Interlayer Expansion Research Articles

Constructing SDBS-intercalated MoS2 nanosheets confined and near-vertically grown on network biochar adsorbent: Insights into highly efficient co-adsorption of ciprofloxacin and lead ions

To overcome the problems of the weak adsorption ability of biochar to heavy metal ions (HMIs) and competitive adsorption between HMIs and antibiotics during co-adsorption, the adsorbent material in which 2D sodium dodecylbenzenesulfonate-intercalated molybdenum disulfide nanosheets confined and growing near-vertically on 3D network biochar (SDBS-MoS2/BC) was synthesized. The SDBS-MoS2/BC demonstrated good adsorption ability for ciprofloxacin (CIP) and lead ions (Pb2+). Notably, the adsorption capacity of SDBS-MoS2/BC for the target in the binary system remains higher than in the single system, even at elevated concentrations of the competing target (Qmax,CIP = 393.701 mg g−1, Pb2+: 100 mg/L; Qmax,Pb = 264.550 mg g−1, CIP: 100 mg/L). This may be due to the improvement in the utilization of edge/interlayer adsorption sites by the near-vertical SDBS interlayer expansion of MoS2 as a heavy metal ion anchor. Furthermore, the spatial difference between the upper edge site of near-vertical SDBS-MoS2 and the BC plane, that is, the “longitudinal steric effect”, can separate the CIP and Pb2+ adsorptions in a different horizontal plane to avoid competitive adsorption. The underlying adsorption mechanism was elucidated through a series of experiments and the analysis of characterization results. Furthermore, the load of the SDBS-MoS2/BC sponge-packed column can continuously remove contaminants from water. The rapid, anti-interference, multifunctional and reusable properties make SDBS-MoS2/BC promising for excellent environmental treatment.

Cold-sintered self-assembly of layer-ordered hydroxyapatite nanowire arrays for efficient oil/water separation

Modified membranes and block materials with abundant porous structures have been extensively studied for oil/water separation due to their unique wettability and high specific surface area, crucial factors for high separation efficiency. This study used oleic acid to induce the hierarchical self-assembly of hydrophobic hydroxyapatite nanowires during the cold sintering process, producing a dense, layer-wise stretchable block structure. This cold sintering process sample exhibits interlayer expansion when immersed in water, spatially transitioning from a dense block to a loose, two-dimensional hydrophobic film. The small-volume, dense block contains a hydrophobic layer structure, enriching the specific surface area and integrating the advantages of hydrophobic membranes and block materials with a high specific surface area, offering a novel approach to creating dense and efficient oil/water separation materials. It grants an economical and environmentally friendly solution for large-scale oil/water separation in practical applications.

An insight into annealing mechanism of graphitized structures after irradiation

Graphite components are constantly subjected to a combined actions of annealing and irradiation due to high temperatures and thermal spike caused by irradiation when reactors are operating, resulting in complex microstructures along with matching changes in the material properties and dimensions. This study investigates the evolution process of initial irradiation defects at different annealing temperatures, which is difficult to captured by experiment. The findings indicate that 923K reactor-temperature annealing can also quickly restore isolated self-interstitial atoms and small-sized point defect clusters to intralayer locations on the nanosecond scale. However, multi-interlayer penetration damages and localized point defect aggregation from high-energy irradiation can lead to the disappearance of layered structural information, which allows these damage structures to develop into interlayer dislocations during annealing process. These interlayer dislocations further exacerbate the interlayer expansion of graphite crystal and may elucidate the mechanism behind volume expansion in nuclear graphite within reactors. Fully amorphized regions can also regain a layered structure approximately when guided by residual layered structures at 2000K, while chaotic regions or disordered layered structures form in the absence of guidance. These chaotic regions significantly exacerbate the volume expansion of graphite model, which may be related to the rapid volume increase observed in nuclear graphite components at the end of reactor life. The study provides insights into the transformation of initial irradiation defects into different types of defects under different temperatures and damage states, which serve as a critical foundation for assessing the evolution of irradiation defects in nuclear graphite for reactor applications and annealing studies.

