Intercalation Of Molecules Research Articles

Graphene Bilayer as a Template for Manufacturing Novel Encapsulated 2D Materials.

Bilayer graphene (BLG) has recently been used as a tool to stabilize encapsulated single sheets of various layered materials and tune their properties. It was also discovered that the protecting action of graphene sheets makes it possible to synthesize completely new two-dimensional materials (2DMs) inside the BLG by intercalating various atoms and molecules. In comparison to the bulk graphite, BLG allows for easier intercalation and a much larger increase in the interlayer separation of the sheets. Moreover, it enables studying the atomic structure of the intercalated 2DM by using high-resolution transmission electron microscopy. In this review, we summarize the recent progress in this area, with a special focus on new materials created inside BLG. We compare the experimental findings with the theoretical predictions, pay special attention to the discrepancies, and outline the challenges in the field. Finally, we discuss unique opportunities offered by intercalation into 2DMs beyond graphene and their heterostructures.

DNA-Intercalating Supramolecular Hydrogels for Tunable Thermal and Viscoelastic Properties.

Polymeric supramolecular hydrogels (PSHs) leverage the thermodynamic and kinetic properties of non-covalent interactions between polymer chains to govern their structural characteristics. As these materials are formed via endothermic or exothermic equilibria, their thermal response is challenging to control without drastically changing the nature of the chemistry used to join them. In this study, we introduce a novel class of PSHs utilizing the intercalation of double-stranded DNA (dsDNA) as the primary dynamic non-covalent interaction. The resulting dsDNA intercalating supramolecular hydrogels (DISHs) can be tuned to exhibit both endothermically or exothermically driven binding through strategic selection of intercalators. Bifunctional polyethylene glycol (MW~2000 Da) capped with intercalators of varying hydrophobicity, charge, and size (acridine, psoralen, thiazole orange, and phenanthridine) produced DISHs with comparable moduli (500-1000 Pa), but unique thermal viscoelastic responses. Notably, acridine-based cross-linkers displayed invariant and even increasing relaxation times with temperature, suggesting an endothermic binding mechanism. This methodology expands the set of structure-properties available to biomass-derived DNA biomaterials and promises a new material system where a broad set of thermal and viscoelastic responses can be obtained due to the sheer number and variety of intercalating molecules.

DNA‐Intercalating Supramolecular Hydrogels for Tunable Thermal and Viscoelastic Properties

AbstractPolymeric supramolecular hydrogels (PSHs) leverage the thermodynamic and kinetic properties of non‐covalent interactions between polymer chains to govern their structural characteristics. As these materials are formed via endothermic or exothermic equilibria, their thermal response is challenging to control without drastically changing the nature of the chemistry used to join them. In this study, we introduce a novel class of PSHs utilizing the intercalation of double‐stranded DNA (dsDNA) as the primary dynamic non‐covalent interaction. The resulting dsDNA intercalating supramolecular hydrogels (DISHs) can be tuned to exhibit both endothermically or exothermically driven binding through strategic selection of intercalators. Bifunctional polyethylene glycol (MW~2000 Da) capped with intercalators of varying hydrophobicity, charge, and size (acridine, psoralen, thiazole orange, and phenanthridine) produced DISHs with comparable moduli (500–1000 Pa), but unique thermal viscoelastic responses. Notably, acridine‐based cross‐linkers displayed invariant and even increasing relaxation times with temperature, suggesting an endothermic binding mechanism. This methodology expands the set of structure‐properties available to biomass‐derived DNA biomaterials and promises a new material system where a broad set of thermal and viscoelastic responses can be obtained due to the sheer number and variety of intercalating molecules.

Dynamic 3D hydrogen-bond network in siloxene-water system enables efficient moisture-enabled electricity generation

Utilizing ubiquitous moisture as an energy source for moisture-enabled electric generator (MEG) has emerged as a significant technological frontier. The migration process of protons at the water/solid interface is crucial for understanding the mechanism of moisture-to-electricity conversion and efficient energy harvesting. However, the lack of clarity on this scientific question has hindered the substantive development of MEG. Here, a novel dynamic three-dimensional (3D) hydrogen-bond network between the interface of siloxene layers was designed through water molecule intercalation. The spatial bridging effect of this dynamic 3D hydrogen-bond network, formed on the siloxene layers, enhances the load transfer capability of the siloxene-water system, thereby randomizing the direction of proton hopping. Experimental and theoretical calculations demonstrate that the dynamic 3D hydrogen-bond network constructed within and between the siloxene layers facilitates rapid proton conduction. Kinetic simulations further confirm that the strength of the hydrogen-bond network accelerates proton transport rate. The current density of siloxene under high humidity increases significantly, reaching 22.37 µA cm−2, which is 122 times that under low humidity, as well as the open-circuit voltage reaches 0.73 V. This work contributes to understanding the microscopic mechanisms behind efficient moisture-enabled electricity and provides a fresh perspective for enhancing MEG performance.

