Ti3C2 MXene Research Articles

Scalable synthesis of 2D-layered Ti3C2 MXene by HF etching method; electrochemical investigations and device fabrication to enhancing capacitive nature

The goal of the current effort is aimed to synthesise the uniform exfoliated titanium carbide (Ti3C2) MXene sheets by utilising hydrofluoric (HF) acid to remove/etch “aluminium” from the parental Ti3AlC2 MAX phase. The Ti3C2 MXene was investigated by structural analysis using X-ray diffraction (XRD), Higher Resolution Transmission Electron Microscope (HRTEM), Scanning electron microscope (SEM), and EDS with mapping for morphological and elemental analysis, Moreover, the Ti3C2 MXene was studied its electrochemical properties to electrochemical energy storage application using cyclic voltammetry (CV), Galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. Since the GCD analysis of Ti3C2 MXene, a great specific capacitance (Csp) of 318F/g was attained with current density of 1 A/g and up to 90 % retentivity was attained after 7500 cycles. Besides, fabricated Ti3C2 MXene||Ti3C2-MXene symmetric supercapacitor device (SSD) has described the energy density (ED) of 27.78 Wh/kg at a power density (PD) of 400 W/kg and the capacitive retention existed attained 92.1 % after 7500 cycles with 5 A/g.

High performance Cu/SAC305 solder low temperature bonding using Ti3C2 MXene interlayer

Ti3C2 MXene (MX) was introduced as the interlayer between the Cu film and Sn-3.0Ag-0.5Cu (SAC) solder to inhibit the overgrowth of intermetallic compounds (IMCs) at the bonding interface of Cu and SAC solder. The Cu-MX-SAC bonding was fabricated at 160 °C for 6 mins under a load of 10 MPa. Compared with Cu-SAC bonding, after 72 h aging, the average thickness of the IMCs layer in the Cu-MX-SAC structure is about 47 % thinner. As aging time increases, the diffusion rate of Cu atoms is limited due to the introduction of MXene interlayer, and the growth of IMCs in the Cu-MX-SAC structure is controlled by volume diffusion. For the Cu-MX-SAC solder bonding, after prolonged aging, the shear strength increases, and contact resistance at the bonding interface is almost no change compared with Cu-SAC solder bonding.

First principles insights into triboelectrification during solid-solid contact: The curious case of 2D MXenes and aluminum

Recently, triboelectric nanogenerators (TENGs) have been widely used for energy harvesting and self-powered sensing due to their significant and unique advantages. However, the intrinsic mechanisms that contribute to tribo-electricification (TE) between two materials remain as a subject of rigorous debate. In addition to predicting the qualitative charge transfer in solid-solid contacts based on the difference in the work functions of the two moieties constituting the interface, we argue that it is essential to obtain atomic-level, first principles, insights into the bonding properties, quantitative charge transfer, and the possible presence of a electrostatic potential barrier at the interface to fully understand the TE mechanism of a system. We have utilized dispersion-corrected density functional theory (DFT) calculations in this study to systematically investigate the TE potential of bare surface Ti3C2 and Ti3N2 2D MXene monolayers and their surface functionalized modifications Ti3C2R2 and Ti3N2R2 (where R = -O, -OH, or -F) in contact with Al(111). For these heterostructures, we have analyzed the adhesive energy of the interfaces, the nature of interaction through the electron localization function (ELF), and the charge distribution, which have revealed distinct characteristics of MXene/Al contacts for these monolayer/metal interfaces at their equilibrium distance and the changes in their properties under uniaxial pressure. Among all the metallic 2D MXene variants investigated in this study, we have determined that Ti3C2F2/Al and Ti3N2F2/Al interfaces show exceptional potential for TE.

