Reconstruction and intercalating anion exchange of ZnAl-layered double hydroxide

Abstract

Layered double hydroxides (LDHs) have recently attracted considerable attention as a promising multi-functional material due to their controllable properties depending on the type and composition ratio of metal cations and interlayer anions. Despite active research on controlling the composition to improve the properties of LDHs, anion intercalation techniques capable of obtaining the desired morphologies of LDHs have rarely been investigated. Herein, we report the anion exchange of ZnAl-LDHs grown on a silicon substrate using a post-treatment-based reconstruction process. Structural and chemical investigations verified that the calcined ZnAl-LDH was reconstructed by a NaCl solution during the anion exchange process. The anion exchange rate and the reconstructed fraction of the ZnAl-LDH increased as the NaCl concentration increased from 0.15 M to 0.60 M, though they decreased when the NaCl concentration exceeded 0.90 M. Therefore, the anion composition and morphology of the ZnAl-LDHs could be modulated by controlling the NaCl concentration during the reconstruction process. These results provide important information about the probability of controlling the structure and composition of LDHs intercalated with desired anions for a wide variety of device applications, such as memory, sensor, and energy storage.