Symposium CH
ABSTRACTS
CH:KL Progress, Challenges, and Opportunities in the Field of MXenes
Y. GOGOTSI, A.J. Drexel Nanomaterials Institute, and Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA
MXenes, discovered in 2011, are no longer new materials. There are approximately 30,000 research papers and dozens of books originating from over 100 countries; about 10,000 patent applications have been filed in the past decade. While that might indicate a mature or saturated research field for many materials, in the case of MXenes, it is just the beginning. We are only starting to explore this emerging field of atomistically designed materials. The number of possible MXene compositions is essentially limitless when considering solid solutions on M and X sites, high-entropy MXenes, and combinations of surface terminations. New subfamilies, including in- and out-of-plane ordered MXenes, oxycarbides, oxynitrides, 2D borides, and silicides, further expand the family of non-oxide 2D ceramic materials based on transition metals. They can be produced through various methods, such as direct synthesis from metal chlorides and carbon sources, or the selective etching of layered ceramics in aqueous etchants, molten salts, or halogen-containing gases. MXenes have opened the door to the world of atomistically designed inorganic materials. In this talk, I will discuss the established and emerging synthesis techniques, key properties, and new potential applications of MXenes.
Session CH-1 Synthesis and structure, morphology and chemistry of MXenes and their composites and hybrids
CH-1:IL01 Synchrotron Radiation Probing MXene-based Energy Materials
LI SONG, National Synchrotron Radiation Laboratory, University of Science and Technology of China Hefei, P. R. China
Two-dimensional layered transition metal carbides/nitrides (MXenes) with ultrathin layered structure and rich elemental variety are emerging as promising energy materials in various research areas including but not limited to energy storage/conversion and photo/electrocatalysis. In fact, the intrinsic property of MXenes is highly tunable by etching process, as well as controlling the surface terminations and interlayer spacing. The high brightness, tunability, and penetrating power of synchrotron radiation light sources with multiple techniques enable to explore numerous intricate properties of MXenes at the nanoscale. Here, I will present resent results on MXene-based energy materials by means of various synchrotron radiation X-ray techniques and methods. Meanwhile, some perspectives will be discussed from the development of other layered energy nanomaterials and synchrotron radiation light sources and integrated techniques for better understanding of energy materials’ structure, composition, and functionality.
CH-1:IL02 Clean and Scalable Micropatterning of MXene Thin Films
B. FAVELUKIS, B. RATZKER, M. SOKOL, Department of Materials Science and Engineering, Tel Aviv University, Ramat, Aviv, Israel
MXenes, a family of two-dimensional transition metal carbides and nitrides, combine excellent electrical conductivity with tunable optical properties, making them promising materials for next-generation microelectronics. However, large-scale device integration is hindered by residual halide salts from synthesis and the absence of reliable submicron patterning techniques. In this work, we introduce two complementary methods that enable clean, high-resolution MXene micropatterning under ambient conditions. The first approach uses a three-step process of spin coating, HCl spin cleaning, and lift-off to produce transparent MXene films approximately 10 nm thick with 1.5 μm lateral resolution, free of crystalline salt residues. The second method employs optimized wet etching with photoresist protection to directly define features as small as 200 nm while maintaining film integrity and controllable undercut. Compared with traditional lift-off, the etched films show improved edge definition, uniformity, and scalability. Functional photodetectors fabricated by both methods exhibit strong photoresponse and stable electrical performance, establishing a reliable pathway for salt-free, high-resolution MXene integration in micro- and nanoelectronic devices.
CH-1:IL03 Novel Methods for the Synthesis of Surface-Modified MXenes
SEON JOON KIM, Korea Institute of Science and Technology, Seoul, South Korea
MXenes, a family of two-dimensional transition metal carbides and nitrides, have attracted significant attention due to their exceptional physicochemical properties and remarkable performance in applications such as EMI shielding, energy storage, and sensing. Also, their densely packed surface functional groups provide unique versatility for tailoring surface chemistry toward diverse applications. In this talk, we introduce tailored surface modification strategies that enable precise control over the interfacial properties of individual MXene sheets. We systematically present novel synthesis approaches based on covalent, coordination, and non-covalent bonding with organic molecules. We first show that molecular grafting facilitates uniform MXene dispersion in organic solvents, while rational design further enables amphiphilic MXenes dispersible in water, polar solvents, and non-polar solvents. We also demonstrate how surface modification can tune and optimize the performance of MXene-based devices, including chemical sensors and EMI shielding. This scalable approach to multifunctional MXene dispersions opens new opportunities for integration into next-generation flexible, wearable, and printed electronic systems.
