V2CTx MXene Research Articles

Synthesis and characterization of erbium decorated V2CTx for water splitting properties

The implication of two-dimensional (2D) MXene and their composites as catalysts for hydrogen (H2) and oxygen (O2) production represents an exciting area of research with great potential to revolutionize the field of catalysis. Herein, we demonstrated a method for surface modification of V2CTx MXene nanosheets (NSs) as an effective bifunctional nanocomposite electrocatalyst for water-splitting applications. This method involves the careful adsorption of the Erbium (Er) onto V2CTx NSs. Nanocomposites of Er@V2CTx were prepared by the sonication method. The Er@V2CTx in weight percentage ratio (0.12:1) nanocomposite (labeled as) achieved overpotentials of 174 mV vs. RHE (Reversible hydrogen electrode) and 370 mV (vs. OER) at the Tafel slope of 107 mV/dec for hydrogen evolution reaction (HER) and 131 mV/dec for the oxygen evolution reaction (OER) respectively, in 1.0 M KOH solution. The X-ray diffraction (XRD) analysis of pristine V2CTx and Er-decorated V2CTx (Er@V2CTx) nanocomposites revealed the presence of a 2D MXene structure with an increase in c-lattice parameter from 13.01 Å to 19.94 Å, indicating the successful adsorption of Er into MXene. Further, scanning electron microscopy (SEM) demonstrates that all samples have layered structures with evident sheet separation. The V2CTx MXene had strong electrical coupling, charge transfer, and contact, which resulted in substantially improved water-splitting performance, structural stability, and low charge transfer resistance, ultimately enhancing the catalyst's intrinsic activity.

Dual-modal flexible zinc-air battery-driven self-powered and impedimetric aptasensor based on the hybrid of V2CTx MXene and bimetallic layered double hydroxide for the detection of cortisol

Based on the heterojunction of V2CTx MXene and bimetallic CoNi-layered double hydroxide (CoNi-MLDH), a novel dual-modal electrochemical aptasensor (denoted as CoNi-MLDH@V2CTx) was developed for the noninvasive point-of-care detection of cortisol in different body fluids (such as sweat, urine, and blood). Herein, V2CTx nanosheets (NSs) were used as scaffolds for the in-situ growth of cobalt/nickel zeolitic imidazolate framework (CoNi-ZIF) polyhedrons, which was then converted to CoNi-MLDH NSs through an in situ etching–coprecipitating process. Benefiting from the merits of V2CTx NSs (excellent electrochemical activity) and CoNi-ZIF (large specific surface and pore size, rich functionality, excellent oxygen reduction, and strong bioaffinity toward aptamer), and from the synergistic effect, the CoNi-LDH@V2CTx junction showed great potential as a platform for the constructing the electrochemical aptasensor for detecting cortisol. Within a wide cortisol range 10 fg mL−1 to 100 ng mL−1, the dual-modal impedimetric and zinc-air battery-driven self-powered aptasensor based on CoNi-MLDH@V2CTx illustrated the ultralow detection limit of cortisol, 0.26 and 0.17 fg mL−1, respectively. They demonstrated high selectivity, superior stability, excellent reproducibility, and promising regeneration ability, and showed potential applications for cortisol analysis in different environments (sweat, urine, and blood). The present work provides a promising option for maintaining people’s mental health through the sensitive and selective detection of cortisol in human fluids.

Two-Site Enhanced Porphyrinic Metal-Organic Framework Nanozymes and Nano-/Bioenzyme Confined Catalysis for Colorimetric/Chemiluminescent Dual-Mode Visual Biosensing.

The rational design of efficient nanozymes and the immobilization of enzymes are of great significance for the construction of high-performance biosensors based on nano-/bioenzyme catalytic systems. Herein, a novel V-TCPP(Fe) metal-organic framework nanozyme with a two-dimensional nanosheet morphology is rationally designed by using V2CTx MXene as a metal source and iron tetrakis(4-carboxyphenyl)porphine (FeTCPP) ligand as an organic linker. It exhibits enhanced peroxidase- and catalase-like activities and luminol-H2O2 chemiluminescent (CL) behavior. Based on the experimental and theoretical results, these excellent enzyme-like activities are derived from the two-site synergistic effect between V nodes and FeTCPP ligands in V-TCPP(Fe). Furthermore, a confined catalytic system is developed by zeolitic imidazole framework (ZIF) coencapsulation of the V-TCPP(Fe) nanozyme and bioenzyme. Using the acetylcholinesterase (AChE) as a model, our constructed V-TCPP(Fe)/AChE@ZIF confined catalytic system was successfully used for the colorimetric/CL dual-mode visual biosensing of organophosphorus pesticides. This work is expected to provide new insights into the design of efficient nanozymes and confined catalytic systems, encouraging applications in catalysis and biosensing.