Layer-Dependent Gas Sensing Mechanism of 2D Titanium Carbide (Ti3C2Tx) MXene.

Monolayers of Ti3C2Tx MXene and bilayer structures formed by partially overlapping monolayer flakes exhibit opposite sensing responses to a large scope of molecular analytes. When exposed to reducing analytes, monolayer MXene flakes show increased electrical conductivity, i.e., an n-type behavior, while bilayer structures become less conductive, exhibiting a p-type behavior. On the contrary, both monolayers and bilayers show unidirectional sensing responses with increased resistivity when exposed to oxidizing analytes. The sensing responses of Ti3C2Tx monolayers and bilayers are dominated by entirely different mechanisms. The sensing behavior of MXene monolayers is dictated by the charge transfer from adsorbed molecules and the response direction is consistent with the donor/acceptor properties of the analyte and the intrinsic n-type character of Ti3C2Tx. In contrast, the bilayer MXene structures always show the same response regardless of the donor/acceptor character of the analyte, and the resistivity always increases because of the intercalation of molecules between the Ti3C2Tx layers. This study explains the sensing behavior of bulk MXene sensors based on multiflake assemblies, in which this intercalation mechanism results in universal increase in resistance that for many analytes is seemingly inconsistent with the n-type character of the material. By scaling MXene sensors down from multiflake to single-flake level, we disentangled the charge transfer and intercalation effects and unraveled their contributions. In particular, we show that the charge transfer has a much faster kinetics than the intercalation process. Finally, we demonstrate that the layer-dependent gas sensing properties of MXenes can be employed for the design of sensor devices with enhanced molecular recognition.

Insights into molecular interactions at organic-MBene heterointerfaces for efficient Zn-ion storage

The intercalation of organic molecules is a promising approach to modulate the structure of 2D transition metal borides (MBenes), aiming to enhance charge transport and improve electrochemical performance in energy storage applications. However, key questions remain regarding how organic molecules with diverse functionalities penetrate and align between the MBene layer, as well as the mechanism of charge redistribution during intercalation. Addressing these questions is crucial for guiding the design of Organic-MBene heterostructures. To this end, a comprehensive approach combining theoretical calculations and experimental analyses was employed to explore the self-assembly mechanisms of organic molecules featuring N, O, S and tertiary amine end groups on the MoB-MBene surface. Experimental characterizations confirm that the interaction between MoB and organic compounds depends on the end groups. First principles calculations demonstrate that organic molecules tend to adopt a flat configuration on the MoB surface during molecular assembly. Calculations also reveal that the binding and charge transfer processes from organic molecules to MoB are highly dependent on the specific end groups, consistent with experimental observations. Furthermore, the effect of combining organic molecules with MoB on battery performance was further discussed, offering new insights for advancing the research and development of MBenes in aqueous battery systems.

Tunable Magnetism in 2D Organic‐Ion‐Intercalated MnPS3 via Molecule‐Dependent Vacancy Generation

AbstractThe magnetic properties of van der Waals materials are profoundly influenced by structural defects. The layered antiferromagnet MnPS3 offers a unique opportunity to explore defect‐related magnetism, as Mn2+ vacancies can be generated by the intercalation of specific guest molecules. However, the effectiveness of this process in atomically thin flakes and the extent of the magnetic tunability remain unclear. Here, it is shown that the magnetic properties of MnPS3 can be tailored through the intercalation of different guest molecules. Notably, the insertion of four alkylammonium ions introduces different populations of Mn2+ vacancies, leading to a transition from the pristine antiferromagnetic state to more complex magnetic textures, including a ferrimagnetic state displaying a magnetic saturation of 1 µB per atom. Moreover, it is shown that the intercalation of few‐nm‐thick flakes also leads to the emergence of a ferrimagnetic response. This in‐flake intercalation, which can be monitored in real time using optical microscopy, can be interrupted before completion, generating lateral heterostructures between pristine and intercalated areas. This approach opens the way to the use of partial intercalation to define regions with distinct magnetic properties within a single flake.