Ti3C2 MXene nanosheets integrated cobalt-doped nickel hydroxide heterostructured composite: An efficient electrocatalyst for overall water-splitting

Developing an efficient electrocatalyst for superior electrochemical water splitting (EWS) is crucial for achieving comprehensive hydrogen production. A heterostructured electrocatalyst, free of noble metals, Ti3C2 MXene nanosheet-integrated cobalt-doped nickel hydroxide (NHCoMX) composite was synthesized via a hydrothermal method. The abundant pores in the Ti3C2 MXene nanosheet (MX)–integrated microarchitecture increased the number of active sites and facilitated charge transfer, thus enhancing electrocatalysis. Specifically, the MX-enhanced charge transfer considerably transformed the microelectronic structure of cobalt-doped Ni(OH)2 (NHCo), which promoted its hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Hence, as an EWS catalyst, NHCoMX exhibited an exceptional electrocatalytic activity, demonstrating OER and HER overpotentials of 310 mV and 73 mV, respectively, with low Tafel slopes of 65 mV dec−1 and 85 mV dec−1, respectively; it exhibited a current density of 10 mV cm−2 in 1.0 mol L−1 KOH, representing the closest efficiency to the noble state-of-the-art RuO2 and Pt/C catalyst. Furthermore, the developed electrocatalyst improved the activities of both HER and OER, leading to an overall EWS current density of 10 mA cm−2 at 1.72 V in an alkaline electrolyte with two electrodes. This study describes an efficient heterostructured NHCoMX composite electrocatalyst. It is significantly comparable to the noble state-of-the-art electrocatalysts and can be extended to fabricate resourceful catalysts for large-scale EWS applications.

Electrophoretic deposition of MXene coating on Mg alloy 2,5 PDCA-LDH film for enhanced anticorrosion/wear

Two-dimensional (2D) MXene, employed as protective coatings for anticorrosion and wear resistance, outperforms most state-of-the-art 2D nanomaterials. In this work, MgAl-LDH film modified with the 2,5 PDCA inhibitor was synthesized on Mg alloy AZ31 via in-situ hydrothermal methods. Subsequently, MXene Ti3C2 at various concentrations was electrophoretically deposited onto the as-prepared 2,5 PDCA-LDH film. The successful incorporation of the 2,5 PDCA inhibitor resulted in MgAl-LDH nanosheets with a low growth angle, facilitating the electrophoretic deposition of MXene Ti3C2. After deposition, Ti3C2 nanomaterials uniformly coated the 2,5 PDCA-LDH film, forming a protective barrier against corrosive species while simultaneously establishing a lubricating layer. Notably, Ti3C2 nanosheets exhibit a tendency to self-agglomerate at higher concentrations, resulting in the 1.0 wt% Ti3C2 coating displaying the highest anticorrosion and lubrication capacities.

Microwave-assisted PMS activation Ti3C2/LaFe0.5Cu0.5O3-P catalysts for efficient degradation of CIP: Enhancement of catalytic performance by phosphoric acid etching

The LaFe0.5Cu0.5O3 perovskite synthesised by MOFs template method was compounded with Mxene Ti3C2, and the novel catalyst M-Ti3C2/LFCO-P was subsequently prepared by phosphoric acid etching. This catalyst effectively induced microwave activation of peroxymonosulfate (PMS), and ciprofloxacin (CIP) was efficiently degraded with a degradation rate reaching 95.48 % within 14 min. Characterization results revealed that the MOFs template method and phosphoric acid etching increased specific surface area (from 25.91 m2/g to 142.41 m2/g) of catalyst and improved its pore size distribution. Phosphoric acid etching successfully introduced phosphorus functional groups and promoted the formation of more oxygen vacancies, thereby significantly enhancing the catalytic activity of the catalyst. The conversion of free radicals and the transformation of free radicals to non-free radicals were demonstrated. Additionally, the catalyst exhibited higher electron transfer efficiency. The catalytic reaction was primarily driven by O2– and 1O2, with OH, SO4−, and e- playing auxiliary roles. Furthermore, the degradation pathway and toxicity of CIP were also evaluated. This work provides a new perspective for improving the catalytic degradation activity of antibiotics by perovskite catalysts.

