Intercalation Of Guests Research Articles

Biopolyphenol stabilized CoFe2O4-rGO/GO catalytic cleaning membrane for fast and high-efficiency contaminants removal

Utilizing membrane materials for the purification of wastewater represents an effective approach to address water scarcity. Nonetheless, the issues of membrane fouling and stability hinder their widespread application. Herein, an effective biopolyphenols (PP) modification strategy was proposed to construct strongly stable cobalt ferrite-loaded graphene oxide (CoFe2O4-rGO-PP/GO) membranes with catalytic cleaning function. Compared with the membranes without PP modification, the incorporation of polymerized tannic acid (pTA), green tea polyphenol (GTP), and black tea polyphenol (BTP) significantly improved membrane separation efficiencies of methylene blue (MB), with high removal reaching 99.11, 98.92, and 99.20 %, respectively. Notably, the CoFe2O4-rGO-pTA/GO membrane demonstrated high rejection and outstanding permeability of 167.2 L m−2 h−1 bar−1. Introducing pTA, GTP, and BTP could enhance MB degradation rate constants by 61.54, 38.46, and 19.23 % via peroxymonosulfate (PMS) activation, respectively. Remarkably, CoFe2O4-rGO-pTA/GO membrane achieved near-complete MB degradation within 12 min. Moreover, CoFe2O4-rGO-PP/GO membranes maintained high MB rejection exceeding 97 % even after ten cycles, highlighting exceptional stability and catalytic cleaning performance. The separation mechanism of these membranes was dominantly governed by the nano-confined adsorption under pressure-driven flow-through process, which was greatly distinguished from a size-sieving mechanism of densely stacked 2D lamellar membranes replying on their in-plane pores or interlayer nano/subnano-channels. This PP modification strategy can be extended to design diversified 2D lamellar membranes with guest intercalation, to achieve high stability, superior separation and multi-function.

Enhancing the kinetics of vanadium oxides via conducting polymer and metal ions co-intercalation for high-performance aqueous zinc-ions batteries

Aqueous zinc-ions batteries with low cost, reliable safety, high theoretical specific capacity and eco-friendliness have captured conspicuous attention in large-scale energy storage. However, the developed cathodes often suffer from low electrical conductivity and sluggish Zn2+ diffusion kinetics, which severely hampers the development of aqueous zinc-ions batteries. Herein, we successfully prepare Mg/PANI/V2O5•nH2O (MPVO) nanosheets through conducting polymers (polyaniline) and metal ions (Mg2+) co-intercalated strategy and systematically explore its electrochemical performance as cathode materials for aqueous zinc-ion batteries. Benefitting from the synergistic effect of polyaniline and Mg2+ co-intercalated, the MPVO exhibits larger interlayer spacing and higher electrical conductivity than the single guest intercalation, which significantly enhances the electrochemical kinetics. As a consequence, the MPVO cathodes deliver superior specific capacity, rate capability and long-term cycling performance. Moreover, multiple characterizations and theoretical calculations are executed to expound the relevant mechanism.Therefore, this work provides a novel thought for the design of high-performance cathode materials for aqueous ZIBs.

Host-Guest Intercalation Chemistry in MXenes and Its Implications for Practical Applications.

The ever-increasing demand on developing layered materials for practical applications, such as electrochemical energy storage, responsive materials, nanofluidics, and environmental remediation, requires the profound understanding and artful exploitation of interlayer engineering or intercalation chemistry. The past decade has witnessed the massive exploration of a recently discovered 2D material-transition metal carbides, carbonitrides, and nitrides (referred to as MXenes), which began to take hold of a myriad of applications owing to the abundant possibilities on their compositions and intercalation states. However, application-targeted manipulation of the material performance of MXenes is constrained by the dearth of deep comprehension on fundamental intercalation chemistry/physics. To this end, the aim of this review is to provide a holistic discussion on the intercalation chemistry in MXenes and the physical properties of MXene intercalation compounds. On the basis of this, potential solutions for the challenges confronted in the synthesis, tuning of material properties, and practical applications are proposed, which are also expected to reinvigorate the exploration of layered materials that are similar to MXenes.

A Layered Polydiacetylene Containing Hydrogen-Bonding 4,4'-Bipyridyl Guests: Reversible Color Changes with a Wide-Range Temperature Response.