Phase Engineering of Two-Dimensional WS2 Nanostructures for Superior Hybrid Supercapacitors

Two-dimensional (2D) tungsten sulfide (WS2) has recently emerged as a nontrivial material for electrochemical applications; however, the boundaries associated with its 1T (instability) and 2H (low electrical conductivity) phases limit its electrochemical parameters. In this work, this issue is addressed using an exclusive chemical approach to evolve a dual-phase 1T-2H WS2 heterostructure that combines two different 1T (trigonal) and 2H (hexagonal) phases directly on the current collector which demonstrated 2D transformable phase structure, large interlayer distance, and highly exposed edge active sites. A simple inert-atmosphere annealing approach under phosphorus vapors is designed to elicit a fractional phase conversion of WS2 from conventional 2H to the 1T phase, where phosphorus is accommodated in the WS2 interspace and lattice, resulting in interlayer expansion. Theoretical calculations confirmed that the 1T WS2 structure formed after phosphorus doping exhibits semimetallic feature with no band gap, thereby elucidating the high electrical conductivity. The presence of edge-enriched metallic phase and interlayer engineering of 1T-2H WS2 heterostructure validates the exceptional sodium (Na+) ion intercalation when tested in hybrid supercapacitor (HSCs) against Prussian blue analog (PBA) cathodes. As a result, the assembled HSC cell with a 1T-2H WS2 heterostructured anode and a CuFe-PBA cathode shows superior specific energy of 65.5 Wh kg-1 at a specific power of 784 W kg-1, and maintains 75% rate capability and 95.7%cycling stability over 10,000 cycles. This work paves a technique for engineering a simple phase transition of 2D materials and sheds light on the expansion of high-performance next-generation energy storage systems.

Ultra-Wide Interlayered WxMo2xSy Alloy Electrode Patterning through High-Precision Controllable Photonic-Synthesis.

Ultra-thin 2D materials have great potential as electrodes for micro-supercapacitors (MSCs) because of their facile ion transport channels. Here, a high-precision controllable photonic-synthesis strategy that provided 1inch wafer-scale ultra-thin film arrays of alloyed WxMo2xSy with sulfur vacancies and expanded interlayer (13.2Å, twice of 2H MoS2) is reported. This strategy regulates the nucleation and growth of transition metal dichalcogenides (TMDs) on the picosecond or even femtosecond scale, which induces Mo-W alloying, interlayer expansion, and sulfur loss. Therefore, the diffusion barrier of WxMo2xSy is reduced, with charge transfer and ion diffusion enhancing. The as-prepared symmetric MSCs with the size of 100×100µm2 achieve ultrahigh specific capacitance (242.57mFcm-2 and 242567.83Fcm-3), and energy density (21.56Whcm-3 with power density of 485.13Wcm3). The established synthesis strategy fits numerous materials, which provides a universal method for the flexible synthesis of electrodes in microenergy devices.