Sandwiched heterostructure of NiFe2O4/TiO2 nanocrystals and MXene nanosheets for highly active oxygen electrocatalyst in rechargeable zinc-air batteries

Recent advancements in zinc-air batteries (ZABs) emphasize the need for efficient and sustainable oxygen electrocatalysts. Central to these efforts are metal-organic frameworks (MOFs), renowned for their bifunctional oxygen electrocatalytic capabilities. However, MOFs and their derivatives often exhibit subpar electrical conductivity and stability. Addressing this, we introduce an innovative approach involving MOFs-derived NiFe2O4/TiO2 nanocrystals sandwiched between 2D MXene nanosheets. This hybrid structure, NiFe2O4/TiO2@NC/Ti3C2, successfully enhances conductivity and active site accessibility, thereby enhancing oxygen reduction (ORR) and evolution (OER) reactions. The NiFe2O4/TiO2@Ti3C2–2 hybrid demonstrates excellent bifunctional activity, characterized by a notable ORR's half-wave potential of 0.846 V and an OER's onset potential of 1.5 V with a potential gap (ΔE) of 0.75 V. When employed in a ZAB, the battery achieves a peak power density of 164 mW cm−2 and maintains cycling stability for over 500 h at 10 mA cm−2. Beyond serving as conductive scaffolds, Ti3C2 MXene nanosheets have a vital role in preserving surface areas of the NiFe2O4/TiO2@NC materials. This study not only highlights a successful strategy for improving oxygen reactions in ZABs but also opens up new opportunities for the development of advanced MOF@MXene catalysts in energy conversion applications.

Oxygen vacancy mediated photocatalysis of Ti3C2 MXene quantum dots/W18O49 hybrid membrane for peroxymonosulfate-enhanced oxidation degradation

Photocatalytic membrane technology shows great prospects in water decontamination. Coupling photocatalysis with peroxymonosulfate (PMS) can boost oxidation capacity by combining their superiorities sufficiently. Herein, 0D Ti3C2 MXene quantum dots (TMQDs) embedded oxygen vacancy-rich 3D sea urchin-like W18O49 microspheres (OTW) were synthesized via facile interface engineering combined with green plasma etching strategy. The visible-light driving flow-through membrane reactor was capable of degrading cyclophosphamide, a typical anticancer drug, and other common pollutants (5-fluorouracil, carbamazepine, bisphenol A, rhodamine B), with the removal and mineralization efficiencies of 10 μM pollutants reaching over 99 % and 63 %−79 % in 60 min with 0.5 mM PMS. Moreover, the long-term reliability of OTW membrane was validated through continuous treatment of 20 L sewage. Significantly, the newly designed photocatalytic membrane exhibited good tolerance to wide pH ranges, common coexisting substances in water, and various actual water matrix. The results of experimental and DFT theoretical calculations revealed that Schottky junction formed on the TMQDs/W18O49 interfaces and tunable O-defects could optimize electronic configuration, improve solar energy utilization, prevent photogenerated carriers’ recombination, promote H2O and PMS dissociation, making it possible that more •OH and SO4•− radicals participated in the oxidation degradation reaction. This study offers a design idea for preparing efficient and robust photocatalytic membrane via interface engineering and defect engineering strategies, which might contribute to bridging the translational gap between emerging photocatalytic techniques and practical environmental applications in near future.

InVO4-Decorated Ti3C2 MXene for Efficient Photocatalytic Hydrogen Evolution.