CH-1:IL04 Chemistry and Reactivity of 2D Transition Metal Carbides/Carbonitrides - MXenes
V.N. MOCHALIN, Department of Chemistry and Department of Materials Science & Engineering, Missouri University of Science & Technology, MO, USA
MXenes raise interest for many applications due to their high electrical conductivity, mechanical properties, potentially tunable electronic structure, nonlinear optical properties, and the ability to be manufactured in the thin film state. However, their chemistry that is key to development of all these applications, still remains poorly understood. Our initial attempts to understand MXene reactivity with oxygen and water brought about surprising results and raised profound questions related to reactivity of 2D materials as compared to their bulk analogues. In particular, our well-established classification of carbides is being challenged by these findings. In this presentation we will also discuss our more recent progress in understanding fundamental MXene chemistry and illustrate how this understanding helps us advance MXene synthesis, suppress unwanted reactions and prolong stability of these materials.
CH-1:IL05 Exploration of New 2D Materials and Their New Properties
HUI-MING CHENG, Institute of Technology for Carbon Neutrality, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
Identification of 2D materials in the monolayer limit has led to discoveries of new phenomena and unusual properties. In this lecture, I first report the growth of large-area high-quality 2D ultrathin Mo2C crystals by CVD, which show 2D characteristics of superconducting transitions that are consistent with Berezinskii–Kosterlitz–Thouless behaviour and show strong dependence of the superconductivity on the crystal thickness. Furthermore, when we introduce elemental silicon during CVD growth of nonlayered molybdenum nitride, we have grown centimeter-scale monolayer films of MoSi2N4 which does not exist in nature and exhibits semiconducting behavior, high strength, and excellent ambient stability. On the other hand, we have found some interesting properties from well-known 2D materials. For example, a class of membranes assembled with 2D transition-metal phosphorus trichalcogenide nanosheets give exceptionally high ion conductivity and superhigh lithium ion conductivity. We demonstrate an anomalously large magneto-birefringence effect in transparent suspension of magnetic 2D crystals, with orders of magnitude larger than that in previously known transparent materials. Finally we have found that strong bulk materials can be densified from their nanosheets at near room temperature.
CH-1:IL07 Defect Engineering for Tailoring the Properties of MXenes
CHONG MIN KOO1, TUFAIL HASSAN1, DOYEON LEE2, JIKWANG CHAE3, MOON-SUNG KIM3, JUNG-MIN OH3, HANJUNG KWON2, 1Sungkyunkwan University, Suwon, Republic of Korea; 2Jeonbuk National University, Republic of Korea; 3INNOMXENE Co., Ltd., Republic of Korea
Defect engineering plays a crucial role in tuning the structural, electrical, and environmental properties of two-dimensional materials. However, precise control over atomic-scale lattice defects in MXenes—such as transition metal and carbon vacancies, oxygen substitution, and lattice strain—remains a fundamental challenge due to the complexity of their multistep top-down synthesis. In this presentation, we introduce a precursor-driven defect engineering strategy that enables controlled manipulation of lattice defects in MXenes. By systematically tuning the MAX synthesis stage using various precursors, we achieve deterministic control over the formation and evolution of titanium vacancies, carbon vacancies, and substitutional oxygen defects throughout the synthesis process. This direct defect control approach leads to predictable modulation of lattice strain and directly influences key material properties, including electrical and thermal conductivity, infrared reflectivity, Joule heating behavior, and electromagnetic shielding performance. Our findings demonstrate that our direct defect engineering strategy offers a practical and effective pathway for tailoring the intrinsic properties of MXenes.