Advanced design of bimetal sulfide/V2CTX MXene photothermal nanocomposites for integrated solar steam generation, electricity generation, and water purification

The utilization and conversion of solar energy is considered an environmentally friendly strategy to achieve global carbon peak and carbon neutrality. To synergistically alleviate freshwater and electricity scarcity, designing multifunctional photothermal composites that are highly efficient and stable is particularly important. Herein, a multifunctional Cu3BiS3@V2C/BF membrane with a bilayer structure has been developed, the top is Cu3BiS3@V2C-1 nanocomposite coating, and the bottom is porous BF membrane, the interface matching is achieved by coordination effect of calcium ions and carboxylate group. The Cu3BiS3@V2C-1/BF membrane can achieve a broadband absorption of ≈95.2 % in the full spectrum, benefitting from the near-infrared spectral compensation mechanism. Further, a high evaporation rate of 1.68 kg m−2 h−1 is achieved by the synergetic design of multistage photothermal conversion and the decrease in evaporation enthalpy. Moreover, the membrane has high solar desalination efficiency, electricity generation of 55 mV under one sun, and water purification performance, which profit from the unique sodiophilic property of V2CTx MXene, the enhanced photothermal catalysis and the abundant adsorption sites of Cu3BiS3@V2C-1 nanocomposite. Furthermore, the deep mechanism of photothermal conversion and photothermal catalytic is analyzed using first-principles calculation. This work is a promising approach to focus on multifunctional solar utilization in the future.

Lubrication mechanism of polyimide/V2CTx MXene composites based on surface chemistry

AbstractA series of polyimide (PI)/V2CTx MXene composites was synthesized via polyamide acids (PAA) and two‐dimensional (2D) V2CTx MXene obtained by etching precursor V2AlC. PI/V2CTx MXene composites with different mass ratios were obtained by blending and heating with PAA. The results showed that V2CTx MXene has excellent dispersion in PI. In particular, V2CTx MXene exhibited excellent friction reduction and anti‐wear properties as a solid lubricant additive, and the wear rate (WR) was reduced by 43.2% by incorporating only 0.8 wt% of V2CTx MXene in the pristine PI and 71.9% by incorporating 1.2 wt%. Scanning electron microscopy (SEM) and x‐ray photoelectron spectroscopy (XPS) analyses showed that the continuous transfer film consisting of a high proportion of tribo‐chemical products formed on the contact surface is significant to improve the lubrication performances of the PI composites. This work broadens the application of MXene in the field of tribology and contributes to energy conservation and sustainable development of human society.Highlights The tribological properties could be tuned by changing the ratio of PI to V2CTx MXene. The WR of PI composites was reduced by 71.9% with incorporating 1.2 wt% of V2CTx MXene. The formation of transfer films on the contact surface is significant for improving anti‐wear of PI.

Defective porphyrin-based metal-organic framework nanosheets derived from V2CTx MXene as a robust bioplatform for impedimetric aptasensing 17β-estradiol

An electrochemical aptasensor was prepared for the efficient, sensitive, and selective detection of 17β-estradiol. The sensor was based on a defective two-dimensional porphyrin-based metal-organic framework derived from V2CTx MXene. The resulting metal-organic framework nanosheets benefited from the advantages of V2CTx MXene nanosheets and porphyrin-based metal-organic framework, two-dimensional porphyrin-based metal-organic framework nanosheets demonstrated amplified electrochemical response and enhanced aptamer-immobilization ability compared with V2CTx MXene nanosheets. The sensor's detection limit was ultralow at 0.81fgmL-1 (2.97 fM), and the 17β-estradiol concentration range was wide, thereby outperforming most reported aptasensors. The high selectivity, superior stability and reproducibility, and excellent regeneration performance of the constructed aptasensor indicated its remarkable potential application for 17β-estradiol determination in diverse real samples. This aptasensing strategy can be used to analyze other targets by replacing the corresponding aptamer.