The generation of hydrogen through photocatalysis is a fascinating technology for addressing environmental concerns and the energy crisis. Nevertheless, the quest for cost-effective, stable, and efficient photocatalysts in the realm of energy conversion remains a significant challenge. Herein, we designed novel InVO4/Ti3C2 MXene (IVTC) heterostructures by employing acid etching to produce Ti3C2 MXene with an accordion-like morphology, using the hydrothermal technique for the production of orthorhombic InVO4 nanoparticles (NPs), and integrating them through a self-assembly approach. Both field-emission scanning electron microscopy and HRTEM analyses revealed a consistent distribution of InVO4 NPs with an average size of 43.4 nm on both surfaces and between the sheets of Ti3C2 MXene. The intimate interface between the Ti3C2 MXene nanosheet and InVO4 suppressed carrier recombination and promoted charge transfer, thereby boosting photocatalytic H2 production. Under visible light exposure, the rate of hydrogen evolution is enhanced in IVTC heterostructures containing an optimized 10% loading of InVO4, exhibiting over a 3-fold increase compared to pristine InVO4 NPs, maintaining efficiency across four cycles. This research presents a promising method for designing and creating high-efficiency heterostructures possessing excellent visible-light-driven photocatalytic activity for H2 evolution.

Emerging Two-Dimensional Ti3C2-BiOCl Nanoparticles for Excellent Antimicrobial and Antioxidant Properties.

Introduction MXenes (Ti3C2) represent a group of two-dimensional inorganic compounds, produced through a top-down exfoliation method. They comprise ultra-thin layers of transition metal carbides, or carbonitrides, and exhibit hydrophilic properties on their surfaces. Utilizing Ti3C2 BiOCl nanoparticles for their antimicrobial and antioxidant attributes involves enhancing synthesis, processing, and characterization techniques. Materials and method To prepare Ti3C2 MXene, dissolve 1.6 g of LiF in 20 ml of 9M HCl. Slowly add 1 g of Ti3AlC2(titanium aluminum carbide) powder to the solution while stirring. Etch at 35°C for 24 h to remove Al layers from Ti3AlC2, leaving Ti3C2 layers. Wash the mixture with distilled water and ethanol until the pH is around 6. Collect the washed sediment by centrifugation and sonicate it in distilled water for 1 h. Centrifuge to remove unexfoliated particles. For BiOCl synthesis, dissolve 2 mmol of Bi(NO3)3·5H2O (bismuth nitrate pentahydrate) in 10 ml of 2M HCl (hydrochloric acid) with 0.5 g of PVP (polyvinylpyrrolidone). Transfer the solution to a Teflon-lined autoclave, fill it with distilled water up to 80%, and heat at 160°C for 24 h. Collect the precipitate by centrifugation, wash, and dry at 60°C for 12 h. Disperse BiOCl nanoparticles in distilled water, sonicate for 30 min, add Ti3C2 MXene dispersion, stir for 2 h, collect, wash, dry, and calcine at 400°C for 2 h. Result The Scanning Electron Microscope (SEM) utilizes electrons, rather than light, to generate highly magnified images. Energy Dispersive X-ray Spectroscopy (EDS) complements SEM by analyzing the X-ray spectrum emitted when a solid sample is bombarded with electrons, enabling localized chemical analysis. In SEM imaging, incorporating an X-ray spectrometer allows for both element mapping and point analysis. The SEM image of the prepared samples reveals accordion-like multilayer structures in BiOCl, characterized by thin sheet-like structures with numerous pores. EDS, relying on X-ray emissions from electron bombardment, facilitates detailed chemical analysis at specific locations within the sample. Conclusion Our research has shed light on the synthesis and characterization processes of two-dimensional Ti3C2 BiOCl nanoparticles, revealing their remarkable antimicrobial and antioxidant properties.

Accelerating electron transfer dynamics for efficient nitrogen photoreduction on nitrogenase-mimicking metal-organic framework/Fe-dispersed MXene

Achieving efficient artificial nitrogen fixation similar to nitrogenase under mild conditions has always been a goal pursued by human beings, but it remains a huge challenge. Herein, a novel photothermal catalyst UiO-66(Zr-Fe)/Fe-dispersed MXene having nitrogenase-mimicking electron transfer structure and electron donation mechanism is fabricated and applied in a designed gas-vapor-solid bi-phase system for efficient N2-to-NH3 conversion. The complementary role playing of UiO-66(Zr-Fe), Ti3C2 MXene and well-dispersed Fe sites are capable of simulating nitrogenase triple tandem system that in charge of electron generation, electron transfer and N2 fixation, respectively. In this well-designed catalyst, a remarkably high NH3 formation rate of 133.2 μmol g−1 h−1 under solar level illumination is recorded. This superior performance of the biomimetic structure is related to the enhanced light-to-matter interaction for effective multi-electron extraction and promoted photothermal response for accelerating surface reaction dynamics.

