Weak Binding Strength Research Articles

Unconventional Electrocatalytic CO Conversion to C2 Products on Single-Atomic Pd-Agn Sites.

The electrochemical reduction of CO or CO2 into C2+ products has mostly been focused on Cu-based catalysts. Although Ag has also been predicted as a possible catalyst for the CO-to-C2+ conversion from the thermodynamic point of view, however, due to its weak CO binding strength, CO rapidly desorbs from the Ag surface rather than participates in deep reduction. In this work, we demonstrate that single-atomic Pd sites doped in Ag lattice can tune the CO adsorption behavior and promote the deep reduction of CO toward C2 products. The monodispersed Pd-Agn sites enable the CO adsorption with both Pd-atop (PdL) and Pd-Ag bridge (PdAgB) configurations, which can increase the CO coverage and reduce the C-C coupling energy barrier. Under room temperature and ambient pressure, the Pd1Ag10 alloy catalyst exhibited a total CO-to-C2 Faradaic efficiency of ~37 % at -0.83 V, with appreciable current densities and electrochemical stability, thus featuring unconventional non-Cu electrocatalytic CO-to-C2 conversion capability.

Unconventional Electrocatalytic CO Conversion to C2 Products on Single‐Atomic Pd−Agn Sites

AbstractThe electrochemical reduction of CO or CO2 into C2+ products has mostly been focused on Cu‐based catalysts. Although Ag has also been predicted as a possible catalyst for the CO‐to‐C2+ conversion from the thermodynamic point of view, however, due to its weak CO binding strength, CO rapidly desorbs from the Ag surface rather than participates in deep reduction. In this work, we demonstrate that single‐atomic Pd sites doped in Ag lattice can tune the CO adsorption behavior and promote the deep reduction of CO toward C2 products. The monodispersed Pd−Agn sites enable the CO adsorption with both Pd‐atop (PdL) and Pd−Ag bridge (PdAgB) configurations, which can increase the CO coverage and reduce the C−C coupling energy barrier. Under room temperature and ambient pressure, the Pd1Ag10 alloy catalyst exhibited a total CO‐to‐C2 Faradaic efficiency of ~37 % at −0.83 V, with appreciable current densities and electrochemical stability, thus featuring unconventional non‐Cu electrocatalytic CO‐to‐C2 conversion capability.

Unlocking the Potential for Methanol Synthesis via Electrochemical CO2 Reduction Using CoPc-Based Molecular Catalysts.

The electrochemical CO2 reduction reaction (CO2RR) to produce methanol (CH3OH) is an attractive yet challenging approach due to a lack of selective electrocatalysts. An immobilized cobalt phthalocyanine (CoPc) molecular catalyst has emerged as a promising electrocatalyst for CH3OH synthesis, demonstrating decent activity and selectivity through a CO2-CO-CH3OH cascade reaction. However, CoPc's performance is limited by its weak binding strength toward the CO intermediate. Recent advancements in molecular modification aimed at enhancing CO intermediate binding have shown great promise in improving CO2-to-CH3OH performance. In this Perspective, we discuss the competitive binding mechanism between CO2 and CO that hinders CH3OH formation and summarize effective molecular modification strategies that can enhance both the binding of the CO intermediate and the conversion of the CO2-to-CH3OH activity. Finally, we offer future perspectives on optimization strategies to inspire further research efforts to fully unlock the potential for methanol synthesis via the CO2RR using molecular catalysts.

The strategy of micropore confinement via organic macrocyclic cavities for designing novel high-performance proton exchange membranes

The high-temperature hydrogen proton exchange membrane fuel cell is considered a disruptive technology for future energy applications. However, the weak binding strength between the proton carriers (phosphoric acid molecules) with polymer chains reduces the operational stability and proton transfer efficiency at conditions of high temperature and low humidity. In this work, a strategy of micropore confinement via organic macrocyclic cavities (sulfonic calix[4]arenes, sulfonic calix[8]arenes, sulfonated β-cyclodextrin) was developed for designing novel mixed matrix membranes functioning as high-temperature hydrogen proton exchange membranes. Benefitting from the confined micropores constructed by supramolecular cavities, the obtained mixed matrix membranes showed a higher uptake and retention capability of phosphoric acid as well as lower membrane swelling, yielding an enhanced proton conductivity. The proton conductivity of the mixed matrix membranes was 2–3 times higher while the conductivity attenuation was only 58.6% comparing with neat PBI membrane, (140℃, relative humidity = 0). In addition, due to the good compatibility caused by hydrogen bonding between fillers and polymer chains, the volume swelling was only 14% and the mechanical strength of the obtained mixed matrix membranes increased. We believe the strategy of micropore confinement via organic macrocyclic cavities for designing the novel mixed matrix membranes is thought to be of great significance for the research on high-temperature proton exchange membrane.

