Department of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, P. R. China.
Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States.
J Am Chem Soc. 2021 Dec 1;143(47):19655-19667. doi: 10.1021/jacs.1c05488. Epub 2021 Nov 16.
A variety of inorganic nanoscale materials produce microscale particles with highly corrugated geometries, but the mechanism of their formation remains unknown. Here we found that uniformly sized CdS-based hedgehog particles (HPs) self-assemble from polydisperse nanoparticles (NPs) with diameters of 1.0-4.0 nm. The typical diameters of HPs and spikes are 1770 ± 180 and 28 ± 3 nm, respectively. Depending on the temperature, solvent, and reaction times, the NPs self-assemble into nanorods, nanorod aggregates, low-corrugation particles, and other HP-related particles with complexity indexes ranging from 0 to 23.7. We show that "hedgehog", other geometries, and topologies of highly corrugated particles originate from the thermodynamic preference of polydisperse NPs to attach to the growing nanoscale cluster when electrostatic repulsion competes with van der Waals attraction. Theoretical models and simulations of the self-assembly accounting for the competition of attractive and repulsive interactions in electrolytes accurately describe particle morphology, growth stages, and the spectrum of observed products. When kinetic parameters are included in the models, the formation of corrugated particles with surfaces decorated by nanosheets, known as flower-like particles, were theoretically predicted and experimentally observed. The generality of the proposed mechanism was demonstrated for the formation of mixed HPs via a combination of CdS and CoO NPs. With unusually high dispersion stability of HPs in unfavorable solvents including liquid CO, mechanistic insights into HP formation are essential for their structural adaptation for applications from energy storage, catalysis, water treatment, and others.
多种无机纳米材料产生具有高度波纹状几何形状的微尺度颗粒，但它们的形成机制尚不清楚。在这里，我们发现尺寸均匀的 CdS 基刺猬粒子（HPs）自组装自直径为 1.0-4.0nm 的多分散纳米粒子（NPs）。HPs 和刺的典型直径分别为 1770±180nm 和 28±3nm。根据温度、溶剂和反应时间的不同，NPs 自组装成纳米棒、纳米棒聚集体、低波纹度颗粒和其他具有 0 到 23.7 复杂度指数的与 HP 相关的颗粒。我们表明，“刺猬”、其他几何形状和高度波纹颗粒的拓扑结构源于多分散 NPs 在静电排斥与范德华吸引力竞争时优先附着在生长中的纳米级簇上的热力学偏好。考虑到电解质中吸引力和排斥力竞争的自组装理论模型和模拟准确地描述了颗粒形态、生长阶段和观察到的产物谱。当将动力学参数纳入模型中时，理论上预测并实验观察到表面由纳米片装饰的波纹颗粒的形成，即花状颗粒。通过 CdS 和 CoO NPs 的组合形成混合 HP，证明了所提出的机制的普遍性。由于 HP 在包括液体 CO 在内的不利溶剂中的分散稳定性异常高，因此了解 HP 的形成机制对于它们在储能、催化、水处理等应用中的结构适应性至关重要。