Metal ion assistant transformation strategy to synthesize catechol-based metal–organic frameworks from Ti3C2Tx precursors

Chemical transformation strategy is capable of fabricating nanomaterials with well-defined structures and fascinating performance via controllable crystallization kinetics in the phase transformation. V2CTx MXene has been used as precursors to fabricate vanadium porphyrin metal–organic frameworks (V-PMOFs) via the coordination of deprotonated carboxylic acid ligands. However, the rational and in-depth exploration of synthesis mechanism with the aim of enriching the variety of MXene (i.e., Ti3C2Tx) and organic ligands (i.e., catechol-based) to design new MOFs is rarely reported. Herein, we have first developed a metal ion assistant transformation strategy to synthesize three-dimensional catechol-based TiCu-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) MOFs with a non-interpenetrating SrSi2 (srs) framework using two-dimensional Ti3C2Tx as precursors. The unique synergetic transformation mechanism involves the electron transfer from Ti3C2Tx to electrostatically adsorbed Cu2+ ion for redox reaction, the subsequent Ti–C bond rupture for Ti4+ ion release, and the continuous chelation coordination between Ti4+/Cu2+ and HHTP. Ti3C2Tx precursors and auxiliary metal ion could be rationally substituted by V2CTx and Mn+ (e.g., Ni2+, Co2+, Mn2+, and Zn2+), respectively. This strategy lays the foundation for the design and synthesis of innovative and multifarious MOFs derived from MXene or other unconventional metal precursors.

2D MXenes polar catalysts for multi-renewable energy harvesting applications

The synchronous harvesting and conversion of multiple renewable energy sources for chemical fuel production and environmental remediation in a single system is a holy grail in sustainable energy technologies. However, it is challenging to develop advanced energy harvesters that satisfy different working mechanisms. Here, we theoretically and experimentally disclose the use of MXene materials as versatile catalysts for multi-energy utilization. Ti3C2TX MXene shows remarkable catalytic performance for organic pollutant decomposition and H2 production. It outperforms most reported catalysts under the stimulation of light, thermal, and mechanical energy. Moreover, the synergistic effects of piezo-thermal and piezo-photothermal catalysis further improve the performance when using Ti3C2TX. A mechanistic study reveals that hydroxyl and superoxide radicals are produced on the Ti3C2TX under diverse energy stimulation. Furthermore, similar multi-functionality is realized in Ti2CTX, V2CTX, and Nb2CTX MXene materials. This work is anticipated to open a new avenue for multisource renewable energy harvesting using MXene materials.

Tailoring composites via in situ growth of Co-MOF on V2CTx MXene as high-performance anode for lithium-ion batteries

MXenes, as a new family of 2D materials, have attracted extensive attention for their high electrical conductivity and good electrochemical cycling stability. However, due to the self-stacking nature of MXene materials, the actual specific capacity (260 mAh g−1) of V2CTx MXene materials as anodes is much lower than the theoretical specific capacity (940 mAh g−1). Herein, we designed a novel Co-MOF/V2CTx composite (denoted as Co-MOF/V2CTx), where Co-MOF was in situ grown on the surface and interlayer of the V2CTx MXene with larger interlayer spacing. The MOF in the composite provides the additional specific capacity as well as effectively prevented the restacking of V2CTx MXene, which exposed more Li+ active sites. Besides, benefiting from the high conductivity, electrochemical stability, and strong bonding with the Co-MOF at the interface of MXene, the structural stability of Co-MOF itself in composite materials can be better improved. Consequently, the cells with Co-MOF/V2CTx anodes realize a high specific capacity of 484.3 mAh g−1 after 120 cycles at 100 mA g−1 and superior cycling stability even at a higher current density of 500 mA g−1. The unique synergistic design of this work can provide new ideas for the development of MXene-based composites in energy storage applications.

Anchoring metal-organic framework-derived hollow CoV2O6 nanocubes onto lattice tensile strained V2CTx MXene for superior overall water splitting