CH-1:IL08 Bioinspired MXene-based Nanocomposites
QUNFENG CHENG, State Key Laboratory of Bioinspired Interfacial Materials Science, School of Nano Science and Technology, Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou, P.R. China
High performance nanocomposites can potentially solve the bottleneck problems of miniaturization and lightweight in the field of aerospace. Although MXenes show excellent mechanical and electrical properties, the properties of MXene-based nanocomposites are much lower than expectation. It was found that the void is an essential factor to decrease the properties of MXene-based nanocomposites, but usually neglected in the past decades. Herein, we applied both focused ion beam and scanning electron microscopy tomography and nanoscale x-ray computed tomography to reconstruct the void microstructure of MXene-based nanocomposites. We further developed a simple and effective densification strategy to cure the voids using a sequential bridging process with different interfacial interactions. The resultant sequentially bridged MXene-based nanocomposites[1-4] achieved dramatical improvement in mechanical properties, resistance to cyclic mechanical deformation, oxidation, and stress relaxation etc.
[1] X. Deng*, and Q. Cheng* et al. Nature 2024, 634, 1103-1110; [2] Q. Cheng* et al. Science 2024, 385, 62-68. (Cover); [3] R.H. Baughman* and Q. Cheng* et al. Science 2024, 383, 771-777; [4] Q. Cheng* et al. Science 2021, 374, 96-99.
CH-1:L09 Unlocking the Potential of MXene – Halide Perovskite Integration Through Building Chemically-Defined Ti3C2Tx-MAPbI3 Interfaces
K. SOBOLEV, I. ZARETSKY, Y. RAKITA, Department of Materials Engineering, Ben Gurion University of the Negev, Beer-Sheva, Israel; Y. RAKITA, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
The integration of Halide Perovskites, HaPs (one of the most superior photovoltaic materials), and MXenes (a fascinating family of highly tunable 2D materials) allows inducing better HaP crystallinity, passivating grain boundaries, mitigating ion migration, and tuning band alignment in a solar cell (SC) heterostructure, thus leading to significant shelf-life and Power Conversion Efficiency (PCE) improvement. Still, the exact chemistry of MXene-HaP mixed system is not well defined, and the boundaries of MXene-induced physiochemical properties turning remain unexplored. Recently we showed how the surface of Ti3C2Tx MXenes can be selectively functionalized with MAI or PbI2 from a HaP-precursor solution, via a selective adsorption onto oxygen termination groups. In this work we show the capability of precisely controlling the chemistry of MXene-HaP interaction through using F- and O-rich Ti3C2Tx MXenes (expected to either weakly or strongly interact with HaP chemical components), and through passivating them with either MAI and PbI2 before integrating into MAPbI3 HaP matrix. We show how the chemistry of the MXene-HaP interface affects the crystallinity, morphology, and optoelectronic properties of HaP thin films, as well as the PCE and shelf-life of the respective SC devices.
CH-1:L10 Raman Signatures of Structural Disorder in Ti3C2 MXenes Derived from Ion-implanted MAX Phases
A.L.A. MARINHO1,2, C. CANAFF1, S. MORISSET1, P. CHARTIER2, N.A GUIGNARD2, M. MARTEAU2, O. HEINTZ3, A. KRYSTIANIAK3, I. LOPEZ-MARIN3, M.-L. DAVID2, V. MAUCHAMP2, S. CÉLÉRIER1, 1Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Poitiers, France; 2Institut Pprime, Université de Poitiers, CNRS, ISAE-ENSMA, Chasseneuil-du-Poitou, France; 3Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR CNRS 6303, Université de Bourgogne Franche-Comté, Dijon, France
MXenes have attracted considerable interest owing to their physico-chemical properties, Ti3C2 being the benchmark system. Despite this promise, their performance Ion implantation offers a controllable route to tailor the defect structure of MXenes, yet the relationship between implantation conditions and defect signatures remains poorly understood. In this presentation, we report a systematic study of Ne2+ implantation in Ti3AlC2 MAX phases, followed by LiF/HCl exfoliation to obtain Ti3C2 MXenes with implantation-driven defects. Raman spectroscopy is employed as the primary tool to probe implantation-induced disorder, owing to its easy accessibility compared to other techniques. Raman results reveal systematic broadening and frequency shifts of characteristic Ti–C vibrational modes as a function of Ne2+ fluence, establishing reliable fingerprints of defect formation. The same behavior is observed by varying HF concentration in exfoliation medium, a well-known method to introduce defects in MXene structures. Complementary analyses by XPS/HAXPES and TEM-EELS confirm the Raman findings, showing preferential loss of Ti, and depth-dependent defect distribution. Together, these results highlight Raman spectroscopy as a robust and non-destructive technique for defect mapping in MXenes.