Significant role of interlayer in strontium adsorption on weathered biotite

Weathering of micaceous minerals play a significant role in the adsorption and migration of radioactive strontium. Weathering changes the structure of minerals and the capacity of adsorption sites on their surfaces. The regulatory mechanism of environmental factors on radioactive strontium on weathered micaceous minerals remains to be sorted out and clarified. In this work, we studied the adsorption behavior of Sr2+ on weathered micaceous minerals with different weathering degrees via batch experiments and spectroscopic approaches. The batch experiment results indicated that the adsorption capacity of Sr2+ increased from 5.36 mg/g (Na-Bio) to 19.89 mg/g (SCa-Bio) as the weathering degree of biotite increased. The outer-sphere complexation and electrostatic attraction/ion exchange mainly governed the adsorption of Sr2+ on weathered biotite. The type of cation co-existing in solution and the weathering degree of biotite regulate Sr2+ adsorption into the interlayers. Owing to their similar ionic properties (e.g., hydration energy and hydrated radius), Sr2+ competed more fiercely with Ca2+ for adsorption sites. Hydrated Na+ and Sr2+ could enter and adsorb on the interlayer, but the difference is that the hydrated Na+ collapsed the interlayer of weathered biotite (from 15.0 Å to 11.8 Å), while the hydrated Sr2+ expanded the interlayers (from 12.0 Å to 14.8 Å). Nevertheless, the hydrated Sr2+ could occupy most interlayers when Na+ and Sr2+ co-existed in the solution. It was noted that dehydrated K+ present in the interlayer of weathered biotite could collapse the expanded interlayer of biotite. The d-spacing of weathered biotite (e.g., SCa-Bio) would decrease from 15.0 Å to 10.4 Å, significantly limiting the interlaminar adsorption of Sr2+. Furthermore, this inhibitory effect was based on the high weathering degree of micaceous minerals and the noticeable interlayer expansion. XPS results demonstrated that the co-existing cations hardly influence the adsorption form of Sr2+ on weathered micaceous minerals. The above findings provide intrinsic insights into the understanding of radioactive strontium transport and fate in the environment.

Dual Strategy of Morphology Optimization and Interlayer Expansion in VS2 Cathode Toward High-Performance Mg-Li Hybrid Ion Batteries.

Combining the merits of the dendrite-free formation of a Mg anode and the fast kinetics of Li ions, the Mg-Li hybrid ion batteries (MLIBs) are considered an ideal energy storage system. However, the lack of advanced cathode materials limits their further practical application. Herein, we report a dual strategy of morphology optimization and interlayer expansion for the construction of hierarchical flower-like VS2 architecture coated by N-doped amorphous carbon layers. This tailored hierarchical flower-like structure coupled with homogeneous N-doped amorphous carbon layers cooperatively provide more active sites and buffer volume changes, thus realizing the enhancement of capacity and structural stability. Moreover, the enlarged interlayer spacing caused by the cointercalation of polyvinylpyrrolidone and ammonium ions can effectively promote the charge transfer rate and facilitate the rapid ion diffusion, as further demonstrated by electrochemical results and theoretical calculations. These features endow the hierarchical flower-like VS2 cathode with superior specific energy density (644.4 Wh kg-1, average voltage of 1.2 V vs Mg2+/Mg) and excellent rate capability (181.1 mAh g-1 at 2000 mA g-1). Systematic ex situ characterization measurements are employed to reveal the ion storage mechanism, which confirms that Li+ storage plays a leading role in the capacity contribution of MLIBs. Our strategy is in favor of providing useful insights to design and construct MLIBs with high energy density and excellent rate performance.

Interlayer expansion and conductive networking of MoS2 nanoroses mediated by bio-derived carbon for enhanced potassium-ion storage

Potassium-ion batteries (PIBs) represent a promising battery technology for energy storage applications. Nevertheless, the progress of PIBs is still hindered by the lack of electrode materials that allow rapid and repeatable accommodation of the large K+ ions. Herein, a composite anode material containing interlayered-expanded MoS2 (55.6% larger) nanoroses in carbon nanonets (MoS2/C@CNs) is designed with the assistance of biomass bagasse, of which the dual carbon sources convert into interlayer and skeleton carbon, respectively. The unique structure facilitates electron/ion transport in the entire electrode and offers excellent structural stability, leading to much improved electrochemical performance compared to simple MoS2/C composite and pure MoS2. Furthermore, the role of electrolyte salts (potassium hexafluorophosphate and potassium bis(fluorosulfonyl)imide) and the electrolyte concentration on the interfacial properties in PIBs have been explored. The results indicate that the low-concentration potassium bis(fluorosulfonyl)imide electrolyte helps to produce optimized organic-inorganic solid electrolyte interface films, contributing to a capacity retention of 90% after 1,000 cycles at 2 A g-1.

