Recent Advances in the Synthesis of Layered, Double‐Hydroxide‐Based Materials and Their Applications in Hydrogen and Oxygen Evolution

Abstract

Layered double hydroxides (LDHs) consist of brucite‐like layers containing hydroxides of two or more different kinds of metal cations. These positively charged layers are neutralized by exchangeable anions in the interlayer galleries. LDH‐based materials have substantial potential in efficient energy (e.g., H2, O2) generation. Over the last few decades, tremendous progress has been made toward developing LDH‐based materials for H2 and O2 evolution, for which the performance of LDH‐based materials is closely related to the synthesis method. This minireview initially outlines the recent advances in the synthesis of LDH‐based materials. The advantages and challenges of the protocols in tuning the properties of the material are also discussed and highlighted. The application section concentrates on the most recent progress in photocatalytic H2 generation and photocatalytic and electrocatalytic O2 evolution. By taking advantage of the flexible tunability and uniform distribution of metal cations in the brucite‐like layers or the intercalated anions in the interlayer space, LDH‐based materials exhibit attractive properties in the generation of H2 and O2 with advantages such as improved light absorption, enhanced charge separation, better electron transfer, promoted electrode reaction kinetics, and high durability.

Layered Double Hydroxides: Tailoring Interlamellar Nanospace for a Vast Field of Applications

“…The structure of an ideal Layered Double Hydroxide is based on M(OH) 6 edge-sharing octahedral units forming coplanar brucite-like layers (lamellas) which are stacked on top of one another to form a 3D structures [3][4][5][6][7], as schematically shown in Figure 1. Differently from brucite, which is only formed by neutral magnesium hydroxide, LDH sheets acquire a net positive charge due to the substitution of a certain fraction x of the divalent cations M 2+ with the trivalent ones M…”

“…LDH-like structure has also been attributed to Li-Al monovalent/trivalent and to Co-Ti divalent/tetravalent couples [3][4][5][6][7]. These lists show that the lattice stability also requires the ionic radius to lie in the range 0.50-0.74 Å. LDHs have also been prepared with more than two different metallic cations, which give the chance of further variations of the chemical/ physical properties.…”

“…phase purity, crystallinity, porosity, morphology, and electronic and optical characteristics [3][4][5][6][7]. The different methods can be schematically grouped in two main classes: direct methods and indirect ones.…”

“…drug delivery and biosensors) [7,8], and in many other fields. Furthermore, by using transition metals as the component cations, they have been suggested as promising materials in energy harvesting and conversion [9].…”

Benzoate Anion‐Intercalated Layered Cobalt Hydroxide Nanoarray: An Efficient Electrocatalyst for the Oxygen Evolution Reaction

“…[9] The dense and uniform distribution of catalytic metal sites in the octahedral sheets, as well as the exchangeability of interlayer anions, make LMHs promising for electrochemical applications, [10] and extensive research has been performed to explore electroactive materials based on LMHs. [9] The dense and uniform distribution of catalytic metal sites in the octahedral sheets, as well as the exchangeability of interlayer anions, make LMHs promising for electrochemical applications, [10] and extensive research has been performed to explore electroactive materials based on LMHs.…”