Application of vertically ordered polyaniline nanofibers in enhancing the ORR activity of Pt catalysis

Pt-based nanocatalysts supported on carbon materials have exhibited remarkable catalytic activity in the oxygen reduction reaction (ORR). However, these catalysts still encounter challenges such as low utilization efficiency, weak binding strength with substrate and proneness to detachment from it. Consequently, we explore the potential application of electron-rich polymer as carrier in high efficiency ORR catalysts, the uniformly distributed Pt-PANI catalyst is successfully synthesized by taking advantage of ion-exchange property of polyaniline (PANI). As an emerging catalyst for ORR, Pt-PANI shows excellent ORR performance in acidic solution, the vertically aligned PANI nanoarrays accelerate the ion diffusion in electrolyte and promote the charge transfer at the interface, improving the catalytic activity of low-loading Pt-based catalyst. In short, this work provides a novel alternative beyond conventional carbonaceous materials for the selection of carriers for Pt-based catalyst.

Metal-ion-determined geometrical configurations of metallo-cages with different emission properties.

The formation of metallo-cages is affected by a variety of factors such as the ligands, metals, and anions, among which the impact of metals with different binding capacities is particularly important, but has rarely been studied in three-dimensional metallo-cages. Herein, we report the design of truxene-centered terpyridine ligands and the self-assembly of a series of tetrameric metallo-cages. The utilization of metal ions with strong (Zn2+, Fe2+) or weak (Cd2+) binding strength afforded 3D metallo-cages with low symmetry or highly symmetric metallo-tetrahedra, respectively, possessing totally different geometrical configurations. In addition, their photophysical properties and host-guest chemical properties were investigated.

In vitro interactions of two pesticides, propazine and quinoxyfen with bovine serum albumin: Spectrofluorometric and molecular docking investigations

Binding mechanisms of two selected pesticides, propazine (PRO) and quinoxyfen (QUI) with bovine serum albumin (BSA) was examined using fluorescence, absorption and molecular docking methods. Intrinsic fluorescence of BSA was quenched in the presence of both PRO and QUI. The quenching was ascertained to be conversely linked to temperature, which suggested the contribution of static quenching process in the PRO–BSA and QUI–BSA complex formations. This results were validated by the enhancement in absorption spectrum of BSA upon binding with PRO and QUI. Binding constant values (Kf = 9.55–0.60 × 10–3 M−1 for PRO–BSA system; Kf = 7.08–5.01 × 102 M−1 for QUI–BSA system) and number of binding site (n) values for the PRO–BSA and QUI–BSA systems at different temperatures affirmed a weak binding strength with a set of equivalent binding sites on BSA. Thermodynamic data obtained for both the PRO–BSA and QUI–BSA interactions predicted that the association process was spontaneous and non-covalent contacts such as hydrophobic interactions, van der Waals forces and hydrogen bonds participated in the binding reactions. This result was further supported by the molecular docking assessments. Three-dimensional spectral results revealed the microenvironmental alterations near tryptophan (Trp) and tyrosine (Tyr) residues in BSA by the addition of PRO and QUI. The docking analysis demonstrated the binding pattern for the PRO–BSA and QUI–BSA systems and disclosed the preferred binding site of both PRO and QUI as site I (subdomain IIA) of BSA.

Self-Accommodation Induced Electronic Metal-Support Interaction on Ruthenium Site for Alkaline Hydrogen Evolution Reaction.

