Search results for "Layered Double Hydroxide"
showing 10 items of 47 documents
Emerging switchable ultraviolet photoluminescence in dehydrated Zn/Al layered double hydroxide nanoplatelets
2019
AbstractLayered double hydroxides show intriguing physical and chemical properties arising by their intrinsic self-assembled stacking of molecular-thick 2D nanosheets, enhanced active surface area, hosting of guest species by intercalation and anion exchanging capabilities. Here, we report on the unprecedented emerging intense ultraviolet photoluminescence in Zn/Al layered double hydroxide high-aspect-ratio nanoplatelets, which we discovered to be fully activated by drying under vacuum condition and thermal desorption as well. Photoluminescence and its quenching were reproducibly switched by a dehydration–hydration process. Photoluminescence properties were comprehensively evaluated, such a…
Specific separation and recovery of phosphate anions by a novel NiFe-LDH/rGO hybrid film based on electroactivity-variable valence
2022
Phosphorus is a non-renewable resource. Supplies are limited and much phosphorus is currently wasted during the production and utilization process, causing concerns about future supplies and widespread environmental problems. To solve these problems, a new type of NiFe-LDH/rGO electrically switched ion-selective (ESIX) film is designed, based on the dominant mechanism of inner-sphere complexation. An ESIX process allows the NiFe-LDH/rGO hybrid film to achieve a controllably selective uptake and release of the phosphate anions. This route involves tuning potential steps to regulate the redox states of the composite film and the variable metal (e.g., Ni, Fe (II)/(III)) in coordination centers…
2020 Roadmap on two-dimensional nanomaterials for environmental catalysis
2019
Abstract Environmental catalysis has drawn a great deal of attention due to its clean ways to produce useful chemicals or carry out some chemical processes. Photocatalysis and electrocatalysis play important roles in these fields. They can decompose and remove organic pollutants from the aqueous environment, and prepare some fine chemicals. Moreover, they also can carry out some important reactions, such as O2 reduction reaction (ORR), O2 evolution reaction (OER), H2 evolution reaction (HER), CO2 reduction reaction (CO2RR), and N2 fixation (NRR). For catalytic reactions, it is the key to develop high-performance catalysts to meet the demand for targeted reactions. In recent years, two-dimen…
Hybrid Materials Based on Magnetic Layered Double Hydroxides: A Molecular Perspective
2015
Design of functional hybrids lies at the very core of synthetic chemistry as it has enabled the development of an unlimited number of solids displaying unprecedented or even improved properties built upon the association at the molecular level of quite disparate components by chemical design. Multifunctional hybrids are a particularly appealing case among hybrid organic/inorganic materials. Here, chemical knowledge is used to deploy molecular components bearing different functionalities within a single solid so that these properties can coexist or event interact leading to unprecedented phenomena. From a molecular perspective, this can be done either by controlled assembly of organic/inorga…
Interplay between Chemical Composition and Cation Ordering in the Magnetism of Ni/Fe Layered Double Hydroxides
2013
We report the synthesis of a family of ferrimagnetic NiFe layered double hydroxides (LDHs) with a variable Ni(2+)/Fe(3+) in-plane composition of [Ni(1-x)Fe(x)(OH)2](CO3)(x/2)·yH2O (x = 0.20, 0.25, and 0.33) by following a modified homogeneous precipitation. These layered magnets display high crystallinity, homogeneous hexagonal morphologies, and micrometric size that enable their quantitative exfoliation into single layers by sonomechanical treatment of the solids in polar solvents. This was confirmed by dynamic light scattering, UV-vis spectroscopy, high-resolution transmission electron miscroscopy, and atomic force microscopy methodologies to study the resulting steady suspensions. Our ma…
Room Temperature Magnetism in Layered Double Hydroxides due to Magnetic Nanoparticles
2013
Some recent reports claiming room temperature spontaneous magnetization in layered double hydroxides (LDHs) have been published; however, the reported materials cause serious concern as to whether this cooperative magnetic behavior comes from extrinsic sources, such as spinel iron oxide nanoparticles. The syntheses of crystalline Fe(3+)-based LDHs with and without impurities have been developed, highlighting the care that must be taken during the synthetic process in order to avoid misidentification of magnetic LDHs.
Deciphering the Role of Dipolar Interactions in Magnetic Layered Double Hydroxides
2018
Layered double hydroxides (LDHs) exhibit unparalleled anion exchange properties and the ability to be exfoliated into 2D nanosheets, which can be used as a building block to fabricate a wide variety of hybrid functional nanostructured materials. Still, if one wants to use LDHs as a magnetic building blocks in the design of complex architectures, the role played by the dipolar magnetic interactions in these layered materials needs to be understood. In this work, we synthesized and characterized a five-membered CoAl-LDH series with basal spacing ranging from 7.5 to 34 Å. A detailed experimental characterization allows us to conclude that the main factor governing the dipolar interactions betw…
Cover Feature: Fundamental Insights into the Covalent Silane Functionalization of NiFe Layered Double Hydroxides (Chem. Eur. J. 29/2020)
2020
Layered Double Hydroxides
2020
The impact of layered double hydroxides (LDHs) within the multidisciplinary fields of materials sciences, physics, chemistry, and biology is rapidly growing, given their easiness of synthesis, flexibility in composition, tunable biocompatibility and morphology. LDHs constitute a versatile platform for the realization of new classes of functional systems, showing unique enhanced surface effects and unprecedented properties for application in very different fields, namely, surface chemistry and catalysis, storage and triggered release of functional anions, flame retardants, drug delivery and nanomedicine, remediation, energy storage and conversion. These systems can be synthesized as self-ass…
Zn,Al hydrotalcites calcined at different temperatures: Preparation, characterization and photocatalytic activity in gas–solid regime
2011
Abstract Layered double hydroxides (LDH) containing zinc and aluminium within the brucite-like layers and carbonate as the interlayer anion have been used as precursors for the preparation of mixed metal oxides by calcination. Zinc oxide and the ZnAl 2 O 4 spinel were formed with different degree of crystallinity depending of two parameters, i.e., the Zn 2+ /Al 3+ molar ratio and the calcination temperature (500–800 °C) of the LDH precursor. A pure spinel phase was obtained to remove ZnO upon a basic post-treatment in NaOH solution of the samples calcined at 800 °C. All the samples were tested for the photodegradation of 2-propanol in gas–solid regime. All the samples resulted active as het…