Ionic 2D Materials

2D materials are an exciting topic with a wide variety of applications in many research fields, from optoelectronics, photonics or qubit devices to catalysis. So far, these layered nanoscopic materials have been obtained by different procedures. In top-down approaches, from simple mechanical "Scotch tape" exfoliation to liquid exfoliation to break the weak non-covalent interactions between layers. In this project, the challenge was to obtain 2D flakes of a 3D ionic starting material with cubic rock salt structure (e.g. alkali halides NaCl, NaF, KCl, KF or CsF). They will have physical properties with substantial differences from those of known 2D materials. For example, there are few large bandgap 2D materials, almost exclusively BN layers. The BN bulk system has a band gap around 4 eV and its monolayer 6 eV, while the employed alkali halides in this project, the bulk vales are 10.0 eV (CsF), 10.9 eV (KF), 11.7 eV (NaF), KCl eV (8.5) and eV NaCl (8.6). This will open many applications that are now only restricted to BN layers. The crucial point is how it is possible to exfoliate an isotropic 3D material with ionic interactions in three spatial directions.(1,2) The intercalation of bromine molecules in CsF was corroborated, many years ago, by X-ray single-crystal diffraction.(1,3, see Figure) The intercalated structure is analogous to that of other conventional 2D materials; for example, graphene also with bromine molecules. This intercalation into the 3D structure of the alkali halide has two effects, one is to generate an anisotropic 2D structure with alternated monoatomic CsF layers and layers of Br2 molecules. The second important effect is that now for the exfoliation of the CsF-Br2 compound, only the non-ionic F···Br-Br interactions must be broken. Preliminary DFT calculations indicate that such contact energies are of the same order of magnitude as other non-covalent interactions of common 2D materials.The intercalation of such 2D materials has been performed by the intercalation of Br2 and IBr molecules combined with different exfoliation techniques (sonication-centrifugation, ball milling, microwaves..). The characterization of the 2D flakes has been performed using Atomic Force Microscopy. The final goal of this project is to make a profit from the large gap of such 2D systems for optoelectronic properties, such as single-photon emission.(1) Desmarteau, D. D.; Grelbig, T.; Hwang, S. H.; Seppelt, K., Angewandte Chemie-International Edition in English 1990, 29 (12), 1448-1449(2) Ruiz, E.; Alvarez, S., Journal of the American Chemical Society 1995, 117 (10), 2877-2883.(3) Drews, T.; Marx, R.; Seppelt, K., Chemistry-a European Journal 1996, 2 (10), 1303-1307. Figure 1

Cyclability Improvement of Recycled Graphite Materials in Lithium-Ion Batteries Via Conductive Polymer Coating

In recent years, lithium-ion batteries have been widely adopted in electric vehicles and electronics. However, the growing number of retired lithium-ion batteries poses a significant environmental challenge, generating substantial material waste and potential pollution. In most commercial batteries, graphite is the prevalent choice for anode material, owing to its high electrical conductivity and mechanical stability. Therefore, recycling graphite from spent lithium-ion batteries is a potential solution to eliminate the waste and meet the increasing demand.While considerable attention has been directed toward recovering metallic components of the spent lithium-ion batteries, limited effort has been dedicated to recycling graphite. Some previously developed methods include the pyrometallurgy process and hydrometallurgy process. However, due to high energy consumption and environmental pollutions, these methods have not been applied in large scales. Additionally, graphite particles have experienced various aging mechanisms during charge and discharge cycles, such as the formation of a solid electrolyte interface (SEI) and the intercalation of solvent molecules, potentially leading to structural alterations and degradation. Hence, it is advisable to implement surface treatment to enhance capacity stability if the recycled graphite does not perform optimally following the recovery treatment.In this study, we developed a simple process to recycle spent graphite utilizing aqueous and organic wash with N-Methylpyrrolidone (NMP) and toluene, followed by surface coating with the conductive polymer poly(9,9-dioctylfluorene-co-fluorenone-co-methylbenzoic ester) (PFM). The surface coating served as a protective layer of graphite particles and a charge transport agent to enhance conductivity. The morphologies and structures of the pristine, recycled, and PFM-coated recycled graphite samples were measured by X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis.To investigate the impact of employing PFM as a binder, electrochemical tests were done using anodes with both recycled graphite and PFM-coated recycled graphite. In recycled-graphite||NMC532 full cell testing, cells with PFM-coated recycled graphite exhibits higher coulombic efficiency (>99.90%) than cells without PFM coating at a rate of 0.33 C. A capacity retention of 77.49% was achieved for PFM-coated cells after 300 cycles, whereas the ones without coating have a capacity retention of 70.21% in average. Rate tests were also conducted on both the cells with and without PFM-coating. It shows that both types of cells support high-rate cycling. About 85% of charge capacity was delivered for cycling at 1 C for both cells with and without PFM-coating.Overall, the recycling method can be easily operated with minimal waste production, low energy consumption, and low economical costs. The PFM coating on the recycled graphite particles leads to enhancement of mechanical strength and efficiency in battery cycling.Fig. A, The process scheme of recycling graphite; B, Pictures of an electrode from spent lithium-ion batteries (left) and an electrode fabricated with recycled graphite (right); C, Capacity retention of recycled graphite without PFM coating (blue) and with PFM coating (green); D, Coulombic Efficiency of recycled graphite without PFM coating (blue) and with PFM coating (green). Figure 1