Multifunctional Applications Enabled by Fluorination of Hexagonal Boron Nitride.

2D materials exhibit exceptional properties as compared to their macroscopic counterparts, with promising applications in nearly every area of science and technology. To unlock further functionality, the chemical functionalization of 2D structures is a powerful technique that enables tunability and new properties within these materials. Here, the successful effort to chemically functionalize hexagonal boron nitride (hBN), a chemically inert 2D ceramic with weak interlayer forces, using a gas-phase fluorination process is exploited. The fluorine functionalization guides interlayer expansion and increased polar surface charges on the hBN sheets resulting in a number of vastly improved applications. Specifically, the F-hBN exhibits enhanced dispersibility and thermal conductivity at higher temperatures by more than 75% offering exceptional performance as a thermofluid additive. Dispersion of low volumes of F-hBN in lubricating oils also offers marked improvements in lubrication and wear resistance for steel tribological contacts decreasing friction by 31% and wear by 71%. Additionally, incorporating numerous negatively charged fluorine atoms on hBN induces a permanent dipole moment, demonstrating its applicability in microelectronic device applications. The findings suggest that anchoring chemical functionalities to hBN moieties improves a variety of properties for h-BN, making it suitable for numerous other applications such as fillers or reinforcement agents and developing high-performance composite structures.

Strain Engineering of Ion-Coordinated Nanochannels in Nanocellulose.

Expanding the interlayer spacing plays a significant role in improving the conductivity of a cellulose-based conductor. However, it remains a challenge to regulate the cellulose nanochannel expanded by ion coordination. Herein, starting from multiscale mechanics, we proposed a strain engineering method to regulate the interlayer spacing of the cellulose nanochannels. First-principles calculations were conducted to select the most suitable ions for coordination. Large-scale molecular dynamics simulations were performed to reveal the mechanism of interlayer spacing expansion by the ion cross-linking. Combining the shear-lag model, we established the relationship between interfacial cross-link density and interlayer spacing of an ion-coordinated cellulose nanochannel. Consequently, fast ion transport and current regulation were realized via the strain engineering of nanochannels, which provides a promising strategy for the current regulation of a cellulose-based conductor.

Pyrolysis fuel oil-derived hollow carbon nanocages as high-stability anode materials for potassium ion storage

The use of graphite to make anode materials for potassium-ion batteries (KIBs) results in diminished electrochemical performance, largely due to significant interlayer expansion caused by potassation/depotassiation. To address this limitation, novel hollow carbon nanocages (HCNCs) are prepared from pyrolysis fuel oil (PFO), a cost-effective byproduct. The HCNCs heat-treated at 1500 °C has a graphitic structure with high porosities and numerous closed pores and exhibits a notable potassium-ion storage capacity of 307.2 mAh/g at a current density of 50 mA g−1. Moreover, structurally stable HCNCs withstand the substantial volume expansion associated with potassium-ion intercalation. The stability of the material is attributed to a hybrid adsorption/insertion mechanism, which results from synergistic interplay between the unique morphologies of the HCNCs and the developed carbon layers. This configuration delivers a specific capacity of 131.6 mAh/g and 98.9 % capacity retention over 1000 cycles at a high current density of 2000 mA g−1. Consequently, these proposed HCNCs present a significant advance in developing efficient carbon materials for KIBs, and addressing the critical challenges of graphite such as unstable cycling stability.

Experimental investigation on nonlinear flow and solute transport behavior in interlayer expansion fractures

Experimental investigation on nonlinear flow and solute transport behavior in interlayer expansion fractures

Interchain-expanded extra-large-pore zeolites.

