The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Xue Duan - One of the best experts on this subject based on the ideXlab platform.
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ternary nifemn Layered Double Hydroxides as highly efficient oxygen evolution catalysts
Chemical Communications, 2016Co-Authors: Li Qian, Yang Tian, Xiaoming Sun, Xue DuanAbstract:Layered Double Hydroxides (LDHs) are a family of layer materials that receive heightened attention. Herein a ternary NiFeMn-LDH is investigated with superior oxygen evolution activity, which is attributed to the Mn4+ doping in the intralayer, which modifies the electronic structure and improves the conductivity of the electrocatalyst.
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Layered Double Hydroxides toward electrochemical energy storage and conversion design synthesis and applications
Chemical Communications, 2015Co-Authors: Mingfei Shao, David G. Evans, Min Wei, Ruikang Zhang, Xue DuanAbstract:Two-dimensional (2D) materials have attracted increasing interest in electrochemical energy storage and conversion. As typical 2D materials, Layered Double Hydroxides (LDHs) display large potential in this area due to the facile tunability of their composition, structure and morphology. Various preparation strategies, including in situ growth, electrodeposition and layer-by-layer (LBL) assembly, have been developed to directly modify electrodes by using LDH materials. Moreover, several composite materials based on LDHs and conductive matrices have also been rationally designed and employed in supercapacitors, batteries and electrocatalysis with largely enhanced performances. This feature article summarizes the latest developments in the design, preparation and evaluation of LDH materials toward electrochemical energy storage and conversion.
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niti Layered Double Hydroxides nanosheets as efficient photocatalysts for oxygen evolution from water using visible light
Chemical Science, 2014Co-Authors: David G. Evans, Xue Duan, Yufei Zhao, Min Wei, Qiang Wang, Wa Gao, Chengle J Wang, Dermot OhareAbstract:NiTi-Layered Double Hydroxides (LDH) nanosheets with lateral dimensions in the range 30–60 nm have been prepared using a reverse microemulsion method. These materials exhibit excellent photocatalytic activity (∼2148 μmol g−1 h−1) for oxygen evolution from water using visible light. The quantum yield was found to be 65.0% and 20.0% using monochromatic irradiation at 400 and 650 nm respectively.
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Catalytic applications of Layered Double Hydroxides: Recent advances and perspectives
Chemical Society Reviews, 2014Co-Authors: Guoli Fan, Longlong Lianyang Zhang, Sònia Abelló, Saurabh Dhir, Gisela Colet, Daishe Wu, Tianqi Wang, Javier Pérez-ramírez, David G. Evans, Xue Duan, Feng Li, Ray L. Frost, Ping Zhang, Francisco MedinaAbstract:This review surveys recent advances in the applications of Layered Double Hydroxides (LDHs) in heterogeneous catalysis. By virtue of the flexible tunability and uniform distribution of metal cations in the brucite-like layers and the facile exchangeability of intercalated anions, LDHs-both as directly prepared or after thermal treatment and/or reduction-have found many applications as stable and recyclable heterogeneous catalysts or catalyst supports for a variety of reactions with high industrial and academic importance. A major challenge in this rapidly growing field is to simultaneously improve the activity, selectivity and stability of these LDH-based materials by developing ways of tailoring the electronic structure of the catalysts and supports. Therefore, this Review article is mainly focused on the most recent developments in smart design strategies for LDH materials and the potential catalytic applications of the resulting materials.
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hierarchical films of Layered Double Hydroxides by using a sol gel process and their high adaptability in water treatment
Chemical Communications, 2010Co-Authors: Yufei Zhao, David G. Evans, Min Wei, Xue DuanAbstract:Layered Double Hydroxides (LDHs) films with hierarchical morphologies have been fabricated on different templates via the sol–gel nanocopying and in situ growth process, which exhibit desirable mechanical properties and high adaptability in water treatment.
Baoliang Chen - One of the best experts on this subject based on the ideXlab platform.
