Porous Layered Double Hydroxides Synthesized using Oxygen Generated by Decomposition of Hydrogen Peroxide

Abstract

Porous magnesium-aluminium layered double hydroxides (LDH) were prepared through intercalation and decomposition of hydrogen peroxide (H2O2). This process generates oxygen gas nano-bubbles that pierce holes in the layered structure of the material by local pressure build-up. The decomposition of the peroxide can be triggered by microwave radiation or chemically by reaction with iodide (I−) ions. The carbonate LDH version [Mg0.80Al0.20(OH)2](CO3)0.1∙mH2O was synthesized by microwave-assisted urea coprecipitation and further modified by iodide or H2O2 intercalation. High resolution Scanning Electron Microscopy (HR-SEM) and Brunauer-Emmet-Teller (BET) analysis were used to assess the morphology and surface area of the new porous materials. The presence of H2O2 in the interlayer region and later decomposition triggered by microwave radiation generated more pores on the surface of the LDH platelets, increasing their specific surface area from initially 9 m2/g to a maximum of 67 m2/g. X-Ray Diffraction showed that the formation of the pores did not affect the remaining crystal structure, allowing possible further functionalization of the material.

Crystalline Ammonium Peroxogermanate as a Waste-Free, Fully Recyclable Versatile Precursor for Germanium Compounds

“…Coordination of metal and metalloid precursors and capping of nanoparticles are two interconnected means to control the morphology and structure of nanomaterials. Hydrogen peroxide is gradually recognized as an efficient modifier for advanced nanomaterials. − Unlike most coordination agents, peroxide can be easily eliminated from the end product by thermal decomposition. Its removal does not involve solvent extraction or high temperature processing, thereby reducing or eliminating the waste problem.…”

Alkali-Free Hydrothermally Reconstructed NiAl Layered Double Hydroxides for Catalytic Transesterification

“…Calcined NiAl and ZnAl LDHs are reported as inactive for sunflower oil transesterification with methanol at 65 • C [50]. Our reconstructed Ni 4.1 Al LDH, which affords 14% trilaurin conversion (albeit at a higher temperature), is promising, despite their essentially microporous nature arising from a lamellar structure [59] with layer spacing of 0.3 nm observed in HRTEM (Figure S4), which hinders access of bulky TAGs to interlayers and in-pore base sites. Hence, most TAG activation is expected to occur over the external surface of the 2D NiAl LDH lamellar sheets in the sand rose structure observed in Figure 2c.…”

Development of Mesopore Structure of Mixed Metal Oxide through Albumin-Templated Coprecipitation and Reconstruction of Layered Double Hydroxide

“…The metal oxide domains produced during thermal treatment can be connected by the trivalent metals migrated to tetrahedral site [ 23 , 24 ], resulting in intra-particle mesopores [ 25 , 26 , 27 ]. It is generally known that LDHs prepared by conventional coprecipitation method tend to have specific surface area (S BET ) around 20–60 m 2 /g [ 28 , 29 , 30 ], while the corresponding LDO had S BET higher than 100 m 2 /g [ 27 , 30 ].…”