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MXenes belong to the potential family of two-dimensional materials with distinctive characteristics that make them appealing for various uses, especially in energy storage systems. Exploring two-dimensional (2D) components has expanded beyond graphene, encompassing extreme materials like phosphorene and its derivatives. Notably, the emergence of 2-dimensional titanium carbide (Ti 3 C 2), the pioneering member of the MXene family, offers specific structural and electrical properties conducive to diverse applications. MXenes, derived from selective layer etching through metal nitrides and carbides (MAX phases), exhibit a layered structure akin to graphene and electrical conductivity. With approximately a combination of 30 materials, it has been documented and observed that MXenes hold promise across industries such as Li-ion battery cells (LIBs), super-capacitors, catalysis, and hydrogen storage. This review systematically outlines production techniques, catalyst performance, and potential enhancements in MXene applications. Catalyst production methods yield promising results, with discussions on challenges and proposed solutions. Structural stability and diverse applications of MXenes, including batteries and catalysis, are explored, emphasizing morphological, optical, and electrical characteristics. Future research directions are recommended to address existing challenges and leverage this review as a guidepost for further investigation and advancement in MXene materials science. CuMnO 2 /MXene nanocomposite is a viable option for battery electrode material due to its excellent properties. CuMnO 2 combined oxides will increase the power density by acting as active sites, enhancing charge transportation of charge and rate capability, while MXene will increase electrical conductivity by enhancing cycling stability. This composite will be a promising candidate for positively impacting battery performance. [ABSTRACT FROM AUTHOR]

Due to the ubiquity of textiles in the lives, electronic textiles (E‐textiles) have emerged as a future technology capable of addressing a myriad of challenges from mixed reality interfaces, on‐garment climate control, patient diagnostics, and interactive athletic wear. However, providing sufficient electrical power in a textile form factor has remained elusive. To address this issue, different approaches are discussed, starting with supercapacitors' advantages and limitations and material choices for textile‐based supercapacitors before discussing proper data analysis and design considerations of textile‐based energy storage to power wearable electronics. [ABSTRACT FROM AUTHOR]

MXenes, the largest family of 2D transition metal carbides/nitrides, have emerged as promising materials for various applications due to their exceptionally fascinating properties. In this study, the potential of MXenes is investigated in plasmonic applications, particularly focusing on surface‐enhanced Raman scattering (SERS) and broadband photodetection. The study explored a broader range of light‐matter interactions based on edge plasmons that emerge at sub‐monolayer coverage of MXene, while existing studies have primarily focused on thicknesses exceeding tens of nanometers. Additionally, by incorporating MXenes onto 3D trench nanostructures, To maximize their plasmonic properties is aimed by enhancing the manifestation of edge plasmons, leading to intensified light amplification. The fabricated opto‐electronic devices exhibit remarkable sensitivity in SERS detection, achieving a detection limit as low as ≈0.1 nm for the target dye molecule, significantly surpassing typical thresholds for non‐metal‐based detection. Additionally, the enhancement factor exceeds that of commercially available Au‐based SERS substrates. Furthermore, MXene‐based photodetectors demonstrate competitive photoresponsivity and response time, particularly toward the near‐infrared (NIR) wavelength bands, which are challenging to achieve with MXene‐based photodetectors. Through a comprehensive analysis, including electric field calculations, the mechanisms driving the observed enhancements are unveiled, primarily attributing them to edge plasmons. [ABSTRACT FROM AUTHOR]

The pursuit of sustainable energy technologies has led to considerable interest in waste heat harvest from various energy sources. Thermocells (TECs), using the thermogalvanic effect, hold high potential in converting low‐grade heat directly into electricity. Optimizing thermopower and ensuring adaptability in low or sub‐zero temperature conditions are crucial for the advancement of next‐generation TECs. To address these challenges, in this work, a composite hydrogel electrolyte incorporating ethylene glycol (EG) and Ti3C2Tx MXene nanosheets is rationally engineered. EG boosts thermopower by increasing solvation entropy change and concentration ratio difference of redox ions; it also prevents freezing by disrupting hydrogen bonds among water molecules. Meanwhile, hydrophilic MXene nanosheets facilitate gelation process, improve mechanical strength, and further bond to water molecules to enhance anti‐freezing and moisture‐retaining capabilities. The TECs fabricated on this composite hydrogel electrolyte exhibit a notably increased thermopower of 2.04 mV K−1 and can be continuously operated at sub‐zero temperatures down to −40 °C. Electricity‐generating TEC windows are further demonstrated to harvest all‐day low‐grade heat via utilizing the temperature difference between the indoor and the outdoor. This study proposes an electrolyte engineering strategy for long‐lasting and reliable TECs that are suitable for low‐grade heat harvesting in extreme low‐temperature conditions. [ABSTRACT FROM AUTHOR]

MXenes are promising passive components that enable lithium‐sulfur batteries (LSBs) by effectively trapping lithium polysulfides (LiPSs) and facilitating surface‐mediated redox reactions. Despite numerous studies highlighting the potential of MXenes in LSBs, there are no systematic studies of MXenes' composition influence on polysulfide adsorption, which is foundational to their applications in LSB. Here, a comprehensive investigation of LiPS adsorption on seven MXenes with varying chemistries (Ti2CTx, Ti3C2Tx, Ti3CNTx, Mo2TiC2Tx, V2CTx, Nb2CTx, and Nb4C3Tx), utilizing optical and analytical spectroscopic methods is performed. This work reports on the influence of polysulfide concentration, interaction time, and MXenes' chemistry (transition metal layer, carbide and carbonitride inner layer, surface terminations and structure) on the amount of adsorbed LiPSs and the adsorption mechanism. These findings reveal the formation of insoluble thiosulfate and polythionate complex species on the surfaces of all tested MXenes. Furthermore, the selective adsorption of lithium and sulfur, and the extent of conversion of the adsorbed species on MXenes varied based on their chemistry. For instance, Ti2CTx exhibits a strong tendency to adsorb lithium ions, while Mo2TiC2Tx is effective in trapping sulfur by forming long‐chain polythionates. The latter demonstrates a significant conversion of intermediate polysulfides into low‐order species. This study offers valuable guidance for the informed selection of MXenes in various functional components benefiting the future development of high‐performance LSBs. [ABSTRACT FROM AUTHOR]

The heterojunctions based transition metal carbide (MXenes) provides new possibilities for achieving high-performance photodetector. The electronic, mechanical, optical, and photocatalytic properties of the Hf 2 CO 2 -based heterojunctions are calculated based on first-principles calculations, and the photocurrent (I ph) and extinction ratio (ER) are calculated based on quantum transport simulations. The Hf 2 CO 2 /Sc 2 CF 2 , Hf 2 CO 2 /Zr 2 CO 2 , and Hf 2 CO 2 /Sc 2 CCl 2 heterojunctions are ionic semiconductors with indirect bandgap. The Hf 2 CO 2 /Sc 2 CF 2 heterojunction exhibits high solar to hydrogen efficiency (η STH) of 40.14 % and applying biaxial strain can effectively modulate the η STH of the Hf 2 CO 2 /Zr 2 CO 2 heterojunction. The Hf 2 CO 2 /Zr 2 CO 2 heterojunction has low overpotentials (ηHER) of 0.19 V and exhibits high electron mobility. The photodetector based on the Hf 2 CO 2 /Zr 2 CO 2 heterojunction exhibits high I ph , and the photodetector based on the Hf 2 CO 2 /Sc 2 CF 2 heterojunction has large ER and sensitivity to infrared and ultraviolet polarized light. The I ph and ER are significant increase by bending the photodetector. Our research indicates the potential applications of the Hf 2 CO 2 -based heterojunctions in photocatalytic water splitting and photodetector. [Display omitted] [ABSTRACT FROM AUTHOR]