MXene is considered as a kind of promising two-dimensional layered carbide/nitride in the field of overall water splitting attributed to hydrophilic surface, controllable interlayer spacing, and desirable metal conductivity. Nevertheless, the re-stack effect still hinders its large-scale development. Therefore, in this work, metal-organic frameworks-derived hollow CoV2O6 nanocubes anchored on the surface of lattice tensile strained V2CTx MXene (TS-V2CTx/CoV2O6 HN) as electrocatalysts are prepared through ion exchange process and the following liquid nitrogen quenching treatment. Lattice tensile strain could boost ions transfer of transition metals due to the enlarger interlayer spacing. The heterostructure between CoV2O6 and V2CTx MXene could optimize the adsorption energy of H- and O-containing intermediates to obtain the best ΔGH* for hydrogen evolution reaction (HER) and decrease the ΔG value of rate determining step for oxygen evolution reaction (OER). Besides, the CoV2O6 components acting as intercalation agents could avoid the self-aggregation of MXene nanosheets. Simultaneously, the hollow structure also offers high active area to promote electrolyte permeation and accelerate electron/ion transfer. As a consequence, the TS-V2CTx/CoV2O6 HN acquires extraordinary HER and OER performance with the overpotential of 32.2 and 235.0 mV at the current density of − 10 mA/cm2 and 10 mA/cm2, respectively, which is quite remarkable compared to the recent MXene-based electrocatalysts. Moreover, the overall water splitting device assembled by TS-V2CTx/CoV2O6 HN demonstrates a low cell voltage of 1.358 V at 10 mA/cm2. Thence, this work donates an exciting avenue to overcome the re-stack issue of V2CTx MXene, constructing a superior electrocatalyst with high activity and desirable reaction kinetics.

Cooperative energy storage behaviors derived from PANI and V2CTx MXene for advanced aqueous zinc-ion batteries

Polyaniline (PANI) were anchored to the surface of O-V2CTx MXene to arrange a three-dimensional architecture of hybrid composites via an electrostatic self-assembly process. The accessible surface of O-V2CTx MXene derived from the emergence of vanadium-oxygen terminations in the opening aqueous suspension contributes to attracting positively charged PANI, followed by the transformation of C-V/V2+ to V3+ and V4+ species on the surface of O-V2CTx MXene through an in situ oxidation process. The intercalation of PANI as spacing blocks into the interlayer region between O-V2CTx nanosheets is capable to suppress the re-stacking of O-V2CTx MXene in favor of accelerating Zn2+ diffusion processes and enrich surface electrochemical active sites of O-V2CTx MXene in dependence on cooperative charge storage processes between heterogeneous constituents. The result shows that PANI/O-V2CTx composites achieve a reversible capacity of 267.7 mAh g−1 at 0.2 A g−1 in comparison with those of 135.1 mAh g−1 for PANI and 116.2 mAh g−1 for O-V2CTx MXene. After 2000 cycles, PANI/O-V2CTx composites also exhibit the excellent cycling stability with a high capacity retention of 91.8% at 5 A g−1. Moreover, ex situ structural characterizations reveal the realization of the reversible redox transformation between V4+ and V5+ species on the surface vanadium-oxygen coating of O-V2CTx MXene with the aid of electrochemical active PANI.

Tuning coordination microenvironment of V2CTx MXene for anchoring single-atom toward efficient multifunctional electrocatalysis

The rational design of low-cost and high-performance multifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution/reduction reaction (OER/ORR) is essential for efficient overall water splitting and rechargeable metal-air battery. Herein, through density functional theory calculations, we creatively regulate the coordination microenvironment of V2CTx MXene (M−v−V2CT2, T = O, Cl, F and S) as substrates of single-atom catalysts (SACs), and then systematically explore their HER, OER, and ORR electrocatalytic performance. Our results disclose that Rh-v-V2CO2 is a promising bifunctional catalyst for water splitting (overpotentials of 0.19 and 0.37 V for HER and OER). Besides, Pt-v-V2CCl2 and Pt-v-V2CS2 possess desirable bifunctional OER/ORR activity with overpotentials of 0.49/0.55 V and 0.58/0.40 V, respectively. More interestingly, Pt-v-V2CO2 is a promising trifunctional catalyst under vacuum, implicit and explicit solvation conditions, which transcends commercially used Pt and IrO2 catalysts for HER/ORR and OER. The electronic structure analysis further demonstrates that surface functionalization can optimize the local microenvironment of the SACs and thus tune the interaction strength of intermediate adsorbates. This work provides a feasible strategy for developing advanced multifunctional electrocatalysts and enriches the application of MXene in energy conversion and storage.

