Recent Advance of Transition‐Metal‐Based Layered Double Hydroxide Nanosheets: Synthesis, Properties, Modification, and Electrocatalytic Applications

Abstract

Nowadays, to alleviate the growing pressure of energy shortages and environmental pollution, electrochemical energy conversion is seen as a fossil‐free, secondary pollution‐free, and highly efficiency pathway. Electrocatalysts, as the “heart” of the electrochemical conversion process, play a key role in accelerating reaction rates and promoting efficiency. Transition‐metal‐based layered double hydroxides (TM LDHs), one of the famous electrocatalysts, show unique 2D supermolecular‐stratified structure, excellent electronic properties, and their raw materials are easily available. In this review, electrocatalysis‐related properties of TM LDHs and the state‐of‐the‐art synthesis methods of TM LDH‐based electrocatalysts are summarized. Modifications for promoting the development of TM LDH‐based electrocatalysts are included, such as carbon materials modification, defect engineering, and noble metal loading. Then, the application of TM LDH nanosheets in the field of electrocatalysis is reviewed in detail. Finally, recent challenges, ongoing improvements, and future expectations for TM LDH nanosheets are presented.

Synthesis and Electronic Modulation of Nanostructured Layered Double Hydroxides for Efficient Electrochemical Oxygen Evolution

“…Therefore, monometallic hydroxides would be converted into positively charged Ni 3+ ‐doped nickel hydroxide or Co 3+ ‐doped cobalt hydroxide in conventional conditions [62] . Even though plentiful researches have been done on monometallic nickel hydroxide or cobalt hydroxide‐based nLDHs, their catalytic activities for OER were not satisfactory [63] . Introducing metallic dopants with tailored valence state into monometallic hydroxides is a useful way to improve the intrinsic OER activity due to π‐electron redistribution by O 2− (an oxygen bridge between metals) and gives excellent desorption/adsorption of oxygen species [64] .…”

Transition Metal-Based 2D Layered Double Hydroxide Nanosheets: Design Strategies and Applications in Oxygen Evolution Reaction

“…They proposed that CeOx is permselective to the mobility of OH − and O 2 , preventing the diffusion of redox ions and enhancing its stability. Furthermore, the stability of TM-LDHs can also be improved by growing TM-LDHs directly on 3D electrode materials, which reduce the loss of active sites [ 26 ]. Yang et al designed a 3D hierarchical CoFe-LDH@NiFe-LDH supported on nickel foam, demonstrating outstanding stability as an OER catalyst under alkaline conditions [ 139 ].…”

“…Owing to their higher abundance, low cost, and environmental friendliness, TMs, and their oxides [ 22 ], hydroxides [ 23 ], chalcogenides [ 24 ], and phosphides [ 25 ], have shown potential applications as OER catalyst alternative to precious metals. Among various nonprecious metal-based OER electrocatalysts that have been studied so far, transition metal layered double hydroxides (TM-LDHs) with two-dimensional (2D) structures have invoked a lot of attention lately [ 26 , 27 ].…”

Bi‐Functional Fe3O4/Au/CoFe‐LDH Sandwich‐Structured Electrocatalyst for Asymmetrical Electrolyzer with Low Operation Voltage

“…), large surface area, [ 15 ] and easy functionalization with other materials. [ 16 ] As a result, it is widely used for oxygen evolution electrocatalysis, [ 17 ] supercapacitors, [ 18 ] and hydrogen evolution electrocatalysis. [ 19 ] Nevertheless, the stability of LDH in alkaline HER is not satisfactory, where the high‐valence metal elements are easily reduced.…”