Search Results (359)

Two-dimensional carbide crystals (MXenes) are emerging as a promising platform for the development of novel gas sensors, offering advantages in energy efficiency and tunable analyte selectivity. One of the most effective strategies to enhance and tailor their functional performance involves forming hetero-structured composites with metal oxides. In this work, we explore a chemiresistive effect in double-metal MXene of Ti_0.2V_1.8C and its composites with 2 mol. % SnO₂ and Co₃O₄ nanocrystalline oxides toward feasibility tests with alcohol and ammonia vapor probes. The materials were characterized by simultaneous thermal analysis, X-ray diffraction analysis, Raman spectroscopy, and scanning/transmission electron microscopy. Gas-sensing experiments were carried out on composite layers deposited on multi-electrode substrates to be exposed to the test gases, 200–2000 ppm concentrations, at an operating temperature of 370 °C. The developed sensor array demonstrated clear analyte discrimination. The distinct sensor responses enabled a selective identification of vapors through linear discriminant analysis, demonstrating the further potential of MXene-based materials for integrated electronic nose applications. Full article

The intrinsic limitations of Ti₃C₂T_x electrodes, specifically low interfacial charge-transfer efficiency and structural degradation in strongly acidic environments, hinder their performance in high-rate aqueous supercapacitors. Herein, we report a synergistic strategy combining nitrogen plasma surface engineering with a redox-active ascorbic acid electrolyte to optimize the electrode/electrolyte interfacial kinetics. By systematic investigation, the Ti₃C₂T_x supercapacitor obtained by a 10-min plasma duration (N10P-AA) achieved the optimal balance between activating surface sites and preserving the conductive Ti–C framework integrity. The ascorbic acid electrolyte broadened the potential window to approximately 0.7 V, and N10P-AA exhibited the lowest charge-transfer impedance and superior rate capability, retaining a relatively high Coulombic efficiency (>72%) even at a high scan rate of 10,000 mV·s⁻¹. The EIS results and kinetics analysis (b values) confirmed that the moderate plasma activation effectively promoted more surface-dominated charge storage kinetics and mitigated diffusion limitation, consistent with reduced charge-transfer resistance and a smaller Warburg slope. The XPS results revealed that the 10-min treatment suppressed detrimental oxidation during cyclings and facilitated the formation of electrochemically favorable hydroxylated surface functional groups. This work demonstrates a feasible surface electrolyte co-engineering strategy for modulating the interfacial behavior of MXene, which is of great significance for future high-efficiency aqueous electrochemical energy storage and potential biosensing applications. Full article

The reliable integration of high-performance noble metal interfaces with flexible substrates is a key requirement for wearable electronics. However, achieving uniform, mechanically robust and functionally active coatings on fabric surfaces remains highly challenging. This study reports the atomic-layered-deposition (ALD) growth of platinum (Pt) on textile at low temperatures. Through ozone plasma-assisted activation technology, Pt nucleation can be achieved at 100 °C, forming a dense and defect-suppressed Pt layer that substantially increases the surface oxygen functional groups and enhances binding affinity. The resulting Pt layer also significantly enhances the adsorption behavior and sensing performance of Ti₃C₂T_x MXene gel inks on textile. At the atomic scale, the engineered Pt–MXene interface promotes stronger adsorption of MXene sheets and establishes efficient electron/ion transport pathways within the gel network. Ultimately, the conductive textile treated with Pt functionalized layers (MXene/Pt@textile) exhibits significantly enhanced sensing sensitivity and signal stability, enabling precise detection of human motions, pressure, and subtle physiological vibrations. The synergistic effect of ALD Pt layers and MXene gel inks creates a textile platform combining robustness, breathability, and high responsiveness. Full article