Finding appropriate photocatalysts for solar‐driven water (H2O) splitting to generate hydrogen (H2) fuel is a challenging task, particularly when guided by conventional trial‐and‐error experimental methods. Here, density functional theory (DFT) is used to explore the MXenes photocatalytic properties, an emerging family of two‐dimensional (2D) transition metal carbides and nitrides with chemical formula Mn+1XnTx, known to be semiconductors when having Tx terminations. More than 4,000 MXene structures have been screened, considering different compositional (M, X, Tx, and n) and structural (stacking and termination position) factors, to find suitable MXenes with a bandgap in the visible region and band edges that align with the water‐splitting half‐reaction potentials. Results from bandgap analysis show how, in general, MXenes with n = 1 and transition metals from group III present the most cases with bandgap and promising sizes, with C‐MXenes being superior to N‐MXenes. From band alignment calculations of candidate systems with a bandgap larger than 1.23 eV, the minimum required for a water‐splitting process, Sc2CT2, Y2CT2 (Tx = Cl, Br, S, and Se) and Y2CI2 are highlighted as adequate photocatalysts. [ABSTRACT FROM AUTHOR]

Herein, we present a density functional theory with dispersion correction (DFT‐D) calculations that focus on the intercalation of ionic liquids (ILs) electrolytes into the two‐dimensional (2D) Ti3C2Tx MXenes. These ILs include the cation 1‐ethyl‐3‐methylimidazolium (Emim+), accompanied by three distinct anions: bis(trifluoromethylsulfonyl)imide (TFSA−), (fluorosulfonyl)imide (FSA−) and fluorosulfonyl(trifluoromethanesulfonyl)imide (FTFSA−). By altering the surface termination elements, we explore the intricate geometries of IL intercalation in neutral, negative, and positive pore systems. Accurate estimation of charge transfer is achieved through five population analysis models, such as Hirshfeld, Hirshfeld‐I, DDEC6 (density derived electrostatic and chemical), Bader, and VDD (voronoi deformation density) charges. In this work, we recommend the DDEC6 and Hirshfeld‐I charge models, as they offer moderate values and exhibit reasonable trends. The investigation, aimed at visualizing non‐covalent interactions, elucidates the role of cation‐MXene and anion‐MXene interactions in governing the intercalation phenomenon of ionic liquids within MXenes. The magnitude of this role depends on two factors: the specific arrangement of the cation, and the nature of the anionic species involved in the process. [ABSTRACT FROM AUTHOR]

MXenes are prototypes of surface tunable 2D materials with vast potential for properties tuning. Accurately characterizing their surface functionalization and its role in electronic structure is crucial, X‐ray photoelectron spectroscopy (XPS) being among the go‐to methods to do so. Despite extensive use, XPS analysis remains however intricate. Focusing on the benchmark MXene Ti3C2Tz, Density Functional Theory (DFT) calculations of core‐level binding energy shifts (BE.s.) are combined with experiments in order to provide a quantitative interpretation of XPS spectra. This approach demonstrates that BE.s. are driven by the complex interplay between chemical, structural, and subtle electronic structure effects preventing analysis from intuitive arguments or comparison with reference materials. In particular, it is shown that O terminations induce the largest BE.s. at Ti 2p levels despite lower electronegativity than F. Additionally, F 1s levels show weak sensitivity to the F local environment, explaining the single contribution in the spectrum, whereas O 1s states are significantly affected by the local surface chemistry. Finally, clear indicators of surface group vacancies are given at Ti 2p and O 1s levels. These results demonstrate the combination of calculations with experiments as a method of the highest value for MXenes XPS spectra analysis, providing guidelines for otherwise complex interpretations. [ABSTRACT FROM AUTHOR]

Developing electrocatalysts with the trade-off between overall electrocatalytic performance and economic cost towards hydrogen evolution reaction (HER) is crucial for producing green hydrogen fuels. Although theoretical studies have reported the potential of two-dimensional (2D) MXenes for the HER, their electrocatalytic performance is still unsatisfactory for the particular application due to their low intrinsic active and MXene stacking. To address this problem, we herein modify the electronic structure and increase the interlayer spacing between 2D Ti 3 C 2 T x MXenes through ammonia (NH 3)-assisted hydrothermal approach. The effect of synthesis temperature on the nitrogen doping mechanism and electrochemical behaviors for the HER is systemically explored. As a result, the nitrogen (N)-doped Ti 3 C 2 T x MXene fabricated at 160 °C exhibits the highest HER activity among all 2D N-doped Ti 3 C 2 T x nanosheets with the overpotential/Tafel slope of 186.91 mV RHE /115.94 mV RHE dec−1 in an acidic solution. Due to the synergistic contribution of nitrogen, the N-doped Ti 3 C 2 T x -160 °C has mass activity of 337.95 mA mg−1 at 0.3 V RHE , being 27.50-fold higher than that of pristine Ti 3 C 2 T x. This work indicated that heteroatom doping is a facile but efficient approach for modulating the electronic structure and intrinsic activity of MXene-based materials for electrochemical reactions. [Display omitted] • Nitrogen-doped 2D Ti 3 C 2 T x MXenes are fabricated via a green hydrothermal route. • Effect of treatment temperature on nitrogen doping mechanism and properties of N-doped MXenes is explored. • Relationship between doping nitrogen types and electrochemical behaviors for HER is discussed. • A suitable temperature plays a vital role in optimizing the HER performance of N-doped MXenes. [ABSTRACT FROM AUTHOR]

A distinguishing feature of MAX phases and their MXene derivatives is their remarkable chemical diversity. This diversity, coupled with the 2D nature of MXenes, positions them as outstanding candidates for a wide range of electrochemical applications. Chemical disorder introduced by a solid solution can improve electrochemical behavior. Up to now, adding considerable amount of tungsten (W) in MAX phase and MXenes solid solutions, which can enhance electrochemical performance, proved challenging. In this study, the synthesis of M site Ti1‐xWx solid solution MAX phases are reported. The 211‐type (Ti1‐xWx)2AlC exhibits a disordered solid solution, whereas the 312‐type (Ti1‐xWx)3AlC2 displays a near‐ordered structure, resembling o‐MAX, with W atoms preferentially occupying the outer planes. Solid‐solution MXenes, Ti2.4W0.6C2Tz, and Ti1.6W0.4CTz, are synthesized via selective etching of high‐purity MAX powder precursors containing 20% W. These MXenes are evaluated as sodium‐ion battery anodes, with Ti1.6W0.4CTz showing exceptional capacity, outperforming existing multilayer MXene chemistries. This work not only demonstrates the successful integration of W in meaningful quantities into a double transition metal solid solution MAX phase, but also paves the way for the development of cost‐effective MXenes containing W. Such advancements significantly widen their application spectrum by fine‐tuning their physical, electronic, mechanical, electrochemical, and catalytic properties. [ABSTRACT FROM AUTHOR]