0D/2D CuCo2O4/Ti3C2 hybrid nanostructure as anodic nanocatalyst for direct power generation in fuel cells: Investigating annealing temperature and synergetic effect

In the present work, CuCo2O4 nanoparticles, CuCo2O4/Ti3C2, CuO/Ti3C2, and Co3O4/Ti3C2 hybrid nanostructures were synthesized. Various characterization and electrochemical methods were used to investigate the effect of annealing temperature on the catalytic properties. Based on the results, the hybrid of Ti3C2 MXene nanosheets with CuCo2O4 nanoparticles improved the active surface area and kinetics of electron transfer. The annealing temperature through affecting the crystalline structure, leads to a change in the electrocatalytic performance of nanostructures. On the other, the CuCo2O4/Ti3C2 hybrid nanostructure shows better performance than the single metal oxides (CuO and Co3O4) due to the synergistic effect of Cu and Co. Therefore, CuCo2O4/Ti3C2(200) hybrid nanostructure can be used as an efficient nanocatalyst in the electrooxidation process of alcohols in fuel cells due to its higher electrochemical surface area, higher current density (42 mA cm−2) and better stability (83.3 %) compared to other structures.

Engineering surface electronic of MXene to boost pseudocapacitive behavior

Despite exhibiting impressive capacitance performance in acidic electrolytes, MXene electrodes surfer from poor electrochemical performance in neutral electrolytes. Consequently, improving the capacitance performance of MXene electrodes within neutral electrolytes is imperative for their advancement in energy storage applications. Herein, an alloying strategy was employed to incorporate the V element into the M−site of Ti3C2 MXene. Theoretical calculations reveal that the incorporation of V atoms enhances the electronic conductivity, enlarges the work function, and improves the chemical affinity and adsorption capacity of MXene towards electrolyte ions, which are conducive to improving the capacitance performance of MXene. The as-synthesized V0.2Ti2.8C2 MXene electrode exhibits good capacitance performance and demonstrates good electrochemical stability with a specific capacitance retention as high as 86% after 10,000 charging/discharging cycles at 10 A/g. This work provides a universal strategy for developing high-performance MXene electrodes in neutral electrolyte.

Ti2TaC2: A novel out-of-plane ordered MXene towards flexible and cytocompatible supercapacitors

Exploring biocompatible and flexible supercapacitor electrode material is crucial for expanding the development of health monitoring bioelectronics. MXene films, due to their low cost, high conductivity, and excellent durability under different deformation conditions, are highly competitive in bioelectronic device applications compared with traditional carbon-based materials. Herein, a novel out-of-plane ordered double transition metal MXene (Ti2TaC2) is elaborately designed and originally synthesized, where Ti atoms preferentially reside in the outer transition metal layer and Ta atoms occupy in the middle layer. Theoretical calculations prove that the introduction of Ta species into Ti3C2 MXene enlarges the work function, raises the d-band center close to Fermi level and increases the density of states of d-orbital. Consequently, the Ti2TaC2 film delivers high specific capacitance of 313 F g−1 at 2 mV s−1 and excellent cycling stability without capacitance loss after 10,000 cycles at 10 A/g. Furthermore, the safety and cytotoxicity of Ti2TaC2 material are innovatively evaluated in vitro multiple cell lines (e.g., 293T, bEnd.3, PC-12, BV2 and HUVEC cells) and implanted into the subcutaneous tissue of mice, proving its good biosafety and cytocompatibility. The results suggest that flexible Ti2TaC2 MXene film may be a promising cytocompatible electrode material for long-term health monitoring bioelectronics.