With the rapid advancements in industrial technology, the demand for high-performance lubrication has surpassed the capabilities of traditional solid or liquid lubricants. In this study, a novel MXene-based solvent-free lubricating nanofluid was developed through the surface functionalization of Ti₃C₂T_x MXene nanosheets. This innovative material combines the superior mechanical properties of solid Ti₃C₂T_x MXene nanosheets with the stable flow and rapid self-repairing capabilities of liquid lubricants. The successful synthesis of the MXene-based solvent-free nanofluid lubricant was confirmed through a series of characterization techniques, and it was demonstrated that this nanofluid maintained excellent flowability at room temperature. Subsequent tribological tests revealed that the friction coefficient and the wear performance of the MXene-based solvent-free nanofluid lubricant improved with increasing mass concentrations of Ti₃C₂T_x MXene nanosheets under consistently applied loads. These results indicate that the MXene-based solvent-free nanofluid lubricant significantly reduces friction and wear, showcasing its potential as a high-performance lubricant for industrial applications. Full article

Tea polyphenols (TP) offer health benefits, but their stability is compromised by sensitivity to environmental factors, limiting their applications. Developing stimulus-responsive delivery systems that precisely control TP release is essential. This study prepared novel hydrogel beads encompassing carboxymethyl chitosan (CMC), sodium alginate (SA), and MXene (Ti₃C₂T_x) using a blending method for the sustained release of TP. After being exposed to 808 nm near-infrared (NIR) radiation, the beads demonstrated excellent stability in simulated gastric conditions, resulting from the pH-dependent solubilization, facilitating controlled TP release under simulated intestinal conditions. The drug release kinetics conformed to the Ritger–Peppas model. Notably, CMC-SA-MXene@TP exhibited strong antioxidant activity and antimicrobial properties, effectively inhibiting the growth of S. aureus (ATCC 6538) and E. coli (ATCC 25922). Additionally, according to in vitro cellular assays, they exhibited good biocompatibility with normal liver cells (HL-7702) and could effectively inhibit hepatocellular carcinoma cells (HepG2). These hydrogel beads, featuring excellent pH and NIR responsiveness, biocompatibility, drug loading efficiency, antioxidant capability, and antibacterial activity, represent promising candidates for advanced wound dressings or oral drug delivery systems for modulating intestinal flora. Full article

Aluminum hydride (AlH₃) features a theoretical hydrogen content of 10.1 wt%, with initial hydrogen desorption temperatures generally ranging from 150 to 200 °C. However, its metastability makes it complicated to achieve low hydrogen desorption temperatures alongside high desorption capacities, which has limited its practical application. This study aims to improve the hydrogen desorption performance of AlH₃ by incorporating different MXenes (V₂C, Nb₂C, Ti₃C₂, Ti₃CN) accompanied by ball milling condition and catalyst content optimizations. It was shown that AlH₃ catalyzed with 1 wt% Nb₂C, ball milled at 300 rpm for 180 min under an argon atmosphere, exhibits the best performance, achieving an initial hydrogen desorption temperature of 95 °C and a final hydrogen desorption content of 9.3 wt%. It was further demonstrated that Nb₂C MXene mainly acts as an efficient catalyst for the hydrogen desorption process of AlH₃ and can extend the Al–H bonds of AlH₃ in local interphase regions observed by means of theoretical calculation, thus enhancing the hydrogen desorption performance of AlH₃. This work proposes a method to achieve high-capacity and low-temperature hydrogen desorption from metastable AlH₃ through proper ball milling and the introduction of MXenes. Full article