Elucidating the Interactions between Different Transition Metal Cations and Ti3C2Tx MXene through Intercalation Method for Electrochemical Applications

MXenes, are a family of two-dimensional (2D) transition metal carbides, nitrides and/ or carbonitrides.[1] The intercalation of different metal cations and organic molecules into MXene for tuning MXenes’ electronic and electrochemical properties have been widely reported.[2] [3] [4] However, transition metals (TMs) which have distinct electrochemical behaviors[5] [6] have not been explored in the literature of MXenes’ intercalation. Therefore, we herein compared the intercalation effects of different TM cations on Ti3C2Tx, for offering a general insight on the influences of multi-valent, redox-active TMs on MXenes. In particular, the changes on the physiochemical and electrochemical properties of MXenes were investigated using different in-situ and ex-situ methods, for a better understanding on the interfacial interactions of TM cations and MXenes in the confined environment of MXenes’ multilayer structures. This work serves as a foundation for the fine-tuning of MXenes’ properties by utilizing a variety of TM cations intercalation for different electrochemical systems.[1] B. Anasori, M. R. Lukatskaya, Y. Gogotsi, Nature Reviews Materials 2017, 2, 16098.[2] M. R. Lukatskaya, O. Mashtalir, E. Ren Chang, Y. Dall’Agnese, P. Rozier, L. Taberna Pierre, M. Naguib, P. Simon, M.W. Barsoum, Y. Gogotsi, Science 2013, 341, 1502-1505.[3] J. Li, H. Wang, X. Xiao, Energy & Environmental Materials 2020, 3, 306-322[4] M. Ghidiu, S. Kota, J. Halim, A. W. Sherwood, N. Nedfors, J. Rosen, V. N. Mochalin, M. W. Barsoum, Chemistry of Materials 2017, 29, 1099-1106.[5] D. Göhl, H. Rueß, M. Pander, A. R. Zeradjanin, K. J. J. Mayrhofer, J. M. Schneider, A. Erbe, M. Ledendecker, Journal of The Electrochemical Society 2020, 167, 021501.[6] M. Esmaeilirad, A. Baskin, A. Kondori, A. Sanz-Matias, J. Qian, B. Song, M. Tamadoni Saray, K. Kucuk, A. R. Belmonte, P. N. M. Delgado, J. Park, R. Azari, C. U. Segre, R. Shahbazian-Yassar, D. Prendergast, M. Asadi, Nature Communications 2021, 12, 5067.

Evolution of Oxygen Content of Graphene Oxide for Humidity Sensing.

Graphene oxide (GO) has shown significant potential in humidity sensing. It is well accepted that the oxygen-containing functional groups in GO significantly influence its humidity sensing performance. However, the relationship between the content of these groups and the humidity sensing capability of GO-based sensors remains unclear. In the present work, we investigate the role of oxygen-containing functional groups in the humidity sensing performance by oxidizing graphite with mesh numbers 80-120, 325, and 8000 using the Hummers method, resulting in GO-80, GO-325, and GO-8000. Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) were used to identify the types and quantification of oxygen-containing functional groups. Molecular dynamics simulation is used to simulate the adsorption energy, intercalation dynamics, and hydrogen bonding of water molecules. Electrochemical tests were used to compare the adsorption/desorption time and response sensitivity of graphene oxide to humidity. It is proposed that hydroxyl and carboxyl groups are the main contributing groups to humidity sensing. GO-8000 shows a relatively fast response time, but the large number of carboxyl groups will hinder intercalation of water molecules, thus exhibiting lower sensitivity. This research provides a reference for the future development of graphene-based sensors, catalysts, and environmental materials.

