Facile synthesis of 3D MnNi-layered double hydroxides (LDH)/graphene composites from directly graphites for pseudocapacitor and their electrochemical analysis

Lee, Ilbok,Jeong, Gyoung Hwa,An, Soyeon,Kim, Sang- Wook,Yoon, Songhun Elsevier BV * North-Holland 2018 Applied Surface Science Vol.429 No.-

<P><B>Abstract</B></P> <P>Herein, MnNi-layered double hydroxides (LDH) were imbibed within the interlayers of graphene nanosheets. The anionic surfactant, sodium dodecyl sulfate played a role of graphite exfoliator adding interaction with metal cations. Using this process, layered MnNi-LDH-graphene nanocomposite was prepared without formation of graphene oxide. When applied into pseudocapacitor electrode, LDH-graphene with optimal ratio between Mn and Ni exhibited very stable cycle with 90% at 1400 cycles and high energy 47.29Whkg<SUP>−1</SUP> at the power density of 7473Wkg<SUP>−1</SUP>, which was attributed to highly stable layered LDH structure within conductive graphene layers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3D MnNi-layered double hydroxides (LDH)/graphene were synthesized from graphite. </LI> </UL> </P> <P> <ce:list id='lis0010'> <ce:list-item id='lsti0010'> <ce:label>•</ce:label> <ce:para id='par0010' view='all'>Nanocomposite-on-graphene electrode provides fast and efficient diffusion of electrolyte ions to active material surface.</ce:para> </ce:list-item> <ce:list-item id='lsti0015'> <ce:label>•</ce:label> <ce:para id='par0015' view='all'>Mn1Ni3-LDH-G composite electrode shows optimum electrochemical performance.</ce:para> </ce:list-item> </ce:list> </P>

Pillar Host Material로써 Layered(Mg/Al) Double Hydroxide의 물리화학적 특성화

형경우,이용석 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.5

Layered double hydroxides(LDHs) [{{{{ {Mg }_{1-x } }}{{{{ {Al }_{x } }}({{{{ {OH}_{2 } }})]ζ+({{{{ {CO }`_{3 } ^{2- } ){ }_{x/2 } }}$.${{{{ { yH}_{2 }O }} wioth variation of layer charge densitywere synthesized by co-precipitation methdo since their charge densities have a very important role to be det-ermined the physicochemical properties of layered materials. The XRD IR and thermal studies of them were discussed and the kinetic study for the decarbonation reaction was also carried out. From the results of XRD analysis we found that the lattice parameter and the unit cell volume were linearly decreased with the amount of Al substituents(x) in the vicinity of x=2∼10${\times}$1/3${\times}$10-1 but they had nearly constant values when the x are far from these vicinit. The activation energies for the decarbonation reaction of x=6.8, 10${\times}$1/3${\times}${{{{ { 10}^{-1 } }} were estimated to be 47.0, 37.6, 39.3 kcal/mol The specific surface areas(90-120 m2/g) of stable hy-drotalcite-type LDHs were dractically decreased with increasing of layer charge density.

Intercalation of Europium Inclusion Complex of β-Cyclodextrin into Layered Double Hydroxides Through Layer-By-Layer Assembly and Its Luminescent Properties

Wenjun Zhang,Yi Chen,Yanlin Li,Sumin Guan,Yan Chen,Qian-Qian Yang,Lu Liu,Qing-Chen Xue,Yu-Cui Guang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.10

"In this work, organic–inorganic hybrid ultrathin transparent films (UTFs), produced by layer-by-layer (LBL) assembly of the europium inclusion complex of β-cyclodextrin ( β-CD) and Mg–Al layered double hydroxide (MgAl–NO3–LDHs) nanosheets, are reported. UV-visible (UV-Vis) absorption and fluorescence spectroscopy show orderly growth of the europium inclusion complex of β-CD/layered double hydroxide (EICC/LDH) films with an increasing number of deposition cycles. X-ray diffraction and scanning electron microscopy measurements indicate that the films feature periodic layered structures with uniform surface morphology. Moreover, when EICC is assembled with inorganic rigid LDH nanosheets, the lifetimes are prolonged due to the isolation effect, and the UTFs are transparent with high brightness, which indicate that these films could serve as new optical materials."