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perchlorate uptake and molecular mechanisms by magnesium aluminum carbonate Layered Double Hydroxides and the calcined Layered Double Hydroxides
Chemical Engineering Journal, 2014Co-Authors: Qile Fang, Baoliang ChenAbstract:Abstract A series of Mg/Al carbonate Layered Double Hydroxides (LDHs) with different Mg/Al ratios and their calcined LDHs (CLDHs) were prepared as a promising adsorbent of perchlorate anionic pollutant. The LDHs, CLDHs and reconstructed LDHs were characterized by X-ray diffraction, SEM, Raman and FTIR spectra. The adsorption of perchlorate to the parent LDHs was very weak, and the isotherms fit well to the Freundlich model. The perchlorate uptake was independent of the positive charge density of the hydroxide layers because the interlayer carbonate was not significantly replaced by perchlorate. In contrast, the CLDHs exhibited a high adsorption capacity with a nonlinear isotherm, which was mainly driven by the structural memory effect of the LDHs with perchlorate as an interlayer anion. The perchlorate uptake by the CLDHs was enhanced as the positive layer charge density decreased, which cannot be explained by anion exchange mechanism alone. According to the Cl–O and O–H stretching vibrations of the reconstructed ClO 4 - -LDHs, we proposed that perchlorate transfer a negative charge to positively hydroxide layers via electrostatic interactions, then the oxygen atoms of perchlorate are polarized by the surrounding hydroxyls and form strong hydrogen bonds with the hydroxide layers.
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perchlorate uptake and molecular mechanisms by magnesium aluminum carbonate Layered Double Hydroxides and the calcined Layered Double Hydroxides
Chemical Engineering Journal, 2014Co-Authors: Qile Fang, Baoliang ChenAbstract:Abstract A series of Mg/Al carbonate Layered Double Hydroxides (LDHs) with different Mg/Al ratios and their calcined LDHs (CLDHs) were prepared as a promising adsorbent of perchlorate anionic pollutant. The LDHs, CLDHs and reconstructed LDHs were characterized by X-ray diffraction, SEM, Raman and FTIR spectra. The adsorption of perchlorate to the parent LDHs was very weak, and the isotherms fit well to the Freundlich model. The perchlorate uptake was independent of the positive charge density of the hydroxide layers because the interlayer carbonate was not significantly replaced by perchlorate. In contrast, the CLDHs exhibited a high adsorption capacity with a nonlinear isotherm, which was mainly driven by the structural memory effect of the LDHs with perchlorate as an interlayer anion. The perchlorate uptake by the CLDHs was enhanced as the positive layer charge density decreased, which cannot be explained by anion exchange mechanism alone. According to the Cl–O and O–H stretching vibrations of the reconstructed ClO 4 - -LDHs, we proposed that perchlorate transfer a negative charge to positively hydroxide layers via electrostatic interactions, then the oxygen atoms of perchlorate are polarized by the surrounding hydroxyls and form strong hydrogen bonds with the hydroxide layers.
Qile Fang - One of the best experts on this subject based on the ideXlab platform.
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perchlorate uptake and molecular mechanisms by magnesium aluminum carbonate Layered Double Hydroxides and the calcined Layered Double Hydroxides
Chemical Engineering Journal, 2014Co-Authors: Qile Fang, Baoliang ChenAbstract:Abstract A series of Mg/Al carbonate Layered Double Hydroxides (LDHs) with different Mg/Al ratios and their calcined LDHs (CLDHs) were prepared as a promising adsorbent of perchlorate anionic pollutant. The LDHs, CLDHs and reconstructed LDHs were characterized by X-ray diffraction, SEM, Raman and FTIR spectra. The adsorption of perchlorate to the parent LDHs was very weak, and the isotherms fit well to the Freundlich model. The perchlorate uptake was independent of the positive charge density of the hydroxide layers because the interlayer carbonate was not significantly replaced by perchlorate. In contrast, the CLDHs exhibited a high adsorption capacity with a nonlinear isotherm, which was mainly driven by the structural memory effect of the LDHs with perchlorate as an interlayer anion. The perchlorate uptake by the CLDHs was enhanced as the positive layer charge density decreased, which cannot be explained by anion exchange mechanism alone. According to the Cl–O and O–H stretching vibrations of the reconstructed ClO 4 - -LDHs, we proposed that perchlorate transfer a negative charge to positively hydroxide layers via electrostatic interactions, then the oxygen atoms of perchlorate are polarized by the surrounding hydroxyls and form strong hydrogen bonds with the hydroxide layers.