Tuning the metal-support interaction of supported metal catalysts has been found to be the most effective approach to modulating electronic structure and improving catalytic performance. But practical understanding of the charge transfer mechanism at the electronic level of catalysis process has remained elusive. Here, it is reported that ruthenium (Ru) nanoparticles can self-accommodate into Fe3 O4 and carbon support (Ru-Fe3 O4 /C) through the electronic metal-support interaction, resulting in robust catalytic activity toward the alkaline hydrogen evolution reaction (HER). Spectroscopic evidence and theoretical calculations demonstrate that electronic perturbation occurred in the Ru-Fe3 O4 /C, and that charge redistribution directly influenced adsorption behavior during the catalytic process. The RuO bond formed by orbital mixing changes the charge state of the surface Ru site, enabling more electrons to flow to H intermediates (H* ) for favorable adsorption. The weak binding strength of the RuO bond also reinforces the anti-bonding character of H* with a more favorable recombination of H* species into H2 molecules. Because of this satisfactory catalytic mechanism, the Ru-Fe3 O4 /C supported nanoparticle catalyst demonstrated better HER activity and robust stability than the benchmark commercial Pt/C benchmark in alkaline media.

Tetrel-Bond Interactions Involving Metallylenes TH2 (T = Si, Ge, Sn, Pb): Dual Binding Behavior.

The dual binding behavior of the metallylenes TH2 (T = Si, Ge, Sn, Pb) with some selected Lewis acids (T'H3F, T' = Si, Ge, Sn, Pb) and bases (N2, HCN, CO, and C6H6) has been investigated by using the high-level quantum chemical method. Two types (type-A and type-B) of tetrel-bonded complexes can be formed for TH2 due to their ambiphilic character. TH2 act as Lewis bases in type-A complexes, and they act as Lewis acids in type-B ones. CO exhibits two binding modes in the type-B complexes, one of which is TH2···CO and the other is TH2···OC. The TH2···OC complexes possess a weaker binding strength than the other type-B complexes. The TH2···OC complexes are referred to as the type-B2 complexes, and the other type-B complexes are referred to as the type-B1 complexes. The type-A complexes exhibit a relatively weak binding strength with Eint (interaction energy) values ranging from -7.11 to -15.55 kJ/mol, and the type-B complexes have a broad range of Eint values ranging from -9.45 to -98.44 kJ/mol. The Eint values of the type-A and type-B1 complexes go in the order SiH2 > GeH2 > SnH2 > PbH2. The AIM (atoms in molecules) analysis suggests that the tetrel bonds in type-A complexes are purely closed-shell interactions, and those in most type-B1 complexes have a partially covalent character. The EDA (Energy decomposition analysis) results indicate that the contribution values of the three energy terms go in the order electrostatic > dispersion > induction for the type-A and type-B2 complexes, and this order is electrostatic > induction > dispersion for the type-B1 complexes.

Achieving reaction pathway separation for electrochemical nitrate fixation on triatomic catalysts: A new mechanism

As the continuous development of electrocatalytic technique, the degradation of toxic nitrate wastewater into green fuel ammonia has become the goal of researcher’s unremitting efforts by electrochemical method. Particularly, a high performance catalyst for electrochemical process is regarded as an indispensable tool for sustainable cycle. Although existing designed electrodes may effectively advance nitrate reduction reaction, they remain unsatisfactory due to elusive reaction processes. Here, a brand-new reaction mechanism has been proposed via density functional theory (DFT) and ab initio molecule dynamic (AIMD) methods, which breaks the bottleneck of linear scaling in atomic scale catalyst design. It is found that triple Mn atoms anchored on graphdiyne (Mn 3 -GDY) can drive nitrate adsorption and ammonia desorption on its surface with weak binding strength and strong activation by the spin polarization of active site. In addition, the powerful adsorption capacity of triatomic active site prevents the thermodynamic barrier from rising due to the transformation of the intermediates *NO 3 H and *NO 2 H into *NO 2 *OH and *NO*OH, respectively. More importantly, in accordance with the “weak-strong-weak” principle, Mn 3 -GDY has rapid response to ammonia desorption that is conducive to boost the turnover frequency. Anyway, this work may provide a new insight into atomic catalysts for improving reaction mechanisms. • Electrocatalytic reduction of nitrate into ammonia is realized on triatomic catalysts • A new mechanism breaks the bottleneck of linear scaling in atomic catalyst design • This mechanism perfectly matches the “weak-strong-weak” design principles • Mn 3 -GDY is an excellent candidate for NO 3 RR with an low limiting potential of 0.23 V

Multiplexed evaluation of immunity against SARS-CoV-2 variants using surface enhanced fluorescence from a nanostructured plasmonic chip