MXenes are a class of two-layered progress metal carbides/nitrides that offer unique properties for diverse applications, including electrocatalysis, supercapacitors, biosensors, water refinement, and many more. Here, we demonstrate a novel MXene@Bi2O3 heterostructure with boosted electrocatalytic activity for OER. Furthermore, pictures captured by electron microscopy demonstrated MXene's strong cooperation with Bi2O3. Additionally, the 2D MXene cooperation created extra pathways for mass transport during OER. Distinctive structure and the synergistic interaction between its components, MXene@Bi2O3 demonstrates remarkable electrocatalytic activity and durability in alkaline environments. With constant current density of 10 mAcm–2, the MXene@Bi2O3 catalyst showed outstanding catalytic activity and an overpotential of around 278 mV, which is 85 mV lower than the pure Bi2O3 catalyst. Combining Ti3C2Tx MXene with Bi2O3 led to increased intrinsic activity and accelerated charge transfer kinetics. This study proposes an effective approach for creating metal oxides and MXene hybrids with distinctive structures for electrocatalytic water splitting. The composite's exceptional electrochemical activity and durability suggest its potential as a very efficient electrocatalyst for water-splitting. Furthermore, this work's design and synthesis of hybrid composites with MXene-based nanomaterials opens up new opportunities for developing novel and efficient electrocatalysts in electrochemical applications. [ABSTRACT FROM AUTHOR]

We report a computational study of the bending deformation of two-dimensional nanoribbons by classical molecular dynamics methods. Two-dimensional double transition metal carbides, together with monometallic ones, belong to the family of novel nanomaterials, so-called MXenes. Recently, it was reported that within molecular dynamics simulations, Ti4C3 MXene nanoribbons demonstrated higher resistance to bending deformation than thinner Ti2C MXene and other two-dimensional materials, such as graphene and molybdenum disulfide. Here, we apply a similar method to that used in a previous study to investigate the behavior of Mo2Ti2C3 nanoribbon under bending deformation, in comparison to the Ti4C3 sample that has a similar structure. Our calculations show that Mo2Ti2C3 is characterized by higher bending rigidity at D Ti 2 Mo 2 C 3 ≈ 92.15 eV than monometallic Ti4C3 nanoribbon at D Ti 4 C 3 ≈ 72.01 eV, which has a similar thickness. Moreover, approximately the same magnitude of critical central deflection of the nanoribbon before fracture was observed for both Mo2Ti2C3 and Ti4C3 samples, w c ≈ 1.7 nm, while Mo2Ti2C3 MXene is characterized by almost two times higher critical value of related external force. [ABSTRACT FROM AUTHOR]

Graphene and MXenes have emerged as promising materials for gas sensing applications due to their unique properties and superior performance. This review focuses on the fabrication techniques, applications, and sensing mechanisms of graphene and MXene-based composites in gas sensing. Gas sensors are crucial in various fields, including healthcare, environmental monitoring, and industrial safety, for detecting and monitoring gases such as hydrogen sulfide (H2S), nitrogen dioxide (NO2), and ammonia (NH3). Conventional metal oxides like tin oxide (SnO2) and zinc oxide (ZnO) have been widely used, but graphene and MXenes offer enhanced sensitivity, selectivity, and response times. Graphene-based sensors can detect low concentrations of gases like H2S and NH3, while functionalization can improve their gas-specific selectivity. MXenes, a new class of two-dimensional materials, exhibit high electrical conductivity and tunable surface chemistry, making them suitable for selective and sensitive detection of various gases, including VOCs and humidity. Other materials, such as metal-organic frameworks (MOFs) and conducting polymers, have also shown potential in gas sensing applications, which may be doped into graphene and MXene layers to improve the sensitivity of the sensors. [ABSTRACT FROM AUTHOR]

Titanium carbide (Ti3C2Tx) MXene has attracted significant attention due to its exceptional properties and versatile solution processibility. However, MXene dispersions are prone to various degradation processes, leading to the formation of byproducts that negatively affect its morphological, electrical, and mechanical properties. Through the years, several methods have been developed to mitigate MXene degradation; however, divergent viewpoints on the understanding of degradation mechanisms are prevalent, hindering the development of versatile strategies in producing environmentally stable MXene dispersions. This review provides a chronological analysis of the research efforts aimed at unraveling the underlying mechanisms of MXene degradation and highlights strategies for circumventing this process. This review discusses apparent inconsistencies in experimental findings and theoretical models. These discrepancies prompt further investigation for a clearer understanding of the degradation process in MXene. This narrative allows readers to follow the evolution of dominant theories and disputes and to ultimately stimulate further investigation, aiming for a better understanding of this process. It is anticipated that identifying the fundamental factors affecting the oxidation of MXene dispersions will enable their full‐scale processing into higher‐order structures and practical devices with greater longevity and long‐term performance. [ABSTRACT FROM AUTHOR]

Friction and wear phenomena are common problems in sliding equipment, so materials with excellent antifriction and wear resistance properties are getting increasingly more attention. Two-dimensional (2D) materials, such as graphene and molybdenum disulfide, have always been the research hotspots on account of their special structures and excellent tribological properties. In 2011, MXene, an important member of the 2D material family, was launched. With excellent properties such as ultra-high strength, rich surface end groups, and relatively low cost, MXenes have great potential as lubricant additives. Although these properties have proved to be the reason why MXenes are impressive, the preparation of MXenes composites and the understanding of their mechanical and tribological mechanisms remain to be further investigated. In addition, the abundant surface end groups of MXenes nanosheets make them relatively easy to be functionalized, which has attracted widespread attention. This review aims to comprehensively understand the tribological properties of MXenes nanolayers and to summarize and sort out recent research progress. First, the preparation of MXenes is reviewed, and then the latest research progress of MXenes in liquid lubrication, solid lubrication, and solid–liquid hybrid systems since the advent of MXenes is summarized. Finally, some current problems are presented and an outlook on the development of MXenes is given. [ABSTRACT FROM AUTHOR]

[Display omitted] • The fabricated Ti 3 CN has enhanced physical and electronic properties and favorable zincophilic sites (N and F). • Ti 3 CN-protected Zn anode facilitate lateral growth of deposited zinc metal and rapid desolvation kinetics. • It presents a novel approach to designing protective layers for high-performance zinc anodes. Dendrite growth and side reactions of zinc metal anode have severely limited the practical application of aqueous zinc ion batteries (AZIBs). Herein, we introduce an artificial buffer layer composed of functional MXene (Ti 3 CN) for zinc anodes. The synthesized Ti 3 CN exhibits superior conductivity and features duplex zincophilic sites (N and F). These characteristics facilitate the homogeneous deposition of Zn2+, accelerate the desolvation process of hydrated Zn2+, and reduce the nucleation overpotential. The Ti 3 CN-protected Zn anode demonstrates significantly enhanced reversibility compared to bare Zn anode during long-term cycling, achieving a cumulative plating capacity of 10,000 mAh cm−2 at 10 mA cm−2. In Ti 3 CN-Zn||Cu asymmetric cell, it maintains nearly 100 % Coulombic efficiency over 2500 cycles at 2 mA cm−2. Furthermore, the assembled Ti 3 CN-Zn//δ-K 0.51 V 2 O 5 (KVO) full cell exhibit a low capacity decay rate of 0.002 % per cycle at 5 A/g. Even at 0 °C, the Ti 3 CN-Zn symmetric cell maintains steady cycling for 2000 h. This study introduces a novel approach for designing artificial solid electrolyte interlayers for commercial AZIBs. [ABSTRACT FROM AUTHOR]