CH-1:L11 Tailoring the Morphology of MXene/Magnetic Iron Oxide Hybrids for Enhanced Electromagnetic Wave Absorption
YOUN-KYOUNG BAEK1, SEON JOON KIM2, 1Nano Materials Research Division, Korea Institute of Materials Science, Changwon, Korea; 2Extreme Materials Research Center, Korea Institute of Science and Technology, Seoul, Korea
Lightweight, highly conductive MXenes have been widely studied as EM shielding materials. To extend their function from reflection-dominant shielding to broadband absorption, we fabricate MXene-iron oxide magnet hybrids through scalable wet routes. First, hybrid sheets are formed by anchoring APTMS-functionalized iron oxide particles onto aqueous Ti₃C₂Tₓ, modulating excessive permittivity, improving impedance matching and coupling magnetic and dielectric losses. Second, crumpled 3D microspheres are fabricated by spray-drying the dispersion, creating abundant interfaces that promote interfacial polarization and multiple internal reflections. Both designs are expected to significantly enhance multiband absorption compared to pristine MXene, with the crumpled morphology anticipated to amplify loss mechanisms. This work offers a scalable pathway to transform conductive shields into effective EM absorption materials.
This research was financially supported by the Ministry of Trade, Industry, and Energy (MOTIE), Korea, under the “Global Industrial Technology Cooperation Center program” supervised by the Korea Institute for Advancement of Technology (KIAT) (P0028332)
CH-1:IL12 Molten Salt Shielded Synthesis of Carbonitride MXene
SHIBO LI, JIALE YANG, WEIWEI ZHANG, XUEJIN ZHANG, Center of Materials Science and Engineering, School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing, China
Two‐dimensional (2D) carbonitride MXenes have better physical and chemical properties than their carbide MXene counterparts. So far, carbonitride MXenes are mainly synthesized by selective etching of A atomic layers from MAX precursors through HF‐containing solutions and Lewis acid molten salts. However, HF‐containing solutions are not safe because of their corrosiveness and toxicity. Therefore, the Lewis acid molten salt etching has become a relatively popular preparation method to fabricate carbonitride MXenes due to its safer and more environmentally friendly advantages. Despite these advantages of molten salt etching method, vacuum or argon atmosphere is required to protect materials from oxidation during etching. In this work, the molten salt shielded synthesis approach was adopted to fabricate Ti3C1.7N0.3Tx MXene. A mixture of Ti3AlC1.7N0.3 as a precursor and a KCl-CuCl2 salt was put into a muffle furnace in the reaction temperature range of 600-700 °C in air. At high temperatures, the KCl-CuCl2 molten salt acts as both a reduced etching medium and a protective agent against oxidation for MXene. A high purity of Ti3C1.7N0.3Tx was achieved after molten salt etching of Ti3AlC1.7N0.3 at 700 °C for various times in air. The resultant Ti3C1. 7N0.3Tx flakes have -Cl surface terminations, and exhibit a typical accordion-like morphology. The etching mechanism was analyzed. This work expands the synthesis methods of MXenes, and promotes their large-scale preparation and practical applications.
CH-1:IL13 Exploring MXenes
P.O.Å. PERSSON, Materials Microscopy, Thin Film Physics Division, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden; and Wallenberg Initiative Materials Science for Sustainability, Department of Science and Technology, Linköping University, Norrköping, Sweden
MXenes stands out as the first 2D material that has been chemically exfoliated. MXenes are typically produced from the parent family of MAX phases, which are nanolaminated phases of carbides and/or nitrides that follow the general formula Mn+1AXn (n = 1, 2 or 3), where M is an early transition metal, A is a group A element, and X is either C and/ or N. When the MAX phase is chemically etched, the A layers are removed, and the freshly exposed M-element surfaces are instantly terminated by species (surface terminations) that are native to the etchant. MXenes are therefore best described by the formula Mn+1XnTz, where Tz are the surface terminations. MXene’s 2D nature, outstanding conductivity, and hydrophilicity combined with a range of elemental and structural configurations and a wide variety of surface terminations, render them highly attractive for a wide variety of applications, e.g. energy storage, EMI shielding, catalysis, filtering etc. Due to its generic structure, most research efforts are directed at exploring new MXenes or applications, and less focus is spent on exploring the core structure and the terminations in detail. Using high resolution STEM-EELS and ETEM-EELS, I will discuss recent findings and developments in exploring the fundamental structure of MXene.