In this study, SiHfCN ceramics were synthesized from a single-source precursor obtained by reacting Durazane 1800 with tetrakis(dimethylamido)hafnium(IV) (TDMAH). In a separate preparation, Ti₃C₂ MXene was incorporated into this precursor to produce MXene-SiHfCN composite ceramics. The samples were pyrolyzed at 1000 °C and heat-treated at 1600 °C in N₂ to investigate amorphous-to-crystalline transformations. Both SiHfCN and MXene-SiHfCN formed a single-phase amorphous structure after pyrolysis at 1000 °C. At 1600 °C, SiHfCN partially crystallized into α/β-Si₃N₄ and HfC_xN_1−x phases within an amorphous/crystalline Si₃N₄ matrix. In contrast, the MXene–SiHfCN matrix remained largely amorphous, evolving into SiOCN with localized Si₂ON₂ crystallization. Additional phases, including HfC_xN_1−x, Hf oxide/oxycarbide, and a Ti carbonitride-rich phase (TiC_0.63N_1.06O_0.18Si_0.99Hf_0.11), were identified within the amorphous SiOCN. No SiC was detected in either system, indicating suppression of carbothermal reduction of Si₃N₄ up to 1600 °C in N₂. While SiHfCN exhibited pronounced macroscopic cracks, MXene-SiHfCN showed no such large cracks, though local microscopic cracking was observed. These results demonstrate that Ti₃C₂ MXene incorporation stabilizes the amorphous matrix, modifies phase evolution, and mitigates severe cracking, offering new insights into non-oxide PDC nanocomposites for ultra-high-temperature applications. Full article

To address the bottleneck of insufficient broadband sound insulation performance of traditional sound insulation materials at the subwavelength scale, this paper designs a composite subwavelength sound insulation unit (size: 20 mm × 20 mm × 5 mm) composed of Ti₃C₂T_x MXene, and PZT-5H piezoelectric ceramics, and porous aluminum alloy. Based on the electromagnetic-structural-acoustic multi-physics field coupling theory, the regulation laws of external electric field intensity and effect of MXene layer number on sound insulation performance are systematically investigated via numerical simulation, and the sound insulation enhancement mechanism dominated by dielectric tunability is clarified. The results show that the dielectric constant of MXene increases monotonically with the external electric field intensity, and the optimal regulation sensitivity is achieved when the layer number N = 3; when the electric field intensity increases from 0 V to 500 V, the equivalent density of the system increases from 1.25 g/cm³ to 1.87 g/cm³, the acoustic impedance increases from 3.42 × 10⁶ Pa·s/m³ to 5.13 × 10⁶ Pa·s/m³, the average transmission loss TL in the 200–600 Hz frequency band is increased by 2 dB compared with the state without electric field, and the sound pressure on the transmission side is reduced by 3.56% at 400 Hz; the vibration displacement of PZT decreases from 0.0055 mm to nearly 0 mm with the increase in electric field, and the electric field energy density increases from 0 J/m³ to 7.47056 × 10³ J/m³, verifying the core mechanism of converting electromagnetic energy into structural damping through dielectric loss. This study supplements parameter sensitivity analysis and literature benchmark comparison to compensate for the lack of experimental data, confirming the stability and rationality of the simulation results. The established cross-field coupling framework of “dielectric regulation–density optimization–impedance matching–sound insulation enhancement” fills the theoretical gap of the coupling mechanism of MXene in the field of subwavelength sound insulation, and provides new theoretical and technical pathways for the design of broadband active sound insulation materials in the 200–1000 Hz frequency range. Full article

The global decarbonisation strategy has accelerated the shift toward renewable energy and electric transport, demanding advanced electrochemical energy storage systems. Conventional anodes such as graphite and silicon composites face challenges in conductivity, stability and cycling performance. MXenes, a class of two-dimensional (2D) materials, offer promising alternatives owing to their metallic conductivity, tunable surface chemistry and high theoretical capacity. Here, we synthesise and characterise Mo₂TiC₂T_x and V₂CT_x (T = O, OH, F and/or Cl) MXenes for lithium-ion battery anodes and supercapacitors. Unlike Ti₃C₂T_x, which stores charge via intercalation and surface redox reactions, Mo₂TiC₂T_x and V₂CT_x exhibit conversion-type mechanisms. We also identify novel V₂C–VO_x heterostructures, achieving a specific capacitance of 532.4 F g⁻¹ at 2 mV s⁻¹ and an initial capacity of 493.3 mAh g⁻¹ at 50 mA g⁻¹ in lithium half-cells, with a low decay rate of 0.071% per cycle over 200 cycles. Pristine Mo₂TiC₂T_x shows 391.7 mAh g⁻¹ at 50 mA g⁻¹, decaying by 0.109% per cycle. These results experimentally validate theoretical predictions, revealing how MXene structure and transition metal chemistry govern electrochemical behaviour, thus guiding electrode design for next-generation batteries and supercapacitors. Full article