Intercalation of Functional Organic Molecules with Pharmaceutical, Cosmeceutical and Nutraceutical Functions into Layered Double Hydroxides and Zinc Basic Salts

황성호,한양수,최진호,Hwang, Seong Ho,Han, Yang Su,Choe, Jin Ho Korean Chemical Society 2001 Bulletin of the Korean Chemical Society Vol.22 No.9

Negatively charged functional organic molecules such as retinoic acid, ascorbic acid, indole acetic acid, citric acid, salicylic acid, acidic dye (indigo carmine, Food Blue 1) are intercalatively encapsulated by zinc basic salt (hydrozincite) and layered double hydroxide. Such functional organic-inorganic nanohybrids are realized via coprecipitation reaction involving simultaneous formation of layered inorganic lattice and intercalation of anionic species. The heterostructural nature of these nanohybrids, their particle morphology and textural characterizations are mainly discussed on the basis of Powder X-ray Diffraction and Field Emission Scanning Electron Microscopy results.

Layered Double Hydroxide를 이용한 Astaxanthin과 Cinnamic Acid의 흡착과 안정도 향상에 대한 연구

박소연(Soo-Youn Park),권영민(Young-Min Kwon),이종현(Jong-Hyeon Lee),박영아(Young-Ah Park),강유진(Yu-Jin Kang),김정동(Jeong-Dong Kim),지홍근(Hong-Geun Ji) 한국화장품미용학회 2018 한국화장품미용학회지 Vol.8 No.1

Continuous heating and solar radiation can severely reduce the chemical and biological activities of most cosmetic raw molecules. To avoid severe damages to the cosmetic molecules, it is required to develop the diverse stabilization methods such as encapsulation by liposomes, immobilization in porous solid materials. These materials also can improve thermal and photostability of active cosmetic raw molecules. The aim of this research was to synthesize hydrophobic layered double hydroxide (LDH) containing astaxanthin and cinnamic acid and to evaluate the effect of LDH for the photo and thermal stabilization of the astaxanthin and cinnamic acid. The hydrophobic LDH exhibited the improved thermal stability of astaxanthin compared to hydrophilic LDH, and Zn-LDH showed better photostability of incorporated cinnamic acid, respectively.

Hybrid Assembly of Layered Double Hydroxide Nanocrystals with Inorganic, Polymeric and Biomaterials from Micro- to Nanometer Scales

Lee, Jong Hyeon,Nam, Hye Jin,Rhee, Seog Woo,Jung, Duk-Young WILEY-VCH Verlag 2008 European journal of inorganic chemistry Vol.2008 No.36

<P>Monolayer assemblies of zeolite microcrystals, polymer nanobeads and caged proteins were successfully applied to a highly ordered MgAl-LDH monolayer by using the electrostatic attractions between the negatively charged particles and positively charged MgAl-LDH without chemical modifications. Ultrasonication leads to the monolayer assembly of ZSM-5 microcrystals with a maximum preferred contact over the MgAl-LDH monolayer, where the ZSM-5 microcrystals are oriented in the (0k0) crystallographic direction. PMMA and ferritin were also adsorbed on the monolayer LDH nanocrystal surface through self-assembly in solution. Homogeneous PMMA colloids-LDH composite layers on Si were successfully prepared, thanks to the improved interfacial compatibility between the immobilized LDH and polymer surface charges. Thermal treatment at 150 °C resulted in the formation of continuous polymer coatings over the LDH/Si monolayer. The mixing of colloidal solutions of LDH and PMMA led to the formation of bulk-type polymer-LDH composites after the melting of the polymer phase, where the polymer was homogeneously coated over the LDH crystals without the phase segregation of the LDH nanocrystals. The charged hydroxide layers of the LDH nanocrystals provided the multi-functional interface characteristics required to assemble the functional particles, resulting in the binary hybrid structures of inorganic-inorganic, polymer-inorganic or bio-inorganic composites. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)</P> <B>Graphic Abstract</B> <P>Nanosized PMMA beads were uniformly assembled on LDH nanocrystals through electrostatic interaction to form homogeneous polymer-LDH nanocomposites with conformal polymer layers. <img src='wiley_img/14341948-2008-2008-36-EJIC200800668-fig000.gif' alt='wiley_img/14341948-2008-2008-36-EJIC200800668-fig000'> </P>

Recent advances in the synthesis of layered double hydroxides nanosheets

XIE JING,KHALID ZUBAIR,오제민 대한화학회 2023 Bulletin of the Korean Chemical Society Vol.44 No.2

Layered double hydroxide (LDH) with characteristic two-dimensional structureand positive layer charge has attracted attention in a wide range of applica-tions in recent years. Although LDH with a layer-by-layer structure has highapplicability as a catalyst, adsorbent, drug reservoir, and so on, it has beensuggested that the single-layered LDH nanosheets not only enhance the per-formance but also expand the application in electrocatalyst, batteries, andsupercapacitors due to the increased active sites in nanosheets. In this review,we introduced state of the art in the synthesis of LDH nanosheets in terms ofsynthesis approaches, mechanisms, and properties of thus obtained LDHnanosheets. The synthesis approaches are primarily categorized into two parts,namely, top-down synthesis to delaminate bulk LDH and bottom-up synthesisto obtain single-layer LDH in limited space. In the first section, the exfoliationof LDH, which was realized by weakening the layer-by-layer stacking andby increasing the basal distance, was summarized mainly based on theswelling mechanism. In the second section, the bottom-up syntheses of LDHnanosheets through controlled crystal growth in confined space or restrictedsynthetic conditions are introduced.