Synergistic photocatalytic and energy performance of Ti2C MXene/ZnCo2O4 nanocomposites for environmental remediation

The growing interest in 2D MXenes and MXene-based nanomaterials stems from their unique properties, including significant interlayer spacing, adaptability, safety, surface area, and thermal conductivity. This study presents a comprehensive analysis of the synthesis, characterization, and performance evaluation of Ti2C MXene and its ZnCo2O4 nanocomposites. The Ti2C (94 %)/ZnCo2O4 (6 %) heterostructure exhibited low overpotentials of 365 mV and 474 mV for achieving ten mA/cm2 and 100 mA/cm2 current densities in the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, with Tafel slopes of 44 and 108 mV/dec. The high efficiency in splitting water and making hydrogen is due to the heterostructure's more surface-active sites, better electron transfer, and stronger electronic solid coupling. Additionally, the MXene-based nanocomposites demonstrated significant efficacy in the photodegradation of Methylene blue, with the Ti2C (94 %) and ZnCo2O4 (6 %) composite exhibiting the highest degradation rate of 80 %. This work introduces a promising design approach to mitigate the performance deterioration of 2D photocatalysts, potentially advancing the development of future high-performance photocatalysts.

Identifying the presence of subsurface oxygen on the Ti3C2 MXene using H2O as a probe molecule: A DFT study

Oxycarbide MXenes are two-dimensional transition metal carbides with subsurface oxygen content within their carbon layers. Substitutional oxygen atoms are thermodynamically very stable, impose virtually no lattice strain on their surroundings, and do not change the metallic behaviour of Ti3C2, making them very difficult to detect experimentally. Here, water is suggested as a probe to identify subsurface oxygen atoms on the H2-exposed and heat pre-treated Ti3C2 MXene. Independently of the oxygen concentration, density functional theory calculations show that water can adsorb near subsurface oxygen atoms as well as on stoichiometric Ti3C2 regions of the material and is deemed appropriate for identifying substitutional oxygen defects on Ti3C2 through frequency analysis. The calculated stretching mode of water increases by at least 67 cm−1 in the presence of subsurface oxygen, allowing the experimental detection of this defect, even at the lowest concentration considered, i.e., a replacement of 3 % of carbon by oxygen atoms.

Optimizing Light Dynamics: Designing a Ni-MOF Functionalized g-C3N4 Type II Heterostructure and a Ti3C2 MXene Schottky Junction for the Efficient Photocatalytic H2 Production.

The photocatalytic production of hydrogen (H2) from water is a vital avenue towards sustainable energy and addressing global environmental challenges. To maximize efficiency, harnessing the synergistic effects of multiple co-catalysts is essential, as these interactions can significantly enhance performance. In this study, we introduce a ternary heterojunction composed of a nickel-imidazole framework (Ni-MOF), graphitic carbon nitride (CN), and Ti3C2 MXene (TC), employing solvothermal and wet impregnation methods, featuring a well-designed Type II heterojunction and a noble metal-free Schottky junction for efficient hydrogen evolution. The Type II heterojunction between Ni-MOF and CN minimizes charge carrier recombination and promotes photogenerated electron generation, while TC as an electron acceptor enhances electron capture, increases participation in surface reactions, and augments active sites. Consequently, the Ni-MOF/CN/TC hybrid catalyst achieves outstanding photocatalytic hydrogen evolution under visible light, with a peak production rate of 1044.46 μmol/g over 3 hours, surpassing CN by 13 fold and Ni-MOF/CN by 50 %. This work provides insights into MXene-based ternary systems, emphasizing the potential for enhanced light absorption and efficient charge separation, making it a promising platform for photocatalytic applications.