MXenes, a novel class of 2D transition metal carbides and nitrides, have recently emerged as a promising candidate in the quest for efficient catalysts for the hydrogen evolution reaction. To enhance the performance of 2D MXenes with modest or poor catalytic efficiency, a particularly prosperous strategy involves doping with transition and noble metal atoms. Taking the Nb4C3O2 monolayer as a model, we explore substitutional metallic impurities, which serve as single-atom catalysts embedded within the Nb4C3O2 surface. Our findings demonstrate the ability to finely tune the atomic H binding energy within a 0.6 eV range, showing the potential for precise control in catalytic applications. Across different transition and noble metals, the single atoms integrated into Nb4C3O2 effectively adjust the free energy of H adsorption at nearby O atoms, achieving values comparable to or superior to Pt catalysts. A comprehensive examination of the electronic properties around the impurities reveals a correlation between changes in local reactivity and charge transfer to neighboring O atoms, where H atoms bind. [ABSTRACT FROM AUTHOR]

Due to the long‐range atomic disorder and more active sites, amorphous MXenes with better chemical reactivity and electrical conductivity, have attracted wide attention in energy storage devices. However, to reach the practical applications of MXenes, investigations into the best structure of the amorphous layer are essential. Here, the structure evolution of MXenes induced from ammonium persulfate is explored via synchrotron radiation X‐ray absorption spectroscopy. Then, a kind of oxygen‐poor amorphous heterojunction Nb2CTx MXene (a‐Nb2CTx) is designed. Benefitting from the oxygen‐poor amorphous heterojunction, the a‐Nb2CTx electrode exhibits excellent Li+ storage performance with a high discharge specific capacity of 382 mAh g−1 at 0.1 A g−1 and a long cycling stability of 300 mAh g−1 at 1.0 A g−1 after 800 cycles. Operando synchrotron X‐ray diffraction results reveal that oxygen‐poor amorphous heterojunction stabilizes Nb2CTx MXene from undergoing structural changes during cycling. This work provides new insights into the rational design of novel amorphous MXenes, which is of great significance for the development of MXenes and their applications in high‐performance energy storage systems. [ABSTRACT FROM AUTHOR]

Currently, over 60% of the world's population lives in cities. Urban living has many advantages but there are also challenges regarding the need for smart urbanization. The next generation of tunable 2D nanomaterials, called MXenes, is the critical enabling technology that can bring the current urban thinking to the next level, called a smart city. The smart city is a novel concept based on a framework of self‐sufficient technologies that are interactive and responsive to citizens’ needs. In this perspective, MXene‐enabled technologies for sustainable urban development are discussed. They can advance self‐sufficient, adaptive, and responsive buildings that can minimize resource consumption, solving the deficiency of essential resources such as clean energy, water, and air. MXenes are at the cutting edge of technological limitations associated with the Internet of Things (IoT) and telemedicine, combining diverse properties and offering multitasking. It is foreseen that MXenes can have a bright future in contributing to the smart city concept. Therefore, the roadmap is presented for demonstrating the practical feasibility of MXenes in the smart city. Altogether, this study promotes the role of MXenes in advancing the well‐being of citizens by raising the quality of urban living to the next level. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van der Waals (vdW) magnetic materials show potential for the advancement of high-density, energy-efficient electronic and spintronic applications in future memory and computation. Here, by using first-principles density functional theory (DFT) calculations, we predict a new 2D Janus nitride MXene MnCrNO2 monolayer. Our results suggest that the optimized MnCrNO2 monolayer possesses a hexagonal structure and exhibits good dynamical stability. The intrinsic monolayer MnCrNO2 exhibits semiconductive properties and adopts a ferromagnetic ground state with an out-of-plane easy axis. It can sustain strain effects within a wide range of strains from −10% to +8%, as indicated by the phonon dispersion spectra. Under the biaxial tensile strain, a remarkable decrease in the bandgap of the MnCrNO2 is induced, which is attributed to the distinct roles played by Mn and Cr in the VBM or CBM bands. Furthermore, when the compressive strain reaches approximately −8%, the magnetic anisotropy undergoes a transition from an out-of-plane easy axis to an in-plane easy axis. This change is mainly influenced by the efficient hybridization of the d orbitals, particularly in Mn atoms. Our study of the Janus MXene MnCrNO2 monolayer indicates its potential as a promising candidate for innovative electronic and spintronic devices; this potential is expected to create interest in its synthesis. [ABSTRACT FROM AUTHOR]

MXenes, with a particular emphasis on Ti3C2 (M3X2) have been extensively studied and established as the foundational material for 2D MXenes. However, the exploration of other transitional metals as 2D MXenes holds great promise, offering applications beyond the existing knowledge. Non‐Ti (M2X and M3X2) MXenes have garnered attention due to their distinctive properties. This review article focuses on explaining the potential and challenges of non‐Ti (M2X and M3X2) MXenes in energy storage and conversion systems, specifically in the domains of supercapacitors, batteries (Li‐ion and Li‐S), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR). By providing a comprehensive overview of the current progress and addressing the associated challenges, this review offers valuable insights into the future prospects of not only non‐Ti (M2X and M3X2) MXenes but also other MXenes for energy storage and conversion. The findings presented herein pave the way for further research and multifaceted applications of these MXenes across various fields. [ABSTRACT FROM AUTHOR]

The booming development of mobile devices has remarkably improved the lives of people, but it also leads to severe electromagnetic radiation problems. Therefore, it has become significantly important to develop electromagnetic interference (EMI) shielding materials for electromagnetic protection. In recent years, MXenes have attracted much attention in the field of EMI shielding, owing to outstanding electrical conductivity, high specific surface area and hydrophilicity. Firstly, this review introduces EMI shielding mechanism and categorization of EMI shielding materials. Subsequently, the research progress of MXenes/polymer‐based EMI shielding materials is reviewed in detail, especially for preparation methods of MXenes/polymer‐based EMI shielding blocks. Finally, the key scientific problems in MXenes/polymer‐based EMI shielding materials are proposed, and their development trend are prospected. Highlights: The EMI shielding mechanism and categorization of EMI shielding materials is presented.The latest research progress of MXenes/polymer‐based EMI shielding materials is reviewed.Scientific problems for MXenes/polymer‐based EMI shielding materials are proposed.Development trend of MXenes/polymer‐based EMI shielding materials is prospected. [ABSTRACT FROM AUTHOR]

Electronic skin is increasingly receiving tremendous attention for its potential applications in medical rehabilitation and human‐machine interaction. However, the trade‐off between detection range and sensitivity of e‐skin has not been well addressed, although various strategies have been proposed. Interlocked microridges between the epidermis and dermis can effectively transfer stress to mechanoreceptors, allowing human skin to exhibit excellent sensitivity even upon both subtle and large external stimuli. Herein, inspired by human skin, a novel bionic e‐skin is developed in which interlocked microridges are introduced between the sensitive layer and interdigitated electrode. Thanks to the interlocked microridges, excellent compression capability and remarkable change of contact area between sensitive layer and interdigitated electrode can be achieved and the e‐skin exhibits an ultrahigh sensitivity (≈1502.5 kPa−1), excellent durability (10 000 cycles), a short response time (10 ms) as well as a wide detection range (≈160 kPa). Moreover, due to the effective transmission of external stress from a sensitive layer to an interdigitated electrode, such bionic e‐skin has ability to detect a wide range of human vital signs and vibrations caused by sound waves. Such facile preparation of bionic interlocked microridges opens a new pathway to achieve high‐performance e‐skins and extend their application prospects in future wearable intelligent systems. [ABSTRACT FROM AUTHOR]