Enhanced Superconductivity in 2H-TaS2 Devices through in Situ Molecular Intercalation.

The intercalation of guest species into the gap of van der Waals materials often leads to the emergence of intriguing phenomena such as superconductivity. While intercalation-induced superconductivity has been reported in several bulk crystals, reaching a zero-resistance state in flakes remains challenging. Here, we show a simple method for enhancing the superconducting transition in tens-of-nanometers thick 2H-TaS2 crystals contacted by gold electrodes through in situ intercalation. Our approach enables measuring the electrical characteristics of the same flake before and after intercalation, permitting us to precisely identify the effect of the guest species on the TaS2 transport properties. We find that the intercalation of amylamine molecules into TaS2 flakes causes a suppression of the charge density wave and an increase in the superconducting transition with an onset temperature above 3 K. Additionally, we show that a fully developed zero-resistance state can be achieved in flakes by engineering the conditions of the chemical intercalation. Our findings pave the way for the integration of chemically tailored intercalation compounds in scalable quantum technologies.

Efficient removal of Eosin Yellow dye using solvothermal synthesised Ni/Al layered double hydroxide and layered double oxide: insights into adsorption kinetics and thermodynamics

ABSTRACT The accumulation of organic pollutants in the environment is swelling steadily and raising the alarm for their redressal. Layered double hydroxides (LDH) and layered double oxides (LDO) are gaining prominence for their potential to address this challenge. This work includes an eco-friendly facile solvothermal synthesis of Ni/Al LDH and their calcination to Ni/Al LDO. The prepared nanomaterials were characterised by XRD, FE-SEM, HR-TEM, FT-IR, BET and TGA techniques, which confirm the highly porous structure of synthesised nanomaterials with a high specific area of 109.94 m2g−1 and 188.94 m2g−1 for Ni/Al LDH and Ni/Al LDO, respectively. A systematic study was conducted to explore the adsorptive potential of these materials towards the removal of organic dye Eosin Yellow (EY). The adsorptive efficiency was found to be 95% and 99% for Ni/Al LDH and Ni/Al LDO, respectively, under the optimised conditions of pH, adsorbent dose, contact time, dye concentration and temperature on adsorptive removal of EY dye, which was analysed by BBD-RSM (Box-Behnken Design Response surface methodology). The adsorption data fits best with the Freundlich isotherm model and pseudo-second-order kinetics. The thermodynamic study confirms the exothermic adsorptive process. The durability and reusability of the synthesised adsorbents were ascertained by their retention of the adsorptive efficiency even after five adsorption-desorption cycles which were as high as 91% and 85% for Ni/Al LDH and Ni/Al LDO, respectively. The mechanism of adsorption involves electrostatic interaction and hydrogen bonding between the surface of adsorbent and adsorbate as well as intercalation of dye molecules.

EVALUATION OF THE GRAPHENE DISPERSIONS FOR KEVLAR FABRICS FUNCTIONALIZATION OBTAINED BY THE LIQUID-EXFOLIATION OF GRAPHITE

The process where pristine graphite is subjected to a solvent treatment seems simple and scalable and has attracted the attention of researchers over many years. However, for successful exfoliation, overcoming the van der Waals attractions between the adjacent layers of graphite is necessary. Over time, several methods have been created to overcome the attraction between layers. Graphene’s liquid phase exfoliation (LPE) occurs due to the strong interactions between the solvent molecules and the basal planes of graphite, overcoming the energetic resistance to exfoliation and subsequent dispersion. Ultra sonication used for exfoliation can produce single or few layered graphene flakes. During sonication the sound waves propagate through liquid medium in alternating high- and low-pressure cycles, strong mechanical and thermal energy released by acoustic cavitation results in splitting up large particles into fine ones and dispersing them. Simultaneous insertion of solvent and/or intercalation molecules in between the graphite layers takes place supporting graphite separation into graphene layers. ; The dispersion capacity of graphene flakes depends on how appropriate the solvent properties are to the corresponding properties of graphene, such as surface tension, Hildebrand, and Hansen solubility parameters. Only certain solvents can disperse graphene well and form a dispersion appropriate for specific future applications. In addition, after exfoliation by ultra sonication graphene flakes aggregation due to the van der Waals attractions must be overcome to prepare in long-term stable dispersions of nanometres-size graphene sheets. ; The research has focused on the preparation of stable dispersion ready for transfer without intermediate processes to the Kevlar fabrics. An experimental comparison of the potentials of the 4 solvents for the application resulted in three corresponding to the intended use, two of them examined in detail, supplementing the composition of the LPE liquid medium with triethanolamine to obtain sufficient performance graphene coverage on Kevlar textile fibres.