Layered organic polymers have intercalation capabilities and dynamic properties. In classical intercalation chemistry, the interlayer guests are intercalated in the host layers via electrostatic interaction. The present work shows the organic layered materials with the host-guest interlayer interaction via hydrogen bond. Polydiacetylene (PDA) exhibits color changes from blue to red with the application of external stimuli, such as thermal and mechanical stresses. Here we report on a layered PDA containing 4,4'-bipyridyl in the interlayer space as a hydrogen-bonding guest. Whereas the layered PDA without interlayer guest shows the color transition at 65 °C, gradual color changes with two-stage reversibility are observed in the temperature range of -20-240 °C by the introduction of the hydrogen-bonding guest. The weaker interlayer interaction via the hydrogen bond promotes the dynamic motion directing the thermoresponsive color changes in a wide temperature range.

Cryogenic Electron Microscopy for Energy Materials.

The development of clean energy generation, transmission, and distribution technology, for example, high energy density batteries and high efficiency solar cells, is critical to the progress toward a sustainable future. Such advancement in both scientific understanding and technological innovations entail an atomic- and molecular-resolution understanding of the key materials and fundamental processes governing the operation and failure of the systems. These dynamic processes span multiple length and time scales bridging materials and interfaces involved across the entire device architecture. However, these key components are often highly sensitive to air, moisture, and electron-beam radiation and therefore remain resistant to conventional nanoscale interrogation by electron-optical methods, such as high-resolution (scanning) transmission electron microscopy and spectroscopy.Fortunately, the rapid progress in cryogenic electron microscopy (cryo-EM) for physical sciences starts to offer researchers new tools and methods to probe these otherwise inaccessible length scales of components and phenomena in energy science. Specifically, weakly bonded and reactive materials, interfaces and phases that typically degrade under high energy electron-beam irradiation and environmental exposure can potentially be protected and stabilized by cryogenic methods, bringing up thrilling opportunities to address many crucial yet unanswered questions in energy science, which can eventually lead to new scientific discoveries and technological breakthroughs.Thus, in this Account, we aim to highlight the significance of cryo-EM to energy related research and the impactful results that can be potentially spawned from there. Due to the limited space, we will mainly review representative examples of cryo-EM methodology for lithium (Li)-based batteries, hybrid perovskite solar cells, and metal-organic-frameworks, which have shown great promise in revealing atomic resolution of both structural and chemical information on the sensitive yet critical components in these systems. We will first emphasize the application of cryo-EM to resolve the nanostructure and chemistry of solid-electrolyte interphases, cathode-electrolyte interphase, and electrode materials in batteries to reflect how cryo-EM could inspire rational materials design and guide battery research toward practical applications. We then discuss how cryo-EM helped to reveal guest intercalation chemistry in weakly bonded metal-organic-frameworks to develop a complete picture of host-guest interaction. Next, we summarize efforts in hybrid perovskite materials for solar cells where cryo-EM preserved the volatile organic molecules and protected perovskites from any air or moisture contamination. Finally, we conclude with perspectives and brief discussion on future directions for cryo-EM in energy and materials science.

In Situ Formation of NiAl-Layered Double Hydroxide with a Tunable Interlayer Spacing in a Confined Impinging Jet Microreactor

This work reports for the first time an in situ synthesis of a NiAl-layered double hydroxide (NiAl-LDH) with a tunable interlayer spacing using a confined impinging jet microreactor (CIJ). It is found that CIJ allows simultaneous guest (water molecules and carbonate) intercalation and in situ growth of NiAl-LDH by imposing a proper micromixing scale in a space-confined mixing chamber. The final interlayer spacing of NiAl-LDH can be easily regulated from 0.9 to 3.6 nm by tuning the Reynolds number flow range from 4.8 × 103 to 6.7 × 102. The supercapacitor has been chosen as a model reaction to investigate the electrochemical activity of NiAl-LDHs. Results demonstrate that a higher interlayer space increases the electrochemical activity and enhances supercapacitor performances due to improvement in space accessibility of NiAl-LDHs during the faradaic redox reaction. NiAl-LDH with an interlayer space up to 3.6 nm presents fairly good performance as a supercapacitor electrode material in terms of specific capacitance (1285.2 F·g–1 at 1 A·g–1) and stability (capacitance retention rates over 80% after 5000 cycles). This work develops a rapid and continuous flow methodology for a one-pot, in situ formation of NiAl-LDH with the controlled interlayer spacing via microreactor technology.

Molecular Dynamics Simulation of Cellulose I-Ethylenediamine Complex Crystal Models.

