Chapter 8 - Layered double hydroxides: An overview of structure-property correlations, synthesis methodologies, and environmental applications

Abstract

The research on two-dimensional (2D) layered materials boosted tremendously after the great discovery of unilamellar graphene. Layered double hydroxides (LDHs) referred to as anionic clays are brucite type of novel 2D layered materials in which metal cations are distributed uniformly and the interplanar space filled with the solvent molecules and anions. LDHs occupied a top place in the environmental applications due to their unusual properties like flexible structure, adjustable composition, high-surface area, easy and eco-friendly synthesis, nontoxicity, high thermal and chemical stability, surface hydroxyl groups, swelling property, biocompatibility, and ability of intercalation. Considering the advantages of LDHs, they are widely used in environmental applications such as organic pollutants and heavy metals removal, production of clean energy (H2), CO2 reduction, and so on. This chapter compiles the fundamental structural aspects of LDHs, their various properties along with the structure-property correlations, synthesis methodologies, and the important techniques to characterize LDHs. Furthermore, this chapter attempts to demonstrate environmental applications of various LDHs and LDHs-based hybrid systems such as removal of pollutants in water bodies, generation of hydrogen fuel, and reduction of CO2 into chemical fuels.