Room temperature synthesis of triazine covalent organic frameworks for size-selective intercalation of molecules and fast water purification

In this work, we report on a new method for the construction of triazine covalent organic frameworks on gram scale by catalyst-free cyclotrimerization of alkynes at room temperature for the size-selective intercalation of molecules and fast water purification. Reaction between sodium acetylide and cyanuric chloride resulted in 2,4,6-triethynyl-1,3,5-triazine intermediate which converted to heteroaromatic frameworks comprising triazine and benzene rings upon in situ [2 + 2+2] cyclotrimerization. Mechanistic studies revealed a crucial role for the triazine ring in susceptibility of ethynyl groups to cyclization. The permeability of these nanostructures to small molecules, exemplified by Rhodamine 6G (R6G) and HAuCl4, and their impermeability to bigger objects such gold nanoparticles (5 nm) indicated their potential to remove molecular impurities from water. Impurities including Methylene blue and Malachite green with 20 mg L−1 concentration were completely removed by 1 mg of the synthesized frameworks in 60 s. Taking advantages of the straightforward synthesis and permeability to small molecules, the synthesized triazine frameworks can be used for the fast and efficient purification of water contaminated by toxic agents.

Organoclays Based on Bentonite and Various Types of Surfactants as Heavy Metal Remediants

The rapid industrial development of civilization has led to the need for the development of new materials to clean up chemically contaminated wastewater and soils. Organoclays, based on smectite minerals and various types of surfactants, are one of the most effective sorbents for adsorbing organic and inorganic pollutants. Organoclays are clay minerals that have been modified by the intercalation or grafting of organic molecules. The main mechanism of interaction between organic substances and organoclays involves the adsorption of the substances onto the surface of the clay mineral, which has an expanded structural cell. Various types of surfactants can be used to synthesize organoclays, including cationic, anionic, and amphoteric surfactants. Each type of surfactant has different properties that affect the clay’s ability to sorb. Cationic forms of trace elements, such as heavy metals, can also be adsorbed by organoclays. Data on the adsorption of these substances by organoclays are provided, along with information on how to synthesize them using various surfactants. This review also discusses the main mechanisms of interaction between these substances and clays and the various methods used to create organoclays. It is clear that the adsorption of heavy metals by organoclays is not influenced by their structure or properties, as they belong to the category of surfactant, but rather by their overall chemical structure and characteristics. The wide variety of surfactant types leads to different effects on the adsorption properties of trace elements.

Uncalcined Zn/Al Carbonate LDH and Its Calcined Counterpart for Treating the Wastewater Containing Anionic Congo Red Dye

In this investigation, Zn/Al carbonate layered double hydroxide (ZAC-LDH) and its derived material on calcination were synthesized for removing the anionic azo dye Congo red (CR) from wastewater. Numerous factors were methodically investigated, including temperature, adsorbent dosage, pH, starting Dye Concentration (DC), and contact time. The CR elimination percentage dropped as the initial DC increased from 25 mg/L to 100 mg/L at 30 °C for uncalcined LDH, and from 97.96% to 89.25% for calcined LDH. The pH analysis indicates that the highest level of dye removal was recorded within the acidic pH range through the electrostatic attraction mechanism. The sorption kinetics analysis results demonstrated that the pseudo-second-order kinetic model exhibited a stronger fit to both uncalcined LDH and CZA-LDH, with the maximum correlation coefficient value. The Van’t Hoff plots indicate the spontaneous nature of the physisorption process with a negative ΔG° (<−20 kJ/mol), while the endothermic adsorption process exhibited a positive ΔH°. The X-ray diffraction of calcined LDH reveals a significant intercalation of CR dye molecules, both prior to and following adsorption, showcasing a distinctive memory effect. The Brunauer–Emmett–Teller (BET) gas sorption measurements were performed to support the mesoporous nature of ZAC-LDH and CZA-LDH. The FTIR spectrum confirms the interaction of dye molecules on the surface of uncalcined and calcined LDH. These findings emphasize the efficacy of both the synthesized LDHs in removing CR dye, with CZA-LDH demonstrating superior efficiency compared to uncalcined LDH in the context of CR removal from wastewater.