This research examines vanadium‐deficient V2C MXene, a two‐dimensional (2D) vanadium carbide with exceptional electrochemical properties for rechargeable zinc‐ion batteries. Through a meticulous etching process, a V‐deficient, porous architecture with an expansive surface area is achieved, fostering three‐dimensional (3D) diffusion channels and boosting zinc ion storage. Analytical techniques like scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller, and X‐ray diffraction confirm the formation of V2C MXene and its defective porous structure. X‐ray photoelectron spectroscopy further verifies its transformation from the MAX phase to MXene, noting an increase in V3+ and V4+ states with etching. Cyclic voltammetry reveals superior de‐zincation kinetics, evidenced by consistent V3+/V4+ oxidation peaks at varied scanning rates. Overall, this V‐deficient MXene outperforms raw MXenes in capacity and rate, although its capacity diminishes over extended cycling due to structural flaws. Theoretical analyses suggest conductivity rises with vacancies, enhancing 3D ionic diffusion as vacancy size grows. This work sheds light on enhancing V‐based MXene structures for optimized zinc‐ion storage. [ABSTRACT FROM AUTHOR]

Through density functional theory calculations, the mechanism of CO oxidation to CO2 on single‐atom catalysts consisting of an atom of Ti, Fe, or Zn deposited on the surface of the Mo2CO2 MXene is investigated. In the case of Fe@Mo2CO2, a mechanism resembling that of Termolecular Langmuir–Hinshelwood (TLH) is thermodynamically and kinetically favored, displaying very exothermic CO2 formation, low activation energies, and easy CO2 desorption. On Ti@Mo2CO2, the dissociation of CO2 is almost barrierless and much more likely to occur than CO2 desorption, barring the usage of this surface as a catalyst for CO oxidation. Finally, on Zn@Mo2CO2, a hybrid Langmuir–Hinshelwood/Eley–Rideal (LH/ER) mechanism is thermodynamically and kinetically feasible. Here, after the first CO2 forms, with an energy barrier of only 0.62 eV, the second CO2 is formed spontaneously, and the Zn–CO2 interactions are weak enough to allow desorption. The calculated thermodynamic quantities and reaction rates at T = 300 K indicate that Fe@Mo2CO2 should be quite active toward CO oxidation, followed by Zn@Mo2CO2, while the Ti‐based model is inactive. The results add to the evidence that establishes single transition metal atoms adsorbed on MXene surfaces as cheap and easily obtainable catalysts that offer the best of both bare and functionalized MXenes. [ABSTRACT FROM AUTHOR]

Layered Ti3C2Tx MXene has been successfully intercalated and exfoliated with the simultaneous generation of a 3D silica network by treating its cationic surfactant intercalation compound (MXene-CTAB) with an alkoxysilane (TMOS), resulting in a MXene–silica nanoarchitecture, which has high porosity and specific surface area, together with the intrinsic properties of MXene (e.g., photothermal response). The ability of these innovative MXene silica materials to induce thermal activation reactions of previously adsorbed compounds is demonstrated here using NIR laser irradiation. For this purpose, the pinacol rearrangement reaction has been selected as a first model example, testing the effectiveness of NIR laser-assisted photothermal irradiation in these processes. This work shows that Ti3C2Tx-based nanoarchitectures open new avenues for applications that rely on the combined properties inherent to their integrated nanocomponents, which could be extended to the broader MXene family. [ABSTRACT FROM AUTHOR]

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Abstract The hydrogen storage potential of the bare MXenes Y2C and terminated Y2CT2, where T is O, OH, or F, were studied using density functional theory (DFT). Hydrogen adsorption and desorption behaviors are simulated by ab initio molecular dynamic simulations. The interaction of the H2-molecules on the Y2C-family was investigated within the projected density of states. Only bare Y2C and Y2C(OH)2 provided Kubas-type interactions. The calculated maximum capacity of H2 in bare Y2C can reached up to 5.041 wt%, whereas the reversible capacity of H2 was up to 2.036 wt%. In Y2C(OH)2, the maximum capacity of H2 storage is 3.477 wt% and the reversible capacity was 1.769 wt%. This indicated that Y2C and Y2C(OH)2 are practical candidates for hydrogen storage applications.

[Display omitted] • Physicochemical excellence of MXenes demonstrating their multi-dimensionality in wide range of applications. • Controlling the physicochemical properties of MXenes to enhance the catalytic efficiency of MXenes materials. • Energy-driven applications of MXenes hybrids in photochemical/electrochemical CO 2 RR and HER applications. • Theoretical modelling and experimental achievements of MXenes for attaining new heights of sustainability. The dawn of MXenes has fascinated researchers under their intriguing physicochemical attributes that govern their energy and environmental applications. Modifications in the physicochemical properties of MXenes pave the way for efficient energy-driven operations such as carbon capture and hydrogen generation. The physicochemical modulations such as interface engineering through van der Waals coupling with homo/hetero-junctions render the tunability of optoelectronic variables driving the photochemical and electrochemical processes. Herein, we have reviewed the recent achievements in physicochemical properties of MXenes by highlighting the role of intercalants/terminal groups, atomic defects, surface chemistry and few/mono-layer formation. Recent findings of MXenes-based materials are systematically surveyed in a tandem manner with the future outlook for constructing next-generation multi-functional catalytic systems. Theoretical modelling of MXenes surface engineering proffers the mechanistic comprehension of surface phenomena such as termination, interface formation, doping and functionalization, thereby enabling the researchers to exploit them for targeted applications. Therefore, theoretical anticipations and experimental evidences of electrochemical/photochemical carbon dioxide reduction and hydrogen evolution reactions are synergistically discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The stability of 14 single metal depositions on Mo 2 TiC 2 O 2 support is compared. • CH4 adsorption is thermodynamically favorable on all simulated Mo 2 TiC 2 O 2 SACs. • Ru-, Rh-, Co-, V-, Cr-, Ti-, and Pt-SACs are promising catalysts for CH 4 activation. • Four SACs show potential for further testing as cost-effective catalysts. • Our results are also applicable to other alkane dehydrogenation processes. Producing value-added chemicals and fuels from methane (CH 4) under mild conditions efficiently utilizes this cheap and abundant feedstock, promoting economic growth, energy security, and environmental sustainability. However, the first C H bond activation is a significant challenge and requires high energy. Efficient catalysts have been sought for utilizing CH 4 at low temperatures including emerging single-atom catalysts (SACs). In this work, we screened fourteen transition metals (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Pt) doped at a single oxygen vacancy in Mo 2 TiC 2 O 2 (TM SA -Mo 2 TiC 2 O 2 SACs) for methane activation using density functional theory (DFT) calculations. Our results reveal that methane adsorption is thermodynamically stable on all simulated TM SA -Mo 2 TiC 2 O 2 SACs, with the adsorption energies (E ads) ranging from −0.92 to −0.40 eV. For the C H activation process, Ru-SAC exhibits the lowest activation barrier (E a) of 0.22 eV. In summary, Ru-, Rh-, Co-, V-, Cr-, Ti-, and Pt-SACs demonstrate promising catalytic properties for methane activation, with E a values below 1.0 eV and an exothermic nature. Our findings pave the way for the design and development of novel single-atom catalysts in MXene materials, applicable not only for methane activation but also for other alkane dehydrogenation processes. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of efficient and stable electrocatalysts is crucial for the advancement of green and clean hydrogen energy technologies. In this work, we synthesized a nanocomposite of nickel–iron layered double hydroxide/molybdenum titanium carbide (NiFe-LDHs/Mo 2 Ti 2 C 3) using a deep eutectic solvent (DESs) by the solvothermal method. The formation of NiFe-LDHs/Mo 2 Ti 2 C 3 nanocomposite was confirmed by various electron microscopic and spectroscopic techniques. The synthesized nanocomposite was investigated as a bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under the alkaline condition. The NiFe-LDHs/Mo 2 Ti 2 C 3 -based electrodes exhibit small overpotentials of 204 and 306 mV for HER and OER at a current density of 10 mA cm−2. The anchor of NiFe-LDHs on the surface of Mo 2 Ti 2 C 3 induces an interfacial synergistic effect, leading to a significantly improvement in electrochemical performance. Remarkably, the proposed NiFe-LDHs/Mo 2 Ti 2 C 3 modified electrode demonstrates superior performance compared to many recently reported LDHs and MXenes-based electrocatalysts in an alkaline environment. Furthermore, a symmetrical two-electrode water splitting setup employing the NiFe-LDHs/Mo 2 Ti 2 C 3 electrocatalyst requires an electrolysis voltage of 1.65 V to achieve a current density of 10 mA cm−2. The findings provide a new perspective on the rational design and synthesis of multifunctional electrocatalysts for electrochemical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] The challenge of achieving high-performance electromagnetic interference (EMI) shielding films, which focuses on electromagnetic waves absorption while maintaining thin thickness, is a crucial endeavor in contemporary electronic device advancement. In this study, we have successfully engineered hybrid films based on MXene nanosheets and Fe 3 O 4 nanoparticles, featuring intricate electric–magnetic dual-gradient structures. Through the collaborative influence of a unique dual-gradient structure equipped with transition and reflection layers, these hybrid films demonstrate favorable impedance matching, abundant loss mechanisms (Ohmic loss, interfacial polarization and magnetic loss), and an "absorb-reflect-reabsorb" process to achieve absorption-dominated EMI shielding capability. Compared with the single conductive gradient structure, the dual-gradient structure effectively enhances the absorption intensity per unit thickness, and thus reduces the thickness of the film. The optimized film demonstrates a remarkable EMI shielding effectiveness (SE) of 49.98 dB alongside an enhanced absorption coefficient (A) of 0.51 with a thickness of only 180 μm. The thin films with a dual-gradient structure hold promise for crafting absorption-dominated electromagnetic shielding materials, highlighting the potential for advanced electromagnetic protection solutions. [ABSTRACT FROM AUTHOR]