Cellulose I fibrils swell on exposure to ethylenediamine (EDA), which forms the cellulose I-EDA complex. These are regarded as host materials with guest intercalation. The present study reports molecular dynamics (MD) simulations of cellulose I-EDA crystal models with finite fiber to reproduce desorption of EDA molecules. The force field parameters for EDA were improved. Part of the EDA molecules was desorbed only from the surfaces of the crystal models, not from their interiors. The EDA molecules diffused through a hydrophilic channel composed of the hydrophilic edges of the cellulose chains, and their conformations and orientations changed. With the configuration of the cellulose chains being held, the vacant hydrophilic channel was immediately filled with water molecules. The innermost part of the crystal models, defined as a core unit, was partly deformed from the initial crystal structure, including the changes in the exocyclic group conformations of the cellulose chains and the orientations of the EDA molecules, coupled with partial reconfiguration of the intermolecular hydrogen bonding scheme. A possible crystalline conversion scheme after complete desorption of EDA has been discussed based on the present findings.

A highly stable, luminescent and layered zinc(II)-MOF: Iron(III)/copper(II) dual sensing and guest-assisted exfoliation

A highly stable and luminescent metal-organic framework (LMOF) with layered structure, namely, C6H4N5OZn (1) has been successfully achieved and fully characterized by single crystal X-ray diffraction, powder X-ray diffractions, fluorescence titration and thermogravimetry. This blue-light emitting compound 1 exhibit outstanding stability and can detect Fe3+ and Cu2+ in water specifically, presenting potential application in the field of fluorescent probe technology. Fluorescence titration experiments indicate that the detection of Fe3+ ions by 1 is more significant than that of Cu2+ ions in terms of Ksv value. Furthermore, guest-assisted exfoliation of layered MOF 1 is efficiently carried out through ether OH hydrogen bond or π···π interactions between the layered host structure and intercalated guest molecules (4,4′-oxybisbenzoic acid and triphenylamine). Tyndal scattering was observed in the suspensions of obtained MOF nanosheets. This study shows that the compound 1 with unique metal ion sensing properties can be applied as a probe material in water pollution treatment field, but also opens up the opportunity for synthesizing luminescent MONs through the “bottom-up” guest intercalation methodology.

A general synthesis strategy for the multifunctional 3D polypyrrole foam of thin 2D nanosheets

A 3D macroporous conductive polymer foam of thin 2D polypyrrole (PPy) nanosheets is developed by adopting a novel intercalation of guest (monomer Py) between the layers of the lamellar host (3D vanadium oxide foam) template-replication strategy. The 3D PPy foam of thin 2D nanosheets exhibits diverse functions including reversible compressibility, shape memory, absorption/adsorption and mechanically deformable supercapacitor characteristics. The as-prepared 3D PPy foam of thin nanosheets is highly light weight with a density of 12 mg·cm-3 which can bear the large compressive strain up to 80% whether in wet or dry states; and can absorb organic solutions or extract dye molecules fast and efficiently. In particular, the PPy nanosheet-based foam as a mechanically deformable electrode material for supercapacitors exhibits high specific capacitance of 70 F·g-1 at a fast charge-discharge rate of 50 mA·g-1, superior to that of any other typical pure PPy-based capacitor. We envision that the strategy presented here should be applicable to fabrication of a wide variety of organic polymer foams and hydrogels of low-dimensional nanostructures and even inorganic foams and hydrogels of low-dimensional nanostructures, and thus allow for exploration of their advanced physical and chemical properties.

Emergence of temperature-dependent and reversible color-changing properties by the stabilization of layered polydiacetylene through intercalation

The stimuli-responsive color-changing properties of functional polymers are applied to the development of sensing and imaging devices. Tuning the stimuli responsivity is required for a wide range of applications. Polydiacetylene (PDA) derivatives show color changes with the application of external stimuli, such as heat and mechanical stress. Our group has focused on the layered crystal structure of PDA and its intercalation chemistry. The original layered PDA shows an irreversible color transition from blue to red upon heating to the threshold temperature. Here, we found that alkyldiamine-intercalated PDA possessed different color-changing properties, such as a higher color transition temperature and a temperature-dependent and reversible color change, than the original PDA. As the alkyl-chain length increased, the color-changing behavior gradually converted from the irreversible color transition type to the reversible temperature-dependent one. Since the intercalated diamine had a stabilizing effect on the layered structure, the stimuli responsivity varied according to the type of diamine. The results suggest that the stimuli-responsive color-changing properties of layered PDA can be finely and systematically tuned by the intercalation of organic guests. Polydiacetylene (PDA) derivatives exhibit color change with application of external stimuli, such as heating and mechanical stress. The original layered PDA shows the irreversible color transition from blue to red with heating at the threshold temperature. Here we found that the alkyldiamine-intercalated PDA induced the different color-change properties, such as the raise of the color-transition temperature, the temperature-dependent color-change, and the reversible color change. The intercalated diamines have the stabilization effect of the layered polymer. The stimuli-responsive color-change properties can be tuned by the intercalated organic guests.