Stable aluminosilicate zeolites with extra-large pores that areopen through rings of more than 12 tetrahedra could be used to process molecules larger than those currently manageable in zeolite materials. However, until very recently1-3, they proved elusive. In analogy to the interlayer expansion of layered zeolite precursors4,5, we report a strategy that yields thermally and hydrothermally stable silicates by expansion of a one-dimensional silicate chain with an intercalated silylating agent that separates and connects the chains. As a result, zeolites with extra-large pores delimited by 20, 16 and 16 Si tetrahedra along the three crystallographic directions are obtained. The as-made interchain-expanded zeolite contains dangling Si-CH3 groups that, by calcination, connect to each other, resulting in a true, fully connected (except possible defects) three-dimensional zeolite framework with a very low density. Additionally, it features triple four-ring units not seen before in any type of zeolite. The silicate expansion-condensation approach we report may be amenable to further extra-large-pore zeolite formation. Ti can be introduced in this zeolite, leading to a catalyst that isactive in liquid-phase alkene oxidations involving bulky molecules, which shows promise in the industrially relevant clean production of propylene oxide using cumene hydroperoxide as an oxidant.

Hydrophilized MoS2 as Lubricant Additive

Molybdenum disulfide (MoS2) has been used in a variety of lubrication products due to its highly tunable surface chemistry. However, the performance of MoS2-derived tribofilms falls short when compared to other commercially available antiwear additives. The primary objective of this study is to improve the tribological performance of MoS2 as an additive for lithium-based greases. This was achieved by functionalizing the particle with hydrophilic molecules, such as urea. Experimental results indicate that the urea-functionalized MoS2 (U-MoS2) leads to a notable decrease in the coefficient of friction of 22% and a substantial reduction in the wear rate of 85% compared to its unmodified state. These results are correlated with the density functional theory (DFT) calculation of U-MoS2 to theorize two mechanisms that explain the improved performance. Urea has the capability to reside both on the surface of MoS2 and within its interlayer spacing. Weakened van der Waals forces due to interlayer expansion and the hydrophilicity of the functionalized U-MoS2 surface are catalysts for both friction reduction and the longevity of tribofilms on hydrophilic steel surfaces. These findings offer valuable insights into the development of a novel class of lubricant additives using functionalized hydrophilic molecules.

Pomegranate-like α-MoO3-x/C nanospheres as a stable and high-performance Li-ion intercalation host

Orthorhombic MoO3 (α-MoO3) is extensively investigated as a cathode material in Li-ion batteries with high capacity. However, suffering from the irreversible structural transformation and rapid capacity decline during discharge-charge process are still annoyed issues for α-MoO3 based electrodes. Herein, novel pomegranate-like oxygen-deficient α-MoO3/C (α-MoO3-x/C) nanospheres are prepared. The α-MoO3-x/C nanosphere is comprised of ultrafine α-MoO3-x subunits and porous graphitic carbon framework. Interlayer expansions caused by different contents of oxygen vacancies are realized in α-MoO3-x via a controllable oxidation process. When evaluated as the Li-ion intercalation host, the α-MoO3-x/C containing appropriate oxygen vacancies is found to be optimal with remarkable rate capability (230.0 mAh g−1 at 1 C, 54.5 mAh g−1 at 50 C) and long lifetime (69.6% retention after 3000 cycles at 10 C). Electrochemical test shows that the behavior of Li-ion intercalation in the intralayers of α-MoO3-x/C is suppressed effectively and becomes reversible. The structure evolutions during Li-ion intercalation/deintercalation process are investigated by ex situ X-ray diffraction, which reveals that α-MoO3-x/C undergoes lattice breathing rather than structural collapse compared with pure α-MoO3. Moreover, α-MoO3-x/C exhibits enhanced pseudocapacitance and improved Li-ion transport kinetics than pure α-MoO3. These unique features render α-MoO3-x/C an advanced intercalation host for Li-ions.