Mycotoxin pollution in agricultural food products endangers animal and human health during the supply chains, therefore the development of accurate and rapid techniques for the determination of mycotoxins is of great importance for food safety guarantee. MXenes-based nanoprobes have attracted enormous attention as a complementary analysis and promising alternative strategies to conventional diagnostic methods, because of their fascinating features, like high electrical conductivity, various surface functional groups, high surface area, superb thermal resistance, good hydrophilicity, and environmentally-friendlier characteristics. In this study, we outline the state-of-the-art research on MXenes-based probes in detecting various mycotoxins like aflatoxin, ochratoxin, deoxynivalenol, zearalenone, and other toxins as a most commonly founded mycotoxin in the agri-food supply chain. First, we present the diverse synthesis approaches and exceptional characteristics of MXenes. Afterward, based on the detecting mechanism, we divide the biosensing utilizations of MXenes into two subcategories: electrochemical, and optical biosensors. Then their performance in effective sensing of mycotoxins is comprehensively deliberated. Finally, present challenges and prospective opportunities for MXenes are debated. [ABSTRACT FROM AUTHOR]

In recent years, MXenes has been recognized as a promising material due to its unique physical and chemical properties. Compared with traditional two-dimensional nanomaterials, MXenes has the advantages of large specific surface area, high hydrophilicity, abundant surface active sites, and excellent chemical stability, which makes it have a wide application prospect in environmental remediation technologies such as adsorption. In this paper, the structure and physicochemical properties of MXenes were introduced. The research progress of MXenes for water pollution adsorption remediation was reviewed. The current status of adsorption treatment of heavy metals, dyes, radioactive substances and antibiotics by MXene-based adsorption materials were listed. The characteristics, adsorption conditions, adsorption capacity and corresponding adsorption mechanism of each adsorbent were introduced.The reuse ability of MXenes was discussed. On this basis, the challenges and prospects of MXenes application in the field of water treatment were discussed.

Liquid water under nanoscale confinement has attracted intensive attention due to its pivotal role in understanding various phenomena across many scientific fields. MXenes serve an ideal paradigm for investigating the dynamic behaviors of nanoconfined water in a hydrophilic environment. Combining deep neural networks and an active learning scheme, here we elucidate the proton‐driven dynamics of water molecules confined between V2CTx sheets using molecular dynamics simulation. Firstly, we have found that the Eigen and Zundel cations can inhibit water‐induced oxidation by adjusting the orientation of water molecules, thus proposing a general antioxidant strategy. Besides, we also identified a hexagonal ice phase with abnormal bonding rules at room temperature, rather than only at ultralow temperatures as other studies reported, and further captured the proton‐induced water phase transition. This highlighted the importance of protons in the maintaining stable crystal phase and phase transition of water. Furthermore, we discussed the conversions of different water structures and water diffusivity with changing proton concentrations in detail. The results provide useful guidance in practical applications of MXenes including developing antioxidant strategies, identifying novel 2D water phases and optimizing energy storage and conversion. [ABSTRACT FROM AUTHOR]

Hydrogen‐driven energy is fascinating among the everlasting energy sources, particularly for stationary and onboard transportation applications. Efficient hydrogen storage presents a key challenge to accomplishing the sustainability goals of hydrogen economy. In this regard, solid‐state hydrogen storage in nanomaterials, either physically or chemically adsorbed, has been considered a safe path to establishing sustainability goals. Though metal hydrides have been extensively explored, they fail to comply with the set targets for practical utilization. Recently, MXenes, both in bare form and hybrid state with metal hydrides, have proven their flair in ascertaining the hydrides′ theoretical and experimental hydrogen storage capabilities far beyond the fancy materials and current state‐of‐the‐art technologies. This review encompasses the significant accomplishments achieved by MXenes (primarily in 2019–2024) for enhancing the hydrogen storage performance of various metal hydride materials such as MgH2, AlH3, Mg(BH4)2, LiBH4, alanates, and composite hydrides. It also discusses the bottlenecks of metal hydrides for hydrogen storage, the potential use of MXenes hybrids, and their challenges, such as reversibility, H2 losses, slow kinetics, and thermodynamic barriers. Finally, it concludes with a detailed roadmap and recommendations for mechanistic‐driven future studies propelling toward a breakthrough in solid material‐driven hydrogen storage using cost‐effective, efficient, and long‐lasting solutions. [ABSTRACT FROM AUTHOR]

Correlative methods to characterize single entities by electrochemistry and microscopy/spectroscopy are increasingly needed to elucidate structure‐function relationships of nanomaterials. However, the technical constraints often differ depending on the characterization techniques to be applied in combination. One of the cornerstones of correlative single‐entity electrochemistry (SEE) is the substrate, which needs to achieve a high conductivity, low roughness, and electrochemical inertness. This work shows that graphitized sputtered carbon thin films constitute excellent electrodes for SEE while enabling characterization with scanning probe, optical, electron, and X‐ray microscopies. Three different correlative SEE experiments using nanoparticles, nanocubes, and 2D Ti3C2Tx MXene materials are reported to illustrate the potential of using carbon thin film substrates for SEE characterization. The advantages and unique capabilities of SEE correlative strategies are further demonstrated by showing that electrochemically oxidized Ti3C2Tx MXene display changes in chemical bonding and electrolyte ion distribution. [ABSTRACT FROM AUTHOR]