Lowering Band Gap of an Electroactive Metal-Organic Framework via Complementary Guest Intercalation.

A new honeycomb-shaped electroactive metal-organic framework (MOF) has been constructed from an electron deficient naphthalenediimide (NDI) ligand equipped with two terminal salicylic acid groups. π-Intercalation of electron-rich planar tetrathiafulvalene (TTF) guests between the NDI ligands stacked along the walls lowers the electronic band gap of the material by ca. 1 eV. An improved electron delocalization through the guest-mediated π-donor/acceptor stacks is attributed to the diminished band gap of the doped material, which forecasts an improved electrical conductivity.

Successive stepwise evolution of host layer-stacking framework upon the intercalation of mobile vapor guests within side-chain layers

For the ordered phases of hairy-rod semiconductive poly(2,5-bis(3-tetradecylthiophene-2-yl)thieno[3,2-b]thiophene) (PBTTT) sandwiched in between crystalline platelets of hexamethylbenzene, the successive stepwise evolution of layer-stacking framework upon guest intercalation has been studied in this research. The direct consequence of the guest intercalation into side-chain layers is evaluated to cause the lateral shift of thiophene backbones along π–π stacking, resulting in stepwise shift of ultraviolet absorption wavelength. The thermal motions of vapor guests within disordering side-chain layers subsequently cause progressive expansion of host stacking framework. With the increase in side-chain length, thicker layers of disordering side chains in liquid crystals (LCs) accommodate additional vapor guests and larger amplitudes of thermal motions of guests, hence promoting the level of reversible d-spacing change. The mixing between mobile vapor guests and aliphatic side chains is clarified as the mechanism of guest intercalation, which rationalizes successive guest intercalation during heating and the contribution of disordering side-chain layers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017

Hydrogen-bonding networks of purine derivatives and their bilayers for guest intercalation

6-Chloro-9-propyl-purin-2-amine (pr-GCl) forms two-dimensional hydrogen-bonded networks which in turn stack via π–π interactions, leading to the formation of bilayers that can accommodate organic guest molecules.

Theoretical investigation of Chevrel phase materials for cathodes accommodating Ca2+ ions

The Chevrel phase compounds Mo6X8 (X = S, Se, Te) are theoretically studied by ab initio methods as potential candidates for battery cathode materials. The voltage profiles are calculated for the cases of various alkaline earth metals (Mg, Ca, Sr, Ba) serving as guest intercalation ions. The Ca ions are shown to offer the practically significant voltage of ∼1.0–1.25 V, with S substitution giving the highest voltage over Se and Te. We further demonstrate that doubling the capacity of such a battery would also be possible by incorporating a second Ca ion near the Mo6X8 cluster. The electronic properties of this material are investigated, revealing that the entire Mo6 cluster behaves as a redox center. Finally, the ion diffusion barriers are calculated, showing comparable values to existing battery materials. This work demonstrates that the Chevrel phase may be useful as a cathode material for intercalating divalent ions, and also offers insights into possible tuning of cathode properties by judicious selection of the constituents.

Hierarchical Architecturing for Layered Thermoelectric Sulfides and Chalcogenides.

Sulfides are promising candidates for environment-friendly and cost-effective thermoelectric materials. In this article, we review the recent progress in all-length-scale hierarchical architecturing for sulfides and chalcogenides, highlighting the key strategies used to enhance their thermoelectric performance. We primarily focus on TiS2-based layered sulfides, misfit layered sulfides, homologous chalcogenides, accordion-like layered Sn chalcogenides, and thermoelectric minerals. CS2 sulfurization is an appropriate method for preparing sulfide thermoelectric materials. At the atomic scale, the intercalation of guest atoms/layers into host crystal layers, crystal-structural evolution enabled by the homologous series, and low-energy atomic vibration effectively scatter phonons, resulting in a reduced lattice thermal conductivity. At the nanoscale, stacking faults further reduce the lattice thermal conductivity. At the microscale, the highly oriented microtexture allows high carrier mobility in the in-plane direction, leading to a high thermoelectric power factor.

ChemInform Abstract: On Some Problems of Inorganic Supramolecular Chemistry

AbstractReview: 15 refs.