Generated by the immune system post-infection or through vaccination, the effectiveness of antibodies against emerging SARS-CoV-2 variants is crucial for protecting individuals from the COVID-19 pandemic. Herein, a platform for the multiplexed evaluation of SARS-CoV-2 neutralizing antibodies against various variants was designed on the basis of near-infrared (NIR) surface enhanced fluorescence by nano-plasmonic gold chip (pGOLD). Antibody level across variants (Wild-type, Alpha, Beta, Delta, Omicron) was confirmed by the sera from recovered-individuals who were unvaccinated and had infected with Wild-type, Delta, Omicron variants. However, the neutralizing activity against Omicron variant was markedly decreased for individuals infected by Wild-type (~ 5.6-fold) and Delta variant (~ 19.1-fold). To the opposite, neutralizing antibody from individuals recovered from Omicron variant infection showed weak binding strength against non-Omicron variants. Antibody evolution over time was studied with individuals 196–530 days post Wild-type infection. Decreasing IgG antibody titer accompanied by increasing IgG binding avidity with elongated post-infection period were observed for the sera from Wild-type recovered-individuals with different post-infection times, suggesting that after the primary infection, a great number of antibodies were generated and then gradually decreased, while the antibody matured over time. By comparing the IgG level of individuals vaccinated for 27–51 days with individual post-infection, we found that ca. 1 month after two doses of vaccination, the antibody level was comparable to that of 500 days post-infection, and vaccination could enhance IgG avidity more efficiently. This work demonstrated a platform for the multiplexed, high-throughput and rapid screening of acquired immunity against SARS-CoV-2 variants, providing a new approach for the analysis of vaccine effectiveness, immunity against emerging variants, and related serological study.Graphical

Dynamics of protein condensates in weak-binding regime.

Weak complementary interactions between proteins and nucleic acids are the main driving forces of intracellular liquid-liquid phase separation. The sticker-spacer model has emerged as a unifying principle for understanding the phase behavior of these multivalent molecules. It remains elusive how specific interactions mediated by stickers contribute to the rheological properties of the liquid condensates. Previous studies have revealed that for strong binding strength ɛ_{b}, the bulk diffusivity D depends on the effective bond lifetime τ, viz., D∝τ^{-1}. Consequently, equal concentrations of the complementary stickers induce a slow down in the dynamics of the condensates D∝e^{-1.5ɛ_{b}}. However, for weak-binding strength, it is expected that the resulting condensates are dynamic, loose network liquids rather than kinetically arrested, compact clusters. We develop a mean-field theory using the thermodynamics of the associative polymers and perform molecular-dynamics simulations based on the sticker-spacer model to study the controlling factors in the structure and dynamics of such condensates in the weak-binding regime. Through scaling analysis, we delineate how the free sticker fraction W_{f} and the bulk diffusivity D decrease with increasing binding energy and find that the internal dynamics of such network liquids are controlled by the free sticker fraction D∝W_{f}∝e^{-0.5ɛ_{b}} rather than the effective bond lifetime. Referred to as the free-sticker-dominated diffusivity, the microscopic slowdown due to a gradual loss of the free stickers affects the viscosity of the condensates as well, with the scaling of the zero-shear viscosity η∝e^{0.5ɛ_{b}}. Therefore, the way of controlling the structure, diffusivity, and viscosity of the condensates through the binding energy can be tested experimentally.

Surface modified hollow glass microspheres-epoxy composites with enhanced thermal insulation and reduced dielectric constant

The hollow glass microspheres (HGMs) are the important fillers in the thermal insulating composites due to the low density, high flowability and the low thermal conductivity. However, the high filling ratio of HGMs without phase separation is hard to be reached owing to the weak interface binding strength between the HGMs and the resin matrix in the composites. In this work, the surface of HGMs is modified with silane coupling agents (3-Glycidoxypropyltrimethoxysilane, KH560) to improve the interface binding strength. After the surface modification, the maximum filling ratio of the HGMs in the epoxy (EP) resin can reach 35 wt. % (67 vol. %). The highly improved filling ratio benefits the HGMs-EP composites with an improved thermal insulation with a low thermal conductivity 0.14 W·m−1·K−1. Moreover, a highly reduced permittivity Dk = 2.3 at the frequency of 110 MHz is also attained for the 67 vol. % HGMs filled composites, which should be promising for the 5G communication technology that requires low dielectric constant for reducing the signal delay and loss.

