Hydrothermal Synthesis and Formation Mechanism of Self-Assembled Strings of CoOOH Nanodiscs

The formation and self-assembly mechanisms of nanoma-terials are of great significance for the preparation and application of materials. In this study, the orientationally aggregated CoOOH nanosheets and the self-assembled strings of CoOOH nanodiscs were prepared by hydrothermal method. The formation and self-assembly mechanisms of CoOOH nanodiscs were investigated by XRD, XPS, DLS, TEM, and SEM techniques, as well as DFT calculations. The results show that the formation process of the stacked CoOOH nanodiscs was driven by surface energy and can be divided into four steps: nucleation and growth of CoOOH primary nanosheets; oriented attachment of CoOOH nanosheets; self-assembly of CoOOH nanodiscs; and aggregation of strings of CoOOH nanodiscs. This study contributes meaningfully to the controllable preparation of CoOOH nanomaterials.