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perchlorate uptake and molecular mechanisms by magnesium aluminum carbonate Layered Double Hydroxides and the calcined Layered Double Hydroxides
Chemical Engineering Journal, 2014Co-Authors: Qile Fang, Baoliang ChenAbstract:Abstract A series of Mg/Al carbonate Layered Double Hydroxides (LDHs) with different Mg/Al ratios and their calcined LDHs (CLDHs) were prepared as a promising adsorbent of perchlorate anionic pollutant. The LDHs, CLDHs and reconstructed LDHs were characterized by X-ray diffraction, SEM, Raman and FTIR spectra. The adsorption of perchlorate to the parent LDHs was very weak, and the isotherms fit well to the Freundlich model. The perchlorate uptake was independent of the positive charge density of the hydroxide layers because the interlayer carbonate was not significantly replaced by perchlorate. In contrast, the CLDHs exhibited a high adsorption capacity with a nonlinear isotherm, which was mainly driven by the structural memory effect of the LDHs with perchlorate as an interlayer anion. The perchlorate uptake by the CLDHs was enhanced as the positive layer charge density decreased, which cannot be explained by anion exchange mechanism alone. According to the Cl–O and O–H stretching vibrations of the reconstructed ClO 4 - -LDHs, we proposed that perchlorate transfer a negative charge to positively hydroxide layers via electrostatic interactions, then the oxygen atoms of perchlorate are polarized by the surrounding hydroxyls and form strong hydrogen bonds with the hydroxide layers.
V Rives - One of the best experts on this subject based on the ideXlab platform.
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intercalation of drugs in Layered Double Hydroxides and their controlled release a review
Applied Clay Science, 2014Co-Authors: V Rives, Margarita Del Arco, C MartinAbstract:Abstract The intercalation of different drugs in Layered Double Hydroxides with the hydrotalcite-like structure is reviewed. The intercalation processes are carried out following different routes (direct synthesis, coprecipitation, anion exchange) and the advantages and disadvantages of these methods are described for the specific drug/LDH system studied. Characterisation of the intercalation compounds is also studied, to determine the way the guest molecules are intercalated between the layers of the Layered Double hydroxide. The controlled release (in some cases also the kinetics analysis) is also studied. We conclude that Layered Double Hydroxides are very suitable materials to host different families of drugs and in the controlled release they show benefitial properties, on comparing with the effect of the bulk drug. It should be also stressed that these are almost the unique materials (in addition to Layered hydroxy salts) able to host drugs in the anionic form, so nicely completing the studies carried out so far on the suitability of cationic clays to host cationic or neutral drugs.
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Layered Double Hydroxides as drug carriers and for controlled release of non steroidal antiinflammatory drugs nsaids a review
Journal of Controlled Release, 2013Co-Authors: V Rives, Margarita Del Arco, C MartinAbstract:Non-steroidal anti-inflammatory drugs constitute one of the groups most widely currently used, but show several problems for administration due to low solubility and delivery control. For this reason, several matrices have been tested to support them in order to overcome these drawbacks. Among them, Layered Double Hydroxides have been used in recent years. The aim of this review is to update the current knowledge and findings on this hybrid system, namely, Layered Double Hydroxides intercalated with different NSAIDs. The basic nature of the matrix introduces an additional advantage, i.e., to decrease ulceration damages. We have focused our review mostly on the preparation procedures, as these control, define and determine the performance of the systems in vitro and also in living organisms.