Direct writing additive-free V2CTx MXene architectures enables Zn-ion hybrid capacitor with ultrahigh energy density

Constructing a Zinc ion hybrid supercapacitor (ZHMSC) configuration with excellent electrochemical performance for progressive energy storage is worldwide attractive but yet still a considerable challenge. In this study, a universal and effective strategy has been proposed and developed for 3D-writing additive-free V2CTx MXene architected ZHMSC to realize the excellent electrochemical performance. With proper designs of printable electrochemical materials and direct ink writing architectures, 3D printed ZHMSC devices with high areal capacitance and excellent areal energy density have been achieved in a limited footprint area. Benefitting from the excellent ion diffusion and highly conductive networks, the 3D printed ZHMSCs device achieves the ultrahigh specific capacitance of 3.82 F cm−2, large energy density of 1.36 mW h cm−2 and remarkable cyclic performance with the capacitance retention of 97.8 % after 12,000 cycles at 20 mA cm−2. This work not only provides new insights on direct ink writing for high-performance Zn-Ion hybrid capacitor, but also offers a facile and efficient method to construct large-scale energy storage devices with high electrochemical performance for future energy storage.

Effect of temperature and atmosphere on V2AlC etching for V2CTx MXenes synthesis used as anode for Li-ion storage systems

This study investigated the effect of the Ar-controlled atmosphere on the etching of the V2AlC MAX phase and the electrochemical properties for Li-ion storage. First, the V2AlC MAX phase was etched at room temperature for 92 h by 48 % HF acid in an ambient atmosphere. The results showed incomplete etching, and HF's penetration paths into the MAX phase were closed due to oxidation. Second, the etching process was conducted in an Ar- controlled atmosphere. The process was done in different temperatures, 9, 25, and 40 °C. The EDS results showed that an increase in temperature is necessary for completing the etch reaction. Also, controlling the temperature (9 °C) during the MAX phase addition to the acid prevents an oxide layer on the MAX phase surface. Therefore, the paths for the penetration of the acid into the V2AlC MAX phase will remain open, and the etching process by increasing the temperature up to 40 °C will be more progressed. The discharge capacity of Li-ion storage for the V2CTx, which was etched at 9 + 40 °C in an Ar-controlled atmosphere for 92 h by 48 % HF acid, was 500.5 mAh g−1 at 50mA g−1 for the first cycle and 388.5 mAh g−1 at 100mA g−1 after 100cycles with 99.4 % coulombic efficiency.

A self-powered ultraviolet photodetector with van der Waals Schottky junction based on TiO2 nanorod arrays/Au-modulated V2CTx MXene

A self-powered ultraviolet photodetector (UV PD) with van der Waals (vdW) Schottky junction based on TiO2 nanorod arrays/Au-modulated V2CTx MXene is reported. The Schottky junction enables the device to operate in self-powered mode. The dangling bond-free surface of V2CTx MXene reduces the charge recombination at the junction interface. Meanwhile, V2CTx MXene, with the work function (WF) increasing to 5.35 eV, forms a hole transport layer by contacting with Au electrode, which facilitates the carrier extraction. The electron lifetime in the device has prolonged to 8.95 μs. As a result, the responsivity and detectivity of the PD have achieved 28 mA/W and 1.2 × 1011 cm Hz1/2/W (340 nm, 65 mW/cm2, 0 V), respectively. In addition, the presence of the Au electrode prevents the vanadium from coming into contact with oxygen and oxidizing, preserving the properties of the V2CTx films. After 180 days of exposure to the atmosphere, the device performance remained at a particularly high level, indicating enhanced durability. This work points out an effective approach to modulate the properties of V2CTx to obtain the high performance and stability of the UV PD.

Facile Tailoring of Surface Terminations of MXenes by Doping Nb Element: Toward Extraordinary Pseudocapacitance Performance.

MXenes show promising potential in supercapacitors due to their unique two-dimensional (2D) structure and abundant surface functional groups. However, most studies about MXenes have focused on tailoring surface structures by alternating synthesis methods or post-etch treatments, and little is known about the inherent relationship between surface groups and M elements. Herein, we propose a simple and novel strategy to adjust the surface structure of few-layered MXene flakes by adding a small amount of Nb element. Because of the strong affinity between Nb and O elements, the as-received V1.8Nb0.2CTx and Ti2.7Nb0.3C2Tx MXenes have much fewer -F functional groups and a higher O content than V2CTx and Ti3C2Tx MXenes, respectively. Thus, both V1.8Nb0.2CTx and Ti2.7Nb0.3C2Tx MXenes show enhanced pseudocapacitance performance. Especially, V1.8Nb0.2CTx delivers an ultrahigh volumetric capacitance of 1698 F/cm3 at a scan rate of 2 mV/s. Moreover, benefiting from the high activity of MAX precursors obtained through a fast self-propagating high-temperature synthesis, the etching time to produce V-based MXenes is much shorter than that in previous reports. Therefore, the results presented here are applicable to the surface engineering and rational design of 2D MXene materials and develop them into promising, cost-effective electrode materials for supercapacitors or other energy-storage equipment.