Low pressure reversibly driving colossal barocaloric effect in two-dimensional vdW alkylammonium halides

Plastic crystals as barocaloric materials exhibit the large entropy change rivalling freon, however, the limited pressure-sensitivity and large hysteresis of phase transition hinder the colossal barocaloric effect accomplished reversibly at low pressure. Here we report reversible colossal barocaloric effect at low pressure in two-dimensional van-der-Waals alkylammonium halides. Via introducing long carbon chains in ammonium halide plastic crystals, two-dimensional structure forms in (CH3–(CH2)n-1)2NH2X (X: halogen element) with weak interlayer van-der-Waals force, which dictates interlayer expansion as large as 13% and consequently volume change as much as 12% during phase transition. Such anisotropic expansion provides sufficient space for carbon chains to undergo dramatic conformation disordering, which induces colossal entropy change with large pressure-sensitivity and small hysteresis. The record reversible colossal barocaloric effect with entropy change ΔSr ~ 400 J kg−1 K−1 at 0.08 GPa and adiabatic temperature change ΔTr ~ 11 K at 0.1 GPa highlights the design of novel barocaloric materials by engineering the dimensionality of plastic crystals.

Catalyzing Desolvation at Cathode-Electrolyte Interface Enabling High-Performance Magnesium-Ion Batteries.

Magnesium ion batteries (MIBs) are expected to be the promising candidates in the post-lithium-ion era with high safety, low cost and almost dendrite-free nature. However, the sluggish diffusion kinetics and strong solvation capability of the strongly polarized Mg2+ are seriously limiting the specific capacity and lifespan of MIBs. In this work, catalytic desolvation is introduced into MIBs for the first time by modifying vanadium pentoxide (V2O5) with molybdenum disulfide quantum dots (MQDs), and it is demonstrated via density function theory (DFT) calculations that MQDs can effectively lower the desolvation energy barrier of Mg2+, and therefore catalyze the dissociation of Mg2+-1,2-Dimethoxyethane (Mg2+-DME)bonds and release free electrolyte cations, finally contributing to a fast diffusion kinetics within the cathode. Meanwhile, the local interlayer expansion can also increase the layer spacing of V2O5 and speed up the magnesiation/demagnesiation kinetics. Benefiting from the structural configuration, MIBs exhibit superb reversible capacity (≈300mAhg-1 at 50mAg-1) and unparalleled cycling stability (15 000 cycles at 2Ag-1 with a capacity of ≈70mAhg-1). This approach based on catalytic reactions to regulate the desolvation behavior of the whole interface provides a new idea and reference for the development of high-performance MIBs.

Effective intercalation of [Ru(bpy)3]2+ into titania nanosheet films using bipyridinium analogs as intermediate guests

Abstract The intercalation of a large photofunctional molecule, tris(bipyridine)ruthenium (II) ([Ru(bpy)3]2+), into titania nanosheet (TNS) films via a guest-exchange method was investigated using 6 bipyridinium analogs as intermediate guest (IG) molecules. The interlayer distance of the IG intercalated TNS films affects the subsequent ion-exchange reaction and the adsorption rate of [Ru(bpy)3]2+. The IG 3,3′-diethylbipyridinium (3-Etbpy2+) was as the most effective interlayer expansion molecule among the studied analogs.

Interlayer spacing expansion for V2O5 towards ultra-stable zinc anode-based flexible electrochromic displays in Zn2+/Li+-PC organic electrolyte

To enhance the electrochemical stability and kinetics of V2O5, 3,4-ethylenedioxythiophene (EDOT) was in-situ polymerized within V2O5 interlayers, rendering PEDOT@V2O5 with enlarged layer spacing, increased stability in organic electrolyte, superior electrochemical...

Selenium doping induced phase transformation and interlayer expansion boost the zinc storage performance of molybdenum disulfide

This work synthesized Se-doped MoS2 nanosheets as a cathode for aqueous zinc-ion batteries, and they exhibited largely improved electrochemical performance owing to their high content of the 1T phase (64%) and expanded interlayer spacing (0.65 nm).