CH-1:L14 An Energy-Efficient Route to Compositionally Tunable Nb-Based MXenes
S.V. MELKONYAN1,2, L.E. MINASYAN1, A.H. BHALLI3, R. IVANOV3, A.S. SHAMSHIRGAR4, F. CHABANAIS4, P.O. PERSSON4, I. HUSSAINOVA3, J. ROSEN4, S.V. AYDINYAN1,3, 1Laboratory of Macrokinetics of Solid State Reactions, Institute of Chemical Physics NAS of Armenia, Yerevan, Armenia; 2Faculty of Chemistry, Yerevan State University, Yerevan, Armenia; 3Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Tallinn, Estonia; 4Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden
Nb-based MXenes hold great promise for high-performance energy storage and catalytic applications; however, their scalable synthesis is limited by energy-intensive precursor preparation and harsh etching conditions. In this study, an energy-efficient approach for producing Nb-based MXenes was developed from Nb₂AlC and (Nb,Mo)₂AlC MAX phase precursors derived from chemically activated self-propagating high-temperature synthesis (SHS). The activated combustion generates refined microstructures, increased defect density, and enhanced chemical reactivity, collectively enabling faster and milder etching of Al layers. The resulting Nb₂CTₓ and (Nb,Mo)₂CTₓ MXenes exhibit higher yield, improved flake morphology, and uniform delamination compared to conventionally sintered analogues. Structural, microstructural, and electrochemical characterization confirm high crystallinity, homogeneous element distribution, and promising electrochemical performance, demonstrating that kinetically activated SHS is an effective route for scalable, tunable, and high-quality Nb-based MXene synthesis.
CH-1:L15 Study of Near Room-temperature Crack-healing of MXene Nanocomposites Fabricated by Cold Sintering Process
SON THANH NGUYEN1, AYAHISA OKAWA2, THI MAI DUNG DO3, YEONGJUN SEO4, TSUYOSHI TAKAHASHI1, KAZUNORI ISHITSUKA1, HISAYUKI SUEMATSU3, TADACHIKA NAKAYAMA3, 1National Institute of Technology, Kushiro College, Japan; 2Tohoku University, Japan; 3Nagaoka University of Technology, Japan; 4The University of Osaka, Japan
Surface cracks can lead to severe damages of ceramic materials. Self-healing ability has been studied to enables crack-repair at high temperatures (700°C ) by adding healing agents to utilize their volumetric expansion under oxidation to seal the crack. To expand the avalilabily of crack healing by reducing their healing temperature, in this research, we synthesized two types of MXene (Ti3C2 and TiNbC) and fabricated their ceramic matrix composites (CMCs) with ZnO. Currently, the research on the sintering MXene/CMCs is still facing challenges. MXene undergoes a phase transition at around 800°C, thus conventional high-temperature processes like hot-pressing are not optimal for fabricating MXene composite materials. Here, we focused on using cold sintering process (CSP) which enables to sinter at temperatures below 300°C, to fabricate the CMCs. Then, the fabricated composite materials with high density were investigated their crack-healing ability at near room-temperature (100-300 °C). The results exhibit that the surface crack on the both MXene/CMCs can be self-healed after heat-treatment at the above temperature range, although the healing effeciency between them is slightly different. This result may pave a way for the development of new self-healing ceramic materials.