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chromium and yttrium doped magnesium aluminum oxides prepared from Layered Double Hydroxides
Solid State Sciences, 2007Co-Authors: J M Garciagarcia, M E Perezbernal, R J Ruanocasero, V RivesAbstract:Abstract Layered Double Hydroxides with the hydrotalcite-like structures, containing Mg2+ and Al3+, doped with Cr3+ and Y3+, have been prepared by precipitation at constant pH. The weight percentages of Cr3+ and Y3+ were 1, 2, or 3%, and 0.5 or 1%, respectively. Single phases were obtained in all cases, whose crystallinity decreased as the content in Cr and Y was increased. The solids have been characterised by element chemical analysis, powder X-ray diffraction, thermal analyses (differential, thermogravimetric and programmed reduction), FT-IR and UV–vis spectroscopies; the specific surface areas have been determined from nitrogen adsorption isotherms at −196 °C. Upon calcination at 1200 °C for 5 h in air all solids display a mixed structure (spinel and rock salt for MgO); these solids have also been characterised by these techniques and their chromatic coordinates (CIE – L∗a∗b∗) have been determined. Their pink colour makes these solids suitable for being used as ceramic pigments.
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Layered Double Hydroxides present and future
2001Co-Authors: V RivesAbstract:Layered Double Hydroxides are one of the variety of names given to a family of Layered materials first discovered in Sweden in 1842. These materials are interesting because their layer cations can be changed among a wide selection, and the interlayer anion can also be (nearly) freely chosen. Like cationic clays, they can be pillared and can exchange interlayer species -- thus increasing applications and making new routes to derivatives. The principle areas of application include catalyst support, anion scavengers, polymer stabilisers, and antacids. In the last several years, reviews and studies of LDHs have dealt with these uses. This book aims to update the current body of LDH knowledge from a wide array of views. The first section addresses the synthesis and physiochemical characterisation of these materials, and section two focuses on the applications of LDHs.
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Layered Double Hydroxides ldh intercalated with metal coordination compounds and oxometalates
Coordination Chemistry Reviews, 1999Co-Authors: V Rives, Maria Angeles UlibarriAbstract:Abstract This paper reviews the synthesis, properties and applications of Layered Double Hydroxides (LDHs), also known as anionic clays or hydrotalcite-like materials, containing intercalated anions constituted by metal complexes or oxometalates. After an introduction describing the main features of these compounds, emphasis is put on the synthesis methods, characterization and applications.
C Martin - One of the best experts on this subject based on the ideXlab platform.
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intercalation of drugs in Layered Double Hydroxides and their controlled release a review
Applied Clay Science, 2014Co-Authors: V Rives, Margarita Del Arco, C MartinAbstract:Abstract The intercalation of different drugs in Layered Double Hydroxides with the hydrotalcite-like structure is reviewed. The intercalation processes are carried out following different routes (direct synthesis, coprecipitation, anion exchange) and the advantages and disadvantages of these methods are described for the specific drug/LDH system studied. Characterisation of the intercalation compounds is also studied, to determine the way the guest molecules are intercalated between the layers of the Layered Double hydroxide. The controlled release (in some cases also the kinetics analysis) is also studied. We conclude that Layered Double Hydroxides are very suitable materials to host different families of drugs and in the controlled release they show benefitial properties, on comparing with the effect of the bulk drug. It should be also stressed that these are almost the unique materials (in addition to Layered hydroxy salts) able to host drugs in the anionic form, so nicely completing the studies carried out so far on the suitability of cationic clays to host cationic or neutral drugs.
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Layered Double Hydroxides as drug carriers and for controlled release of non steroidal antiinflammatory drugs nsaids a review
Journal of Controlled Release, 2013Co-Authors: V Rives, Margarita Del Arco, C MartinAbstract:Non-steroidal anti-inflammatory drugs constitute one of the groups most widely currently used, but show several problems for administration due to low solubility and delivery control. For this reason, several matrices have been tested to support them in order to overcome these drawbacks. Among them, Layered Double Hydroxides have been used in recent years. The aim of this review is to update the current knowledge and findings on this hybrid system, namely, Layered Double Hydroxides intercalated with different NSAIDs. The basic nature of the matrix introduces an additional advantage, i.e., to decrease ulceration damages. We have focused our review mostly on the preparation procedures, as these control, define and determine the performance of the systems in vitro and also in living organisms.