Lithium–sulfur (Li-S) batteries are renowned for their high theoretical energy density and low cost, yet their practical implementation is hampered by the polysulfide shuttle effect and sluggish redox kinetics. Herein, a sol–gel strategy is proposed to engineer a multifunctional MXene/Fe₃O₄ composite as an efficient mediator for the cathode interlayer. The synthesized composite features Fe₃O₄ nanospheres uniformly anchored on the highly conductive Ti₃C₂T_x MXene lamellae, forming a unique 0D/2D conductive network. This structure not only provides abundant polar sites for strong chemical adsorption of polysulfides but also significantly enhances charge transfer, thereby accelerating the conversion kinetics. As a result, the Li-S battery based on the MXene/Fe₃O₄ interlayer delivers a high initial discharge capacity of 1367.1 mAh g⁻¹ at 0.2 C and maintains a stable capacity of 1103.4 mAh g⁻¹ after 100 cycles, demonstrating an exceptionally low capacity decay rate of only 0.19% per cycle. Even at a high rate of 1 C, a remarkable capacity of 1066.1 mAh g⁻¹ is retained. Electrochemical analyses confirm the dual role of the composite in effectively suppressing the shuttle effect and catalyzing the polysulfide conversion. This sol–gel engineering approach offers valuable insight into the design of high-performance mediators for advanced Li-S batteries. Full article

We report an interracially engineered Co₃O₄@Ti₃C₂T_x MXene hybrid as a high-rate charge-storage electrode. Low-temperature assembly under inert conditions preserves the MXene carbide while anchoring nanocrystalline Co₃O₄ on conductive, ion-permeable sheets. XRD and FTIR confirm the structural integrity of MXene without TiO₂ formation. Electrochemically, cyclic voltammetry, Dunn analysis, and galvanostatic tests reveal mixed storage with a dominant pseudocapacitive contribution, while EIS fitting shows reduced charge-transfer resistance for the hybrid compared with either parent. Within a 0.6 V window in 2 M KOH, the composite delivers high specific charge and excellent rate retention, attributable to shortened diffusion paths and fast electron transport at the oxide–MXene interface. These results establish Co₃O₄@MXene as a robust, mechanism-consistent platform for high-power supercapacitors. Full article

Transition metal carbides/nitrides (MXenes) nanosheets have emerged as promising candidates for constructing high-performance nanofiltration (NF) membranes for separation processes. However, MXene membranes exhibit limited feasibility due to the instability of their microstructure, which can lead to failure in the filtration process. This study presents a bridging strategy (polyethyleneimine and polydopamine) to prepare a stable titanium carbide (Ti₃C₂) membrane, resulting in superior nanofiltration efficiency. Polyethyleneimine intercalation can inhibit the tendency to swell, while polydopamine enhances the force between the substrate and nanosheets. The optimized membrane possesses a permeate flux of 112.3 L m⁻² h⁻¹ bar⁻¹ (1.6 times higher than pristine Ti₃C₂ membrane) and good selectivity (methyl blue rejection rate: ~99.5%; Na₂SO₄ rejection rate: <5.0%). In addition, the prepared membrane has good long-time durability and is more suitable for low pressure nanofiltration. Notably, the bridging strategy is also applicable to various two-dimensional lamellar membranes. This strategy provides a universal method for enhancing the stability of two-dimensional membranes, thereby promoting their practical applications in robust separation processes. Full article