Highly durable ZIF-8 tubular membranes via precursor-assisted processing for propylene/propane separation

ZIF-8 membrane has been considered as a potential alternative to the traditional cryogenic distillation process for propylene/propane (C3H6/C3H8) separation. However, the scale-up preparation and stability of ZIF-8 membranes are limited by the weak binding strength between membrane and tubular support. Herein, we report a precursor-assisted processing method that featured strong binding strength at the interface of ZIF-8 membranes and tubular supports. ZIF-8 tubular membranes are then assembled into a membrane module with an effective membrane area of about 157 cm2 for efficient C3H6/C3H8 separation. Reliable binding strength is achieved and maintained over 10 min sonication which results in remarkable operation stability over 30 days. The C3H6 permeance and separation factor of this membrane module reached 1.08 × 10−8 mol m−2 s−1 Pa−1 and 55 at 60 °C and 0.7 MPa, with purity and productivity of 98.3% and 6.2 × 10−5 mol s−1, respectively. The good repeatability and durability of the ZIF-8 tubular membrane module demonstrate its potential for further scale-up towards practical application.

Synergistic bonding stabilized interface for perovskite solar cells with over 24% efficiency

Planar-type perovskite solar cells have attracted extensive attentions due to their simple architecture and manufacturing. However, an imperfect heterojunction at the electron-selective contact side with abundant detrimental defects and weak binding strength induces severe charge recombination and device instability during long-term operation, which seriously hinders the further development and application prospect. Herein, we demonstrate π-conjugated oxysalt as an efficient interfacial binder and defect passivator for the stabilization of SnO2/perovskite interface. Theoretical modeling and experimental studies confirm the synergistic effect of ionic bonding and π-cation interaction in reducing defect density and mitigating charge recombination. An impressive power conversion efficiency up to 24.05%, a fill factor as high as 84.52%, and negligible hysteresis can be achieved in optimized solar cell. π-conjugated oxysalt interlayer can also improve device stability by offering a robust interface. Our work highlights the significance of chemical bonding engineering in constructing a high-quality heterojunction for efficient and stable perovskite solar cells.

A DFT Study on the Activity Origin of Fe-N-C Sites for Oxygen Reduction Reaction.

Iron-nitrogen-carbon materials have been known as the most promising non-noble metal catalyst for proton-exchange membrane fuel cells (PEMFCs), but the genuine active sites for oxygen reduction reaction (ORR) are still arguable. Herein, by the thorough density functional theory investigations, we unravel that the planar Fe2 N6 site exhibits excellent ORR catalytic activity over both FeN3 and FeN4 sites, and the potential-determining step is determined to be the *OH hydrogenation step with an overpotential of 0.415 V. The ORR activity of Fe2 N6 site originates from the low spin magnetic moment (1.11 μB ), which leads to high antibonding states and low d-band center of the Fe center, further leads to weak binding strength of *OH species. The density of FeN4 sites only has little influence on the ORR activity owing to the similar interaction between active site and intermediates in ORR. Our research sheds light on the activity origin of iron-nitrogen-carbon materials for ORR.

Structure-dependent of 3-fluorooxindole derivatives interacting with ctDNA: Binding effects and molecular docking approaches

3-Fluorooxindole has been shown to be a biologically active structural unit, novel derivative containing 3-fluorooxindole unit has been successfully constructed using 3-fluorooxindole as a substrate in previous work. Here, the interactions between novel 3-fluorooxindole derivatives and ctDNA were explored through molecular docking, multi-spectral and NMR methods, and the dependence of the binding mechanism on the structure was revealed by combined physical chemistry and organic chemistry. Firstly, molecular docking indicated that the planarity of the molecule enhances the binding strength to ctDNA. UV absorption result showed a weak binding effect. Fluorescence spectroscopy suggested the binding mechanism of 3-fluorooxindoles and ctDNA via groove binding. Moreover, the binding mechanism of 3-fluorooxindoles to ctDNA was further confirmed by 1H NMR spectroscopy, viscometry, and CD spectroscopy as groove binding. FT-IR spectroscopy reflected a more obvious disturbance of the phosphate group in the groove region of ctDNA. Electrochemistry was also used to probe the binding strength of 3-fluorooxindoles to ctDNA, and it showed a weak binding strength. From the above study, we concluded that 3-fluorooxindoles bind mainly in the groove region of ctDNA with weak binding strength. This study provides an idea for the activity screening aspect of 3-fluorooxindole derivatives from molecular planarity consideration and relevant information on biophysical and bioorganic aspects for drug development.