CH-1:L16 Inserting Nitrogen in Ti3C2Tz : TEM-EELS Characterizations of Plasma Nitrided MXene Sheets
N. CONDE, M.-L. DAVID, L. PICHON, V. MAUCHAMP, M. DROUET, University of Poitiers, ISAE-ENSMA, CNRS, PPRIME, Poitiers, France; S. CELERIER, S. MORISSET, University of Poitiers, CNRS, IC2MP, Poitiers, France
Inserting nitrogen into MXene carbides is an important challenge as carbo-nitrides exhibit better properties for a large range of application. In this work we showcase the structural and chemical modifications induced in plasma nitrided Ti3C2Tz multilayers. Different treatment parameters were investigated (reactive atmosphere composition (N2 + H2), duration, temperature) and their structural and chemical impact are characterized using TEM-EELS. After 1 h at 300°C in a 1 Pa (60%vol. N2 + 40%vol. H2) low pressure reactive atmosphere excited by 700 W RF (13,56 MHz) plasma, the Ti3C2Tz multilayers are nitrided. The N/Ti ratio determined on multilayers of different thicknesses (3-60 nm) shows a dependency as a function of the multilayers thickness, suggesting that mainly the surface of the MXene sheets is modified. This is confirmed by the detailed analysis of the C K-edge fine structure clearly showing that a TiC1-xNx phase is created over the first 1.5-2.5 nm while the underneath layers are barely modified. The nitrided MXene sheets are barely evolving by using treatments with longer durations (24 h), higher temperatures (500°C), or by removing H2 from the plasma. These results highlight plasma nitriding as a robust approach for the surface engineering of Ti3C2Tz multilayers.
CH-1:IL17 An Expanded Toolbox for MXenes: Integrating Theoretical and Experimental Perspectives
J. ROSEN, Linköping University, Linköping, Sweden
About 15 years after the discovery of MXenes, research on their synthesis, characterization, and potential applications continues to expand. This growing family of two-dimensional (2D) carbides and nitrides now includes materials with one or more transition metals arranged in chemically ordered or disordered structures of three, five, seven, or nine atomic layers, and with surface chemistries defined by various terminations. By combining different metal (M) and nonmetal (X) elements with diverse surface terminations, an almost limitless number of MXene compositions appears possible. However, designing structures and compositions beyond current MXenes requires an expanded toolbox, both for predictive and validating modeling, and for developing scalable, sustainable synthesis techniques. This talk will present a forward-looking perspective on atomic-scale design and synthesis of MXenes and their parent materials. Approaches for identifying synthesizable MXenes and experimental methods not previously applied to MXene synthesis will be presented and discussed. Finally, important research directions will be outlined, focusing on the role of MXenes in emerging applications.
CH-1:IL18 High-Performance MXene Composite Fibers and their Applications in Wearable Textiles
TIANZHU ZHOU, State Key Laboratory of Bioinspired Interfacial Materials Science, School of Nano Science and Technology, University of Science and Technology of China (USTC), Suzhou, China
Two-dimensional nanomaterials (MXene), owing to their excellent mechanical and electrical properties, offer great potential for constructing macroscopic fibers with applications in wearable textiles and related fields. However, structural defects and weak interlayer interactions make it difficult to simultaneously achieve high mechanical strength and high electrical conductivity in these fibers, and continuous fabrication remains a challenge. To overcome these bottlenecks, this study proposes a continuous and controllable-scale fabrication strategy, leveraging the synergistic effects of interfacial interactions and thermal drawing stress to successfully produce macroscopic MXene fibers. These fibers exhibit outstanding tensile strength, ultrahigh toughness, and excellent electrical conductivity. Based on this, large-area wearable textiles fabricated from these fibers not only demonstrate intelligent functionalities, but also possess long-term durability and stability. This work provides an effective route for the scalable application of high-performance MXene fibers and offers important theoretical guidance and technical support for the industrial fabrication of other advanced functional fibers.
CH-1:IL19 Synthesis and Structure of Electrically Conductive and Wear-resistant at High Temperatures Ti, Nb, Cr, Mo - Al, Sn - C MAX-phases-based Bulks and Coatings
T. PRIKHNA1,6, A. KUPRIN2, V. SVERDUN1, V. PODHURSKA3, M. KARPETS1,4, O. OSTASH3, S. PONOMARYOV5, P. POTAPOV6, D. POHL7, T. SERBENYUK1, 1Institute for Superhard Materials of the National Academy of Sciences of Ukraine, Kiev, Ukraine; 2National Science Center Kharkov Institute of Physics and Technology, Kharkov, Ukraine; 3Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Ukraine; 4National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine; 5Institute of Semiconductor Physics of the National Academy of Sciences of Ukraine (NASU), Kyiv, Ukraine; 6Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany; 7Dresden Center for Nanoanalysis (DCN), TU Dresden, Barkhausenbau, Dresden, Saxony, Germany
MAX-phases bulks and coatings are promising materials for various industrial application due to combination of high