Real‐time detection of different physiological characteristics is crucial for human physical and mental health. A detection system with multimodal sensing capability, high sensitivity, excellent mechanical properties, and environmental stability is highly desirable, but it is still a great challenge. Inspired by the structural gradient of biological tissues, a multifunctional sensor based on carboxylic styrene butadiene rubber (XSBR) and sodium polyacrylate (PAANa) non‐covalently modified MXenes is prepared in this study, in which the MXenes exhibit a gradient distribution and simultaneously formed an orientation arrangement at the bottom of the matrix through the formation of hydrogen bonding interactions with PAANa. The material shows a considerable stretchability of 244% and strength of 7.67 MPa, high electrical conductivity of 55.40 S m‒1, low percolation threshold of 2.48 wt%, and excellent response to strain (gauge factor of 906.7 within 98% strain) and humidity (relative resistance change of 530% within 11–93% relative humidity). Based on the superior performances of the XSBR/PAANa/MXene composite, an integrated detection system is designed to accurately detect respiration and body movements at various scales. This work provides a new perspective for the development of a novel biomimetic functional material for sensor applications. [ABSTRACT FROM AUTHOR]

2D layered MXene‐based materials are applied as cation‐intercalation electrode materials for sodium‐ion batteries (SIBs) due to their layered structures but suffer from spontaneous restacking during Na+ insertion and deintercalation processes, resulting in sluggish reaction kinetics and poor cycling stability. Herein, fullerene C60 is intercalated covalently into the interlayer of Ti3C2Tx MXene nanosheets by using a low‐temperature hydrothermal reaction between a water‐soluble C60 derivative and hydrophilic MXene nanosheets, resulting in enlarged interlayer spacing of MXene nanosheets from 12.8 to 14.1 Å and consequently retarded self‐restacking. Moreover, the strong electron extraction ability of C60 facilitates electron transfer from MXene to C60, enabling faster charge transport during Na+ transportation. The as‐prepared C60@MXene hybrid is applied as a novel anode of SIBs, exhibiting outstanding electrochemical performance and super‐long cycling stability. C60@MXene‐based SIB delivers a specific capacity of 226.8 mAh g−1 at 0.1 A g−1 after 300 cycles, which surpasses that obtained from the pristine MXene anode, and retains 94.5% capacity at 1 A g−1 after 10 000 cycles. DFT simulations confirm that C60‐induced enlarged interlayer spacing benefits Na+ migrations, which is responsible for improved electrochemical performance and cycling stability. [ABSTRACT FROM AUTHOR]

Pristine Mo2C MXene has been proposed as an heterogeneous catalysis of the reverse water gas shift (RWGS) reaction. The present computational study aims at understanding its catalytic performance and reaction mechanisms tackling its thermodynamics, kinetics, and surface dynamic effects, combining Gibbs free energy profiles gained by density functional theory (DFT), mean‐field kinetics by microkinetic modeling, and rare‐event steps by kinetic Monte Carlo (kMC). The RWGS endergonicity goes for the use of high temperatures and reactants partial pressures to make the reaction exergonic. Gibbs free energy profiles show a preference for redox mechanism, whereas microkinetic simulations favor a low‐temperature preference of formate mechanism. The kMC reveals simultaneous operating redox and formate pathways, where surface coverage disfavors redox favoring the formate pathway. A peak performance is found at 700 K, in line with reported experiments, where the formation of surface O2* is found to be key, acting as a reservoir for O* adatoms while freeing surface sites upon O2* formation. Even though high turnover frequencies are predicted, the system could benefit from swing operando conditions, alternating CO production steps with H2 reduction regeneration steps, and/or ways to reduce the surface O2* and so to have more active catalytic sites. [ABSTRACT FROM AUTHOR]

Mxenes has attracted wide attention due to its advantages of high conductivity, diverse composition, thinness and adjustable structure. In this paper, we systematically calculated adsorption energy, Gibbs free energy, and exchange current density of Ti 3 C 2 O 2 and Ti 4 C 3 O 2. The effect of H-coverage, element (Cr, Hf, Mo, Nb, Ta, V) doping and strain application on the HER catalytic performance were also analyzed. The results show that Ti 4 C 3 O 2 has stronger catalytic ability than Ti 3 C 2 O 2. H coverage is negatively correlated with catalytic performance of Ti n+1 C n O 2 (n = 2, 3). Among calculated doping elements, for improving catalytic ability of Ti 3 C 2 O 2 , V or Mo doping is beneficial. While for Ti 4 C 3 O 2 , only Mo doping is beneficial. Furthermore, compression strain of −5%, −3%, −1% is beneficial for improving catalytic performance of Ti 3 C 2 O 2 and Ti 4 C 3 O 2. Our work reveals the microscopic mechanism of MXene catalyzing HER, which is useful for the further development of water electrolysis catalysts. [Display omitted] • Catalytic properties of Tin+1CnO2 (n = 2, 3) were systematically calculated & compared • Ti4C3O2 shows better catalytic performance than Ti3C2O2 • H coverage is negatively correlated with catalytic performance of Tin+1CnO2 (n = 2, 3) • V, Mo for Ti3C2O2, Mo for Ti4C3O2 can improve the catalytic performance • Compression strain of -5%, -3%, -1% is beneficial for Ti3C2O2 and Ti4C3O2 catalysts [ABSTRACT FROM AUTHOR]

The rationale for low performances in perovskite solar cells with buried interface still needs to be clarified, owing to the complicated physiochemistry of metal oxides/perovskite interface, and literature offers a meager knowledge about the reactions at this interface. While exploring the SnO2/perovskite interfacial interactions, the reasons behind deteriorating perovskite at the interface are comprehensively investigated, and it is revealed that the PbI2 residue and metallic Pb0 are the byproducts of this decomposed perovskite. Introducing an optimized amount of Ti3C2TX at the SnO2/perovskite interface detaches the SnO2 hydroxyls, which are found to be responsible for interfacial ion migrations. In addition, Ti3C2TX passivates the interface defects via its functional groups and establishes ballistic pathways for electrons with high chances of non‐radiative recombination. Thus, 25.19% (certified as 24.41%) of efficiency with superior long‐term operational stability is achieved. [ABSTRACT FROM AUTHOR]

The rationale for low performances in perovskite solar cells with buried interface still needs to be clarified, owing to the complicated physiochemistry of metal oxides/perovskite interface, and literature offers a meager knowledge about the reactions at this interface. While exploring the SnO2/perovskite interfacial interactions, the reasons behind deteriorating perovskite at the interface are comprehensively investigated, and it is revealed that the PbI2 residue and metallic Pb0 are the byproducts of this decomposed perovskite. Introducing an optimized amount of Ti3C2TX at the SnO2/perovskite interface detaches the SnO2 hydroxyls, which are found to be responsible for interfacial ion migrations. In addition, Ti3C2TX passivates the interface defects via its functional groups and establishes ballistic pathways for electrons with high chances of non‐radiative recombination. Thus, 25.19% (certified as 24.41%) of efficiency with superior long‐term operational stability is achieved. [ABSTRACT FROM AUTHOR]