Recent biomedical advances enabled by HaloTag technology

The knowledge of interactions among functional proteins helps researchers understand disease mechanisms and design potential strategies for treatment. As a general approach, the fluorescent and affinity tags were employed for exploring this field by labeling the Protein of Interest (POI). However, the autofluorescence and weak binding strength significantly reduce the accuracy and specificity of these tags. Conversely, HaloTag, a novel self-labeling enzyme (SLE) tag, could quickly form a covalent bond with its ligand, enabling fast and specific labeling of POI. These desirable features greatly increase the accuracy and specificity, making the HaloTag a valuable system for various applications ranging from imaging to immobilization of POI. Notably, the HaloTag technique has already been successfully employed in a series of studies with excellent efficiency. In this review, we summarize the development of HaloTag and recent advanced investigations associated with HaloTag, including in vitro imaging (e.g., POI imaging, cellular condition monitoring, microorganism imaging, system development), in vivo imaging, biomolecule immobilization (e.g., POI collection, protein/nuclear acid interaction and protein structure analysis), targeted degradation (e.g., L-AdPROM), and more. We also present a systematic discussion regarding the future direction and challenges of the HaloTag technique.

Sustainable Fenton-like degradation of methylene blue over MnO2-loaded poly(amidoxime-hydroxamic acid) cellulose microrods

Catalysts based on cellulose/metal oxide hybrids are considered effective for the remediation of dye wastewater. However, the difficult recovery of commonly used nanocellulose and the weak binding strength of metal oxide nanoparticles restrict their wide application. Herein, MnO2 nanoparticle-loaded poly(amidoxime-hydroxamic acid) modified microcrystalline cellulose (pAHA-MCC@MnO2) catalysts were synthesized via an oximation reaction followed by in-situ growth. Morphology, crystallinity and textural characteristics of pAHA-MCC before and after deposition of MnO2 nanoparticles were characterized by SEM, EDS, FTIR, XRD and XPS analyses. The main results indicated the formation of hierarchical porous structured cellulose microrods with uniform distribution of hydrangea flower-like MnO2 nanoparticles. In the presence of H2O2, pAHA-MCC@MnO2 displayed good catalytic performance toward the degradation of methylene blue (MB) over a wide pH range of 3–10, due to the advanced Fenton-like catalysis. Reaction conditions, such as amount of H2O2 used, the initial MB concentration and catalyst dosage were also investigated. The optimized system showed 97.6% removal of MB in 25 min for 100 mg/L MB solution, with very little decrease in performance after 5 cycles. This work provides a facile and promising strategy for the development of biodegradable and sustainable architectures capable of efficiently degrading dye wastewater.

High‐capacity anode derived from graphene oxide with lithium‐active functional groups

Applications utilizing Li-ion batteries (LIBs) have recently been broadened from portable electronic devices to electric vehicles. Graphite has been applied as an anode material for commercialized LIBs; however, there is a growing demand for application-oriented LIBs with higher energy and power densities, and faster charging, compared with its limited electrochemical properties. Heteroatom-doped graphene has been considered as a potential alternative to graphite, although its synthesis is complex and costly. In this study, we introduced a facile strategy to realize advanced anode materials through fine control of the sheet size and oxygen-containing functional groups on the surface of graphene oxide (GO) as a raw material for heteroatom-doped graphene. The sheet size of GO is inversely proportional to the amount of oxidizing agent, which affects the formation of various types of oxygen-containing functional groups at the edges of GO. Mild annealing of GO selectively removes the functional groups with weak binding strength, leading to the formation of GO maximized with carbonyl groups, which can interact with Li ions quickly and reversibly. The GO with the average sheet size of 500 nm developed in this study exhibits capacities of up to 779 and 220 mAh g−1 at 0.1 and 2 A g−1, respectively. Therefore, decreasing the sheet size of GO with mild-temperature annealing increases the number of carbonyl groups formed on the additional exposed edge of the sheets, resulting in facile Li-ion interaction and a higher capacity as an anode material.