Eu3+ luminescence enhancement by intercalation of benzenepolycarboxylic guests into Eu3+-doped layered gadolinium hydroxide

Two benzenepolycarboxylic organic sensitizers, 1,3,5-benzenetricarboxylic acid (BTA) and 1,2,4,5-benzenetetracarboxylic acid (BA), were intercalated into the gallery of NO3− type Eu3+-doped layered gadolinium hydroxide (NO3–LGdH:Eu). CHN analysis, FTIR, and SEM were employed to characterize the intercalation structures of the as-prepared organic/inorganic hybrids. The area per unit charge (Scharge) was used to explain the intercalation structure and the arrangement of the interlayer guests. Different structures of the two organic compounds resulted in varied arrangement of guests. Photoluminescence studies indicated that both of the two organic compounds especially BA markedly enhanced the red luminescence of Eu3+ due to efficient energy transfer between the organic guests and Eu3+ centers.

On Some Problems of Inorganic Supramolecular Chemistry

In this study, some features that distinguish inorganic supramolecular host-guest objects from traditional architectures are considered. Crystalline inorganic supramolecular structures are the basis for the development of new functional materials. Here, the possible changes in the mechanism of crystalline inorganic supramolecular structure self-organization at high interaction potentials are discussed. The cases of changes in the host structures and corresponding changes in the charge states under guest intercalation, as well as their impact on phase stability and stoichiometry are considered. It was demonstrated that the deviation from the geometrical and topological complementarity conditions may be due to the additional energy gain from forming inorganic supramolecular structures. It has been assumed that molecular recognition principles can be employed for the development of physicochemical analysis and interpretation of metastable states in inorganic crystalline alloys.

Unveiling Chemical Reactivity and Structural Transformation of Two-Dimensional Layered Nanocrystals

Two-dimensional (2D) layered nanostructures are emerging fast due to their exceptional materials properties. While the importance of physical approaches (e.g., guest intercalation and exfoliation) of 2D layered nanomaterials has been recognized, an understanding of basic chemical reactions of these materials, especially in nanoscale regime, is obscure. Here, we show how chemical stimuli can influence the fate of reaction pathways of 2D layered nanocrystals. Depending on the chemical characteristics (Lewis acid ((1)O2) or base (H2O)) of external stimuli, TiS2 nanocrystal is respectively transformed to either a TiO2 nanodisc through a "compositional metathesis" or a TiO2 toroid through multistage "edge-selective structural transformation" processes. These chemical reactions can serve as the new design concept for functional 2D layered nanostructures. For example, TiS2(disc)-TiO2(shell) nanocrystal constitutes a high performance type II heterojunction which not only a wide range solar energy coverage (~80%) with near-infrared absorption edge, but also possesses enhanced electron transfer property.

The selective intercalation of organic carboxylates and sulfonates into hydroxy double salts

This paper reports the first systematic investigation of the selectivity of organic guest intercalation into hydroxy double salts. The organic guests 1,2- and 1,4-benzenedicarboxylate (1,2- and 1,4-BDC) have been incorporated into a range of hydroxy double salts by anion exchange. Intercalates of [Zn5(OH)8](NO3)2·yH2O, [Zn5(OH)8]Cl2·yH2O, [Zn5(OH)8](CH3COO)2·yH2O, [Zn3Ni2(OH)8](NO3)2·yH2O, and [Zn3.8Co1.2(OH)8](NO3)2·yH2O were prepared, and the resultant materials fully characterized. 1,5- and 2,6-Napthalanedisulfonate (1,5- and 2,6-NDS) were also successfully intercalated into the [Zn5(OH)8](NO3)2·yH2O material. It was found that the initial anions are almost completely replaced by the new organic guests in the majority of cases. Selected reactions were investigated by in situ X-ray diffraction, and the reactions observed to proceed directly from the host to the product largely under nucleation control. No intermediate phases were detected. The competitive intercalation of isomeric pairs of guest anions was explored, and very high degrees of preferential intercalation found for 1,4- over 1,2-BDC into all hydroxy double salts (HDSs) studied, and for 2,6- over 1,5-NDS into [Zn5(OH)8](NO3)2·yH2O. The selectivity was found to be largely invariant with reaction time, reaction temperature, solvent system, and guest concentration. It was also observed to be very similar across all the HDSs explored. In situ diffraction and NMR demonstrate that the selective intercalation is a thermodynamically controlled phenomenon. It is therefore suggested that preferential intercalation is governed in the main by the strength of the interactions between the HDS layers and the guest ions.