Post-Ammonia-Treated V2CTx MXene at Different Pressures: Effects on Morphology, Electronic, and Optical Properties

In the present work, vanadium carbide (V2CTx) MXene was synthesized successfully and then treated with an ammonia solution (NH4OH) under different pressures using a hydrothermal process. The sample morphology reveals that the V2CTx MXene gradually changed from uneven multilayered micrometre-size sheets to uniform few-layered nanometer-size sheets as the pressure increased. The optical emission spectra show broad emission and a blue shift due to nitrogen-related defects and quantum confinement. X-ray photoelectron spectroscopy shows the presence of nitrogen in all of the samples. The ultraviolet photoelectron spectroscopy study shows a modified density of states near the Fermi level and a maximum of ∼0.6 eV valence band edge shift towards a higher binding energy side after post-treatment with ammonia. More interestingly, the E1g Raman band becomes degenerate and the E1g band upshifts (∼15 cm–1) with increasing pressure treatment. The Raman results suggest that the induced lattice strain due to post-ammonia treatment plays a crucial role in deciding the optical and electronic properties.

V2CTX MXene-based hybrid sensor with high selectivity and ppb-level detection for acetone at room temperature

High-performance, room temperature-based novel sensing materials are one of the frontier research topics in the gas sensing field, and MXenes, a family of emerging 2D layered materials, has gained widespread attention due to their distinctive properties. In this work, we propose a chemiresistive gas sensor made from V2CTx MXene-derived, urchin-like V2O5 hybrid materials (V2C/V2O5 MXene) for gas sensing applications at room temperature. The as-prepared sensor exhibited high performance when used as the sensing material for acetone detection at room temperature. Furthermore, the V2C/V2O5 MXene-based sensor exhibited a higher response (S% = 11.9%) toward 15 ppm acetone than pristine multilayer V2CTx MXenes (S% = 4.6%). Additionally, the composite sensor demonstrated a low detection level at ppb levels (250 ppb) at room temperature, as well as high selectivity among different interfering gases, fast response-recovery time, good repeatability with minimal amplitude fluctuation, and excellent long-term stability. These improved sensing properties can be attributed to the possible formation of H-bonds in multilayer V2C MXenes, the synergistic effect of the newly formed composite of urchin-like V2C/V2O5 MXene sensor, and high charge carrier transport at the interface of V2O5 and V2C MXene.

Chemoresistive Properties of V2CTx MXene and the V2CTx/V3O7 Nanocomposite Based on It

The in-situ Raman spectroscopy oxidation of the accordion-like V2CTx MXene has been studied. It was found that a nanocomposite of V2CTx/V3O7 composition was formed as a result. The elemental and phase composition, the microstructure of the synthesized V2CTx powder and MXene film as well as the V2CTx/V3O7 nanocomposite obtained at a minimum oxidation temperature of 250 °C were studied using a variety of physical and chemical analysis methods. It was found that the obtained V2CTx and V2CTx/V3O7 films have an increased sensitivity to ammonia and nitrogen dioxide, respectively, at room temperature and zero humidity. It was shown that the V2CTx/V3O7 composite material is characterized by an increase in the response value for a number of analytes (including humidity) by more than one order of magnitude, as well as a change in their detection mechanisms compared to the individual V2CTx MXene.

V2CTx MXene Nanosheets as Enhanced Free-Radical Scavengers for Alleviating Oxidative Stress

The development of antioxidants with high efficiency and biocompatibility is highly desired to prevent and treat free radical-related diseases. MXene, a two-dimensional (2D) ultrathin nanosheet, is a promising antioxidant material. Herein, we report a V2CTx MXene antioxidant that shows a significant scavenging effect on a variety of free radicals (DPPH·, ·OH, ·O2–, and 1O2.). The scavenging efficiency for DPPH· is ∼100% in 10 min, and the EC50 value is calculated to be 6.7 μg/mL, superior to that of most 2D and zero-dimensional materials reported so far. Furthermore, a combination of H-donation and the electron transfer mechanism was proposed based on the analysis of the free radical scavenging behavior of V2CTx and the reaction process. We hope that this study will provide new ideas for the treatment and prevention of ROS-mediated inflammatory and neurodegenerative diseases.