Intercalation in 2D materials and in situ studies.

Intercalation of atoms, ions and molecules is a powerful tool for altering or tuning the properties - interlayer interactions, in-plane bonding configurations, Fermi-level energies, electronic band structures and spin-orbit coupling - of 2D materials. Intercalation can induce property changes in materials related to photonics, electronics, optoelectronics, thermoelectricity, magnetism, catalysis and energy storage, unlocking or improving the potential of 2D materials in present and future applications. In situ imaging and spectroscopy technologies are used to visualize and trace intercalation processes. These techniques provide the opportunity for deciphering important and often elusive intercalation dynamics, chemomechanics and mechanisms, such as the intercalation pathways, reversibility, uniformity and speed. In this Review, we discuss intercalation in 2D materials, beginning with a brief introduction of the intercalation strategies, then we look into the atomic and intrinsic effects of intercalation, followed by an overview of their in situ studies, and finally provide our outlook.

Molecular Intercalation‐Induced Two‐Phase Evolution Engineering of 1T and 2H‐MS2 (M = Mo, V, W) for Interface‐Polarization‐Enhanced Electromagnetic Absorbers

AbstractPolarization at interfaces is an important loss mechanism for electromagnetic wave (EMW) attenuation, though the motion behavior of carriers in interfaces composed of different types of conductors has yet to be investigated. Tuning the phase structure of transition metal dichalcogenides (TMDs) MS2 (M = Mo, V, W) by organics small molecule intercalation to achieve the modulation of interfacial types is an effective strategy, where 1T‐MS2 exhibits metallic properties and 2H‐MS2 has semiconducting properties. To exclude the contribution of the intrinsic properties of TMDs materials, three TMDs (MoS2, VS2, and WS2), which also possess phase transitions, are investigated. Among them, the 1T‐MS2 composite exhibits excellent EMW absorption performance under the synergistic effect of interfacial polarization and conduction loss. 1T‐MoS2/MOF‐A exhibits the best EMW absorption performance with an RLmin of −61.07 dB at a thickness of 3.0 mm and an EAB of 7.2 GHz at 2.3 mm. The effectiveness of the modulation of the interfacial polarization using 1T‐phase and 2H‐phase MS2 is demonstrated, which is important for the analysis of the carrier motion behavior during the interfacial loss.

Controllable Design of Metal-Organic Framework-Derived Vanadium Oxynitride for High-Capacity and Long-Cycle Aqueous Zn-Ion Batteries.

Introducing N atoms in vanadium oxides (VOx) of aqueous Zn-ion batteries (ZIBs) can reduce their bandgap energy and enhance their electronic conductivity, thereby promoting the diffusion of Zn2+. The close-packed vanadium oxynitride (VON) generated often necessitates the intercalation of water molecules for restructuring, rendering it more conducive for zinc ion intercalation. However, its dense structure often causes structural strain and the formation of by-products during this process, resulting in decreased electrochemical performance. Herein, carbon-coated porous V2O3/VN nanosheets (p-VON@C) are constructed by annealing vanadium metal-organic framework in an ammonia-contained environment. The designed p-VON@C nanosheets are efficiently converted to low-crystalline hydrated N-doped VOx during subsequent activation while maintaining structural stability. This is because the V2O3/VN heterojunction and abundant oxygen vacancies in p-VON@C alleviate the structural strain during water molecule intercalation, and accelerate the intercalation rate. Carbon coating is beneficial to prevent p-VON@C from sliding or falling off during the activation and cycling process. Profiting from these advantages, the activated p-VON@C cathode delivers a high specific capacity of 518 mAh g-1 at 0.2 A g-1 and maintains a capacity retention rate of 80.9% after 2000 cycles at 10 A g-1. This work provides a pathway to designing high-quality aqueous ZIB cathodes.