Hydrogen is rapidly emerging as a clean and versatile energy carrier addressing challenges of climate change and energy sustainability. With increasing energy demand and rising application of hydrogen energy, safety while harnessing hydrogen energy is a primary concern. To enhance safety, it is critical to detect hydrogen gas during its leakage which is otherwise challenging due to its colourless, odourless and inflammable nature. Hence, there is an urgent need for the development of hydrogen sensors for rapid response, maximum absorption/desorption, high selectivity, a wide dynamic range, and a low detection limit. This review provides a comprehensive analysis of emerging nanomaterials and their composites spanning from 0D to 3D for hydrogen sensing, emphasizing the underlying mechanisms. It also deliberates on the advantages and disadvantages of a wider range of advanced materials including noble metals, metal oxide semiconductors (MOS), transition metal dichalcogenides (TMD), metal organic frameworks (MOF), Xenes and MXenes pondering over hysteresis phenomenon, commonly observed as a limitation of noble metal-based hydrogen sensors. Among these emerging materials, two dimensional nanomaterials stand out as the optimal choice for hydrogen sensing due to their large surface area, exceptional electrical properties, low operating temperatures, and ease of chemical modification. Carbon-based materials, TMDs, MOFs, and MXenes have higher gas absorption capability and excellent mechanical properties, making them suitable for low/room temperature sensing and wearable sensing platforms. The review underscores the need for reliable sensing materials and presents challenges in quantitative detection of hydrogen offering future directions for research in this field. [Display omitted] • The review features the urge to develop hydrogen sensors. • It spans a wide range of new materials used for hydrogen sensing over the last two decades. • The mechanism of hydrogen adsorption & desorption is elaborated. • The article highlights challenges & prospects of materials for hydrogen sensing. • This article is useful to researchers, scientists, and engineers working in this field. [ABSTRACT FROM AUTHOR]

As a rapidly expanding family of 2D materials, MXenes have recently gained considerable attention. Herein, by developing a coating method that enables transfer‐free and layer‐by‐layer film coating, the nonlinear optical absorption (NOA) of Ti3C2Tx MXene films is investigated. Using the Z‐scan technique, the NOA of the MXene films is characterized at ≈800 nm. The results show that there is a strong and layer‐dependent NOA behavior, transitioning from reverse saturable absorption (RSA) to saturable absorption (SA) as the layer number increases from 5 to 30. Notably, the nonlinear absorption coefficient β changes significantly from ≈7.13 × 102 cm GW−1 to ≈−2.69 × 102 cm GW−1 within this range. The power‐dependent NOA of the MXene films is also characterized, and a decreasing trend in β is observed for increasing laser intensity. Finally, the NOA of 2D MXene films at ≈1550 nm is characterized by integrating them onto silicon nitride waveguides, where an SA behavior is observed for the films including 5 and 10 layers of MXene, in contrast to the RSA observed at ≈800 nm. These results reveal intriguing nonlinear optical properties of 2D MXene films, highlighting their versatility and potential for implementing high‐performance nonlinear photonic devices. [ABSTRACT FROM AUTHOR]

Luteolin (Lu), a compound with various biochemical and pharmacological activities beneficial to human health, has attracted researchers' attention. This study proposes an efficient and scalable method using ultrasound to intercalate graphene oxide (GO)-coated silica spheres (SiO2) into MXenes, resulting in a 3D conductive interconnected structural composite material. Characterization of the composite material was conducted using SEM, TEM, XRD, XPS, and Raman spectroscopy. MXenes exhibit excellent electrical conductivity, and the SiO2@GO surface with abundant hydroxyl and silanol groups provides high-binding active sites that facilitate Lu molecule enrichment. The formation of the 3D conductive interconnected structural composites enhances charge transport, significantly improving sensor sensitivity. Consequently, the sensor demonstrates excellent detection capabilities (detection range 0.03–7000 nM, detection limit 12 pM). Furthermore, the sensor can be applied to quantitative determination of Lu in real samples, including chrysanthemums, Jiaduobao, honeysuckle, purple perilla, and peanut shells, achieving recoveries between 98.2 and 104.7%. [ABSTRACT FROM AUTHOR]

Bacterial infections are a great threat to human health, and the irrational use of antibiotics has largely compromised the efficacy of antibiotic therapy due to the emergence of drug‐resistant pathogens. It is known that synthesizing new antibiotics is difficult and time‐consuming. In this case, developing antibiotics‐independent antibacterial approaches is of great importance and significance. In the past decade, various functional nanomaterials have shown great potentials in the treatment of bacterial infections. Among these nanomaterials, transition metal carbides or nitrides, namely MXene, have attracted much attention. As the novel 2D nanosheets, MXene can serve either as a direct antibacterial agent due to its intrinsic antibacterial activity and photothermal effect, or as an efficient carrier to load photosensitizers and photocatalysts for photodynamic and photocatalytic therapy. In recent few years, the number of literatures regarding MXene‐based antibacterial therapy has increased rapidly. Thus, it is the time to systematically summarize the applications of MXene in the treatment of bacteria, especially those with drug resistance. Herein, it is aimed to summarize the preparation methods for MXene and provide a comprehensive understanding of its properties and applications in antibacterial therapy. Also, its use for bacterial detection and the challenges for practical use are discussed. [ABSTRACT FROM AUTHOR]

The growing need for efficient energy storage has spurred advancements in supercapacitors (SCs), aiming to offer high power and energy density simultaneously. While SCs offer longer cycles and higher power density values, their low energy densities limit practical applications. In response, pseudocapacitive materials have emerged, leveraging reversible Faradaic reactions at or near the surface for enhanced energy storage. This approach surpasses the constraints of the electrical double layer in SCs and the mass transfer constraints of batteries. Progress in asymmetric supercapacitors and high mass loading has improved energy density values, yet maintaining high mass loading without compromising power density remains a hurdle. Advancements in pseudocapacitance through intercalation during charging/discharging processes, especially in layered structures like graphite, graphene, transition metal oxides (TMOs) transition metal dichalcogenides (TMDCs), MXenes, and metal–organic frameworks (MOFs) have proven significant. The intercalated species induce reversible or irreversible structural changes, contributing to the physicochemical characteristics of the electrode materials. Exploring the intercalation mechanism in bulk two‐dimensional (2D) materials reveals distinct differences that enhance our understanding and improve electrochemical properties for superior energy storage. Finally, an in‐depth exploration of the intercalation pseudocapacitance in 2D materials such as TMDCs and MXenes underscores their significance, setting a benchmark for future electrochemical studies in the subsequent advancement of SCs research. [ABSTRACT FROM AUTHOR]

This comprehensive review provides a novel and insightful perspective on the utilization of MXenes, a fascinating class of two-dimensional (2D) transition metal carbides and nitrides, for the electrochemical sensing of glucose (GU) and dopamine (DA). The novelty of this work lies in the detailed examination of MXenes' exceptional properties, including their remarkable electrical conductivity and tunable surface chemistry, which set them apart from conventional materials. Additionally, the review explores a diverse range of synthesis methods, such as the etching of MAX phases and direct synthesis approaches, highlighting their versatility and adaptability to specific sensing requirements. The paper also meticulously investigates the influence of various synthesis parameters on the distinctive properties of MXenes, offering valuable insights into their practical applications. Advanced characterization techniques, including X-ray diffraction, microscopy, and electrochemical analysis, are employed to enhance the understanding of MXene structure and electrochemical behavior, particularly in the context of sensing applications. Furthermore, the review addresses the real-world challenges and opportunities associated with integrating MXenes into practical electrochemical sensors, emphasizing the potential of hybrid nanocomposites and the incorporation of MXenes with other nanomaterials. In conclusion, this review serves as a compelling call to action for further research, inspiring the development of enhanced electrochemical sensors with promising implications for the biomedical and environmental fields. [ABSTRACT FROM AUTHOR]