Controllable synthesis of layered double hydroxides: From macroscopic morphology to microscopic coordination at the atomic level

Layered double hydroxides (LDHs), as a typical inorganic two-dimensional layered material, have been widely studied in the fields of photoelectrocatalysis, energy, and environment due to their unique layered structure and excellent catalytic activity. In addition, the flexible and adjustable laminate composition of LDHs, the flexible anion exchange and column-supported exfoliation of the domain-limited space allow the reactivity of LDHs to be modulated with the changes in their composition, size, thickness, morphology, etc. Therefore, the precise synthesis of LDHs from macroscopic to microscopic is the key to promoting their development in fundamental science and industrial application. Herein, we summarize the controllable synthesis methods of LDHs in recent years, including the precise tuning strategies of macroscopic structure, such as morphology, size, thickness, etc. Furthermore, controllable preparation strategies of coordination structure at the atomic level, including the intercalation ions, coordination number, and coordination environment were also reviewed. Meanwhile, the application of synthesized LDHs with specific structures in photocatalysis, batteries, environment, and other fields has also been mentioned. Finally, the major challenges and prospects of LDHs are discussed in terms of further improving the controllability of precise synthesis.