Dielectric anisotropy in self-assembling MXene-based lyotropic nematic compounds

The formation of a lyotropic liquid crystal phase at the level of MXene-based aqueous dispersions due to the self-assembling capacity of these two-dimensional (2D) materials has been previously successfully reported. However, the influence of electrical external factors has been less studied in spite of the fact that understanding the electrical behaviour of 2D-based liquid crystal compounds is vital for fostering the development of new innovative applications. Consequently, within this paper, we report an in-depth evaluation of the dielectric properties of liquid crystalline phases in Ti3C2 MXene aqueous dispersions. The dependence on the low voltage of planar ε⊥′ to homeotropic ε∥′ orientational transition is emphasized and discussed, while the influence of the electric field frequency at the level of dielectric anisotropy is assessed in respect to various concentrations of MXene flakes within the same 2D-based compounds. Nonetheless, dielectric spectroscopy highlights the biphasic nature (containing both nematic and isotropic phases) of the studied aqueous Ti3C2 MXene inks visible up to 20% MXene. Above this concentration, the existence of a pure nematic phase in the dispersion of highMXene concentration (>20 wt%) was detected based on the evaluation of dielectric permittivity against various voltage values.

Lamellar Ti3C2 MXene composite decorated with platinum-doped MoS2 nanosheets as electrochemical sensing functional platform for highly sensitive analysis of organophosphorus pesticides

Precisely detecting organophosphorus pesticides (OPs) is paramount in upholding human safety and environmental preservation, especially in food safety. Herein, an electrochemical acetylcholinesterase (AChE) sensing platform entrapped in chitosan (Chit) on the glassy carbon electrodes (GCEs) decorated with Pt/MoS2/Ti3C2 MXene (Pt/MoS2/TM) was constructed for the detection of chlorpyrifos. It is worth noting that Pt/MoS2/TM possesses good biocompatibility, remarkable electrical conductivity, environmental stability and large specific surface area. Besides, the heterostructure formed by the composite of TM and MoS2 improves the conductivity and maintains the original structure, which is conducive to improving the electrochemical property. The coordination effect between the individual components enables the even distribution of functional components and enhances the electrochemical performance of the biosensor (AChE-Chit/Pt/MoS2/TM). Under optimal efficiency and sensitivity, the AChE-Chit/Pt/MoS2/TM/GCE sensing platform exerts comparable analytical performance and a wide concentration range of chlorpyrifos from 10−12 to 10−6 M as well as a low limit of detection (4.71 × 10−13 M). Furthermore, the biosensor is utilized to detect OPs concerning three kinds of fruits and vegetables with good feasibility and recoveries (94.81% to 104.0%). This work would provide a new scheme to develop high-sensitivity sensors based on the two-dimensional nanosheet/laminar hybrid structure for practical applications in environmental monitoring and agricultural product detection.

Amorphous FeSnOx Nanosheets with Hierarchical Vacancies for Room-Temperature Sodium-Sulfur Batteries.

Room-temperature sodium-sulfur (RT Na-S) batteries, noted for their low material costs and high energy density, are emerging as a promising alternative to lithium-ion batteries (LIBs) in various applications including power grids and standalone renewable energy systems. These batteries are commonly assembled with glass fiber membranes, which face significant challenges like the dissolution of polysulfides, sluggish sulfur conversion kinetics, and the growth of Na dendrites. Here, we develop an amorphous two-dimensional (2D) iron tin oxide (A-FeSnOx) nanosheet with hierarchical vacancies, including abundant oxygen vacancies (Ovs) and nano-sized perforations, that can be assembled into a multifunctional layer overlaying commercial separators for RT Na-S batteries. The Ovs offer strong adsorption and abundant catalytic sites for polysulfides, while the defect concentration is finely tuned to elucidate the polysulfides conversion mechanisms. The nano-sized perforations aid in regulating Na ions transport, resulting in uniform Na deposition. Moreover, the strategic addition of trace amounts of Ti3C2 (MXene) forms an amorphous/crystalline (A/C) interface that significantly improves the mechanical properties of the separator and suppresses dendrite growth. As a result, the task-specific layer achieves ultra-light (~0.1 mg cm-2), ultra-thin (~200 nm), and ultra-robust (modulus=4.9 GPa) characteristics. Consequently, the RT Na-S battery maintained a high capacity of 610.3 mAh g-1 and an average Coulombic efficiency of 99.9 % after 400 cycles at 0.5 C.