组装超晶格的制备与性能研究

Electrostatic self-assembly of nanoparticles (NPs) has been employed as an efficient and versatile approach towards functional system and order superstructures. While great progress has been made, the electrostatic self-assembly of like-charged NPs into superlattice is still quite challenging, particularly in the case of electrostatic assembly without linker, template or spacer molecule. Here, we propose a new approach. By delicate control over the ligand structure, NP size and experimental conditions, interpartcle hydrogen bonding is introduced and the subtle balance between electrostatic interactions, van der Waals interactions and hydrogen bonding can be finely tailored. The overall interparticle interaction features a high potential energy, which enables the bistability of NPs. These bistable NPs form disorder aggregates with controlled size under optimized experimental conditions. Confined by the potential barrier, NPs within the aggregates rearrange into self-assembled superlattices after further inbubation. Theoretical model will be developed to quantify the interactions and potential barrier between NPs and to rationalize the formation of NP superlattices. The structure and physicochemical properties of the as-prepared NP superlattices, as well their applications in chemical sensing, will also be studied.

纳米粒子的静电自组装是一种高效构建功能性体系或规整超结构的通用方法，至今已获长足发展。但在带同种电荷纳米粒子的静电自组装方面，尤其在不借助交联剂、模板或间隔分子的条件下制备带同种电荷纳米粒子的静电自组装超晶格，仍然具有极大的挑战性。对此，本项目提出一种新思路，通过合理设计配体分子结构、纳米粒子尺寸及实验条件，可在纳米粒子之间引入氢键作用，并可精确调控静电作用、范德华作用、氢键作用之间的微妙平衡，从而在纳米粒子之间形成化学势垒，使纳米粒子具有双稳态；然后优化实验条件，制备尺寸可控的纳米粒子无规团聚体，经熟化过程，使团聚中纳米粒子在势垒约束下发生重排，生成自组装超晶格。本项目将建立理论模型，研究双稳态纳米粒子静电自组装过程中的各种相互作用及化学势垒的变化规律，揭示超晶格的形成机理。本项目还将研究该超晶格的结构特性与物理化学性能，并探讨其在高效化学传感器方面的应用。

本项目基于金属-有机框架（MOF）纳米晶体，提出牺牲模板、可控包覆、选择性热解等方法，制备nanoparticle@MOF复合纳米结构，将MOF自身固有的晶态微孔结构与外来引入的大孔相结合，使复合纳米结构在催化反应中同时具有优异的选择性与高效的转化率。系统研究nanoparticle@MOF复合纳米结构的结构调控策略及其生长机理，并将该结构用于纳米反应器与电化学传感器，均表现出优异的性能。本项目还提出简单的一步可控热解方法，实现MOF纳米晶体向金属氧化物纳米颗粒馅饼结构的转变，并研究其结构特征与结构转化机理，将其应用于锂离子电池负极材料，表现出优异的比容量、倍率性能与循环稳定性。本项目为新型nanoparticle@MOF复合纳米结构的发展提供了新的思路，也为在NP@MOF复合纳米结构在选择性催化、传感、能源存储与转化等领域的应用奠定了基础。