Delamination and restacking of a layered double hydroxide with nitrate as counter anion

Abstract

A layered double hydroxide (LDH) with nitrate as the counter anion (LDH-NO 3 with Mg/Al = 3) was, for the first time, successfully delaminated in formamide under ultrasonic treatment. Atomic force microscopy (AFM) images showed that a large part of the LDH was delaminated into single and double brucite layers (0.7-1.4 nm in thickness). The nano-sheets had disk-like shapes with a diameter of ca. 20-40 nm. Findings from AFM were in good agreement with the average hydrodynamic diameter determined using dynamic light scattering. Powder X-ray diffraction pattern of LDH dispersed in formamide also confirmed that LDH-NO 3 was exfoliated. The dispersions of LDH in formamide were stable and transparent up to a concentration of 40 g L 21 . However, formation of transparent gels was observed at concentrations higher than 5 g L 21 . Delaminated LDH could be restacked by adding sodium carbonate or ethanol.

Large-scale self-assembled zirconium phosphate smectic layers via a simple spray-coating process

“…The intercalation of such ionic species into the inter-layers weakens the inter-layer binding and promotes exfoliation of the layered structures into individual 2D crystals. Liquid exfoliation using similar intercalation methods have been demonstrated in a broad family of layered functional materials such as transition metal oxides 20 and dichalcogenides 21 , layered double hydroxides 22 , h-BN 23 and even graphene 24,25 . Thus, it is suggested that liquid exfoliation via surface functionalization using oligomeric compounds is a general method, and the phenomenon observed here should be applicable to these other layered materials with the proper selection of compatible functionalizing species and solvent.…”

Co—Fe Prussian Blue Analogue Intercalated into Diamagnetic Mg—Al Layered Double Hydroxides

“…The absorption peak at 1,380 cm -1 was observed in LDH-NO 3 , which is attributable to the symmetric vibration of the interlayer nitrate anion (Figure 1Ba). [28][29][30][31]36] LDH-Fe(CN) 6 showed that an absorption peak at 1,380 cm [25,37,38] SEM images of the LDH-NO 3 and LDH-Fe(CN) 6 are shown in Figure 1C. As can be seen, the rosette aggregation for LDH-NO 3 was observed (Figure 1Ca).…”

Reactivity and applications of layered silicates and layered double hydroxides

“…In formamide some LDH dispersions were stable and transparent up to a concentration of 40 g l −1 , but formation of transparent gels was observed at concentrations higher than 5 g l −1 . 231 The delaminated LDHs could be restacked by adding sodium carbonate or ethanol. 231 Li et al 232 delaminated large crystals (10 µm) of Mg/Al LDH with a nitrate as the interlayer anion by simple shaking for 12 h in formamide.…”

“…231 The delaminated LDHs could be restacked by adding sodium carbonate or ethanol. 231 Li et al 232 delaminated large crystals (10 µm) of Mg/Al LDH with a nitrate as the interlayer anion by simple shaking for 12 h in formamide. As one application example the obtained dispersion was subsequently used for a layer-by-layer selfassembly of the LDH nanosheets and anionic polymers to produce multilayer nanocomposite films.…”