An analytical method to characterize the crystal structure of layered double hydroxides: synthesis, characterization, and electrochemical studies of zinc-based LDH nanoplates

이재영,정지용,유태경 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Layered double hydroxide(LDH) is used in various applications due to its unique structure and relatively easy composition ratio control. However, due to the nature of the hydroxide material, it is difficult to accurately analyze the structure because it is easily oxidized at harsh condition such as high temperatures. In this study, zinc-based LDH materials were synthesized under relatively mild experimental conditions. The exact structure was analyzed using analysis techniques such as rietveld refinement, XPS, and XANES, and used as an OER anode material. Zinc-based LDH shows superior oxygen evolution reaction (OER) properties than catalysts synthesized with earth-rare metals such as Ir and Ru. This seems to be due to a unique structure in which Zn and Co exist almost in a divalent cation state, unlike previously reported LDH.

Optical Properties of Oxotitanium (Ⅳ) Meso-tetrakis(4-sulfonatophenyl)porphyrin Intercalated into the Layered Double Hydroxides (LDH) Studied by Laser Spectroscopy

Ryu, Su-Young,Yoon, Min-Joong,Choy, Jin-Ho,Hwang, Sung-Ho,Frube, Akihiro,Asahi, Tsuyoshi,Hiroshi, Masuhara Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.4

Some new nanohybrid materials have been synthesized by intercalating the oxotitanium(IV) meso-tetrakis(4- sulfonatophenyl) porphyrin$(O=Ti^{(IV)} TSPP)$ into the Zn/Al layered double hydroxides (LDHs), and their structures and photophysical properties have been investigated by various laser spectroscopic techniques. According to the XRD pattern of the synthesized nanohybrid materials, the macrocycle plane of $O=Ti^{(IV)}$ TSPP are grafted perpendicular to the LDH layers. The $O=Ti^{(IV)}$ TSPP-intercalated LDH exhibits band broadening of the absorption spectrum and a blue shift of Q-band as compared to that observed in solution. Resonance Raman spectral measurements demonstrate that the positively charged LDHs give rise to a slight decrease of the electronic density of the porphyrin ring accompanying a small change of the electronic distribution of the $O=Ti^{(IV)}$ TSPP. Consequently the LDH environment affects the energies of the two highest occupied molecular orbitals (HOMOs) of the $O=Ti^{(IV)}$) TSPP, $a_{1u}$ and $a_{2u}$, producing a mixed orbital character. Being consistent with these electronic structural changes of $O=Ti^{(IV)}$ TSPP in LDH, both the fluorescence spectral change and the fsdiffuse reflectance transient measurements imply that the photoexcitation of the $O=Ti^{(IV)}$ TSPP intercalated into LDH undergoes fast relaxation to the O=Ti(IV) $TSPP^+-LDH^- $charge transfer (CT) state within a few picoseconds, followed by a photoinduced electron transfer between the O=Ti(IV) TSPP and LDHs with a rate constant greater than %1×10^{10}S^{-1}$. No evidence is found for back electron transfer. In conclusion, the $O=Ti^{(IV)}$ TSPP intercalated LDH seems to be a possible candidate for an artificial reaction center for an efficient solar energy conversion system.

소성된 Mg-Al Layered Double Hydroxide에 의한 비소(V)의 흡착

서영진(Young-Jin Seo),강윤주(Yun-Ju Kang),최정(Jung Choi),김준형(Jun-Hyeong Kim),박만(Man Park) 한국토양비료학회 2008 한국토양비료학회지 Vol.42 No.6

Special concern has been given to the elevated arsenic content in soils because of its high mobility and toxicity. Layered double hydroxide (LDH) which has a high anionic exchange capacity is another potential anion adsorbent for toxic anions such as arsenic, chromate and selenium etc. The uptake of arsenate from aqueous solutions by the calcined Mg-Al LDH has been investigated. The sorption capacity was about 530 mmol/kg. Sorption isotherm was defined as L-type in which arsenate was removed by LDH through anion uptake reaction. Arsenate sorption by the calcined Mg-Al LDH was occurred by reconstruction of LDH"s framework. Competitive adsorption revealed that Mg-Al LDH had higher selectivity for arsenate than for sulfate. These results strongly suggest that calcined Mg-Al LDH has a promising potential for efficient removal of toxic metal oxides like arsenates from aqueous environments.