Developing efficient photocatalysts is essential for sustainable wastewater treatment and tackling global water pollution. Graphitic carbon nitride (g-C₃N₄) is a promising material because it is active under visible light and chemically stable. However, its practical application is limited by fast recombination of charge carriers and a low surface area. In this study, we report a simple hydrothermal method to synthesize exfoliated porous g-C₃N₄ (E-PGCN) combined with Ti₃C₂ MXene to form a heterojunction composite that addresses these issues. Various characterization techniques (FTIR, XRD, XPS, SEM, BET) confirmed that adding MXene improves light absorption, increases surface area (53.7 m²/g for the composite versus 21.4 m²/g for bulk g-C₃N₄ (BGCN)), and enhances charge separation at the interface. Under UV-visible light irradiation with Rhodamine B (RhB) as the model pollutant, the E-PGCN/Ti₃C₂ MXene composite containing 3 wt% MXene demonstrated an impressive degradation efficiency of 93.2%. This performance is superior to BGCN (66.6%), E-PGCN (82.5%), and E-PGCN/Ti₃C₂ MXene-5 wt% composites (81%). This is due to the excess Mxene which caused agglomeration and reduced activity. Scavenger studies identified electron radicals as the dominant reactive species, with optimal activity at pH ~4.5. This enhanced performance, 1.4 times greater than BGCN and 1.13 times higher than E-PGCN, is ascribed to the synergistic interplay between the excellent electrical conductivity of MXene and the porous structural features of E-PGCN. This work highlights the importance of morphological engineering and heterojunction design for advancing metal-free photocatalysts, offering a scalable strategy for sustainable water purification. Full article

Photocatalytic CO₂ reduction holds great potential for sustainable solar fuel production, yet its practical application is often limited by inefficient charge separation and poor product selectivity. The photothermal effect presents a viable strategy to address these challenges by reducing activation energies and accelerating reaction kinetics. In this work, we report a rationally designed CN-B/Ti₃C₂ heterojunction that effectively leverages photothermal promotion for enhanced CO₂ reduction. The black carbon nitride (CN-B) framework, synthesized via a one-step calcination of urea and Phloxine B, exhibits outstanding photothermal conversion, reaching 131.4 °C under 300 mW cm⁻² illumination, which facilitates CO₂ adsorption and charge separation. Coupled with Ti₃C₂ MXene, the optimized composite (3:1) achieves remarkable CO and CH₄ production rates of 80.21 and 35.13 μmol g⁻¹ h⁻¹, respectively, without any cocatalyst—representing a 2.9-fold and 8.8-fold enhancement over CN-B and g-C₃N₄ in CO yield. Mechanistic studies reveal that the improved performance stems from synergistic effects: a built-in electric field prolongs charge carrier lifetime (3.15 ns) and reduces interfacial resistance, while localized heating under full-spectrum light further promotes CO₂ activation. In situ Fourier transform infrared (FTIR) spectroscopy confirms the accelerated formation of key intermediates (*COOH and *CO). The catalyst also maintains excellent stability over 24 h. This study demonstrates the promise of combining photothermal effects with heterojunction engineering for efficient and durable CO₂ photoreduction. Full article

Diabetes is a significant global health issue that demands accurate, accessible, and non-invasive diagnostic methods for effective prevention and treatment. Conventional diagnostic systems are often expensive, painful, time-consuming, and not universally available. In this study, we present a smart system for acetone estimation using simulated breath and a recurrent neural network (RNN) model. The detection system employs a new sensor fabricated from a composite of 1D nanostructured KWO (K₂W₇O₂₂) and 2D nanosheet MXene (Ti₃C₂), designed to measure the chemiresistive response to acetone by mimicking human breath. Resistance data collected by the sensor are used to compute sensitivity values for each acetone concentration (in parts per million, PPM). These values serve as input features for the RNN model, which learns to evaluate health as healthy, high-risk, or diabetic. Trained on acetone concentrations ranging from 0.4 to 2 PPM, the RNN achieves an R² of 99.41% in predicting potential for accurate breath acetone prediction. In future work, we aim to develop a smart device and mobile application based on this model to facilitate real-time diabetes monitoring and prediction. Full article