Layered double hydroxide (LDH)-based materials: A mini-review on strategies to improve the performance for photocatalytic water splitting

Ultrasound-excited hydrogen radical from NiFe layered double hydroxide for preparation of ultrafine supported Ru nanocatalysts in hydrogen storage of N-ethylcarbazole

“…Layered double hydroxides (LDHs) are a large family of 2D natural and/or synthetic anionic clay materials [19] . The general formula for LDH is [M 2+ (1-x) M 3+ x (OH)]A n- (x/n) ּּּּ·mH 2 O, where M is the metal cation and A is the interlayer anion to compensate for the net positive charge.…”

“…In our previous work, Li et al [33] used two-dimensional layered MgAl-LDH as support, the hydroxyls on the surface of MgAl-LDH were successfully dissociated into the hydrogen radicals under the action of ultrasound without adding any reducing agents and stabilizers to reduce Pd 2+ , thereby obtaining highly dispersed Pd NPs, which showed excellent catalytic performance in Suzuki reaction. However, some studies have indicated that LDH materials composed of transition metals (such as NiFe-LDH) generally showed more attractive catalytic performance due to their different band gap and band edge positions [19] , [34] , [35] .…”

Recent Progress on Transition Metal Based Layered Double Hydroxides Tailored for Oxygen Electrode Reactions

“…Within the 2D structure, LDHs consist of the positively charged host sheets and the interlayer guests containing negatively charged anions and water molecules (Figure 2) [100]. Due to various host-guest assemblies and nanoarchitectures with versatile physico-chemical properties, LDHs have been proved to be promising candidates for a wide range of applications like flame retardant [101], anticorrosive coating [102,103], catalysis [104][105][106], and energy storage and conversion [107][108][109]. Particularly, in the OER electrocatalysis, LDHs offer a number of advantages: (i) the tunable chemical composition, including the type of metal cations and molar ratio of M II /(M II + M III ), favors to improve the intrinsic catalytic activity or introduce the extra active sites; (ii) the exchangeable interlayer anions (A n− ) with large sizes can enlarge the interlayer region, resulting in the exposure of more inner active sites; (iii) the synergistic interaction between the highly dispersed M II and M III cations, in the host sheets, favors the enhancement of the electrocatalytic activity; (iv) the geometric morphology, coordination environment and surface defects of LDHs can be modulated by precisely designing and controlling the chemical compositions of LDHs, which not only provide unsaturated active centers, such as low-coordinated metal cations, corner or edge sites, but also improve the porosity and electronic conductivity; and (v) a series of mixed metal oxides (MMOs) with high electrocatalytic performance can be acquired from LDHs via topological structure transformation process.…”

Layered FeCoNi double hydroxides with tailored surface electronic configurations induced by oxygen and unsaturated metal vacancies for boosting the overall water splitting process

“…38,39 Second, their semiconductor properties with low conductivity can limit the inferior electron transport and cause sluggish kinetics responses. 40,41 Third, inevitable catalyst particle agglomeration and stacking caused by the van der Waals (vdW) interaction can hinder the exposure of reactive sites and lead to the decrease of reactive sites. 42,43 For overcoming these limitations, some modification strategies have been developed for improving the electrocatalytic activity of 2D-LDH materials through enhancing the active site density, improving the intrinsic electrochemical conductivity, and reducing the reaction barrier.…”