Why Do Carbonate Anions Have Extremely High Stability in the Interlayer Space of Layered Double Hydroxides? Case Study of Layered Double Hydroxide Consisting of Mg and Al (Mg/Al = 2)

Abstract

Layered double hydroxides (LDHs) are promising compounds in a wide range of fields. However, exchange of CO 3 2− anions with other anions is necessary, because the CO 3 2− anions are strongly affixed in the LDH interlayer space. To elucidate the reason for the extremely high stability of CO 3 2− anions intercalated in LDHs, we investigated in detail the chemical states of CO 3 2− anions and hydrated water molecules in the LDH interlayer space by synchrotron radiation X-ray diffraction, solid-state NMR spectroscopy, and Raman spectroscopy. We found the rigidity of the network structure formed between the CO 3 2− anions, hydrated water molecules, and the hydroxyl groups on the metal hydroxide layer surface to be a crucial factor underlying the stability of CO 3 2− anions in the LDH interlayer space.

Layered double hydroxide-based electrocatalysts for the oxygen evolution reaction: identification and tailoring of active sites, and superaerophobic nanoarray electrode assembly

“…He has over 170 publications and his research contributed to 2 high tech spin-offs. topotactic derivatives 94,95 have been documented to exhibit outstanding performance towards the OER, originating from their highly controllable structure, [96][97][98] intensive host-guest interactions [99][100][101] and highly dispersed single-atomic sites. 102 There are already several review articles which have summarized the development of LDHs for the OER from material and characterization perspectives.…”

Important Roles of Water Clusters Confined in a Nanospace as Revealed by a Synchrotron X-ray Diffraction Study

“…The interlayer expansion during the caffeine intercalation was kinetically evaluated in a t-SXRD measurement system developed at the BL02B2 beamline facility in SPring-8 as described in the literature (see the Supporting Information, Figure S1). 47 The system comprises a diffractometer equipped with a sample stage, an autotitrator (Dosimat plus, Metrohm AG), and a multiple MYTHEN detector. The sample stage was equipped with a glass tube holder (a 10 mm diameter aluminum block), a water-cooling jacket, and a magnetic stirrer.…”

Efficient, scalable, closed-loop synthesis of highly crystalline pure phase MgAl-layered double hydroxides intercalated with hydroxyl anions

“…Moreover, the MgAl-LDH obtained via the homogeneous precipitation method usually has a Mg/Al ratio equal to or less than two, 19,20 which can limit severely the performance of MgAl-LDH in a number of applications, such as catalysis, 21 adsorption, 8 and ion exchange. 22 To tackle the drawbacks of coprecipitation and homogeneous precipitation, various modified and new methods have been proposed. Zhao, et al 23 devised a method that separates nucleation and aging into two distinct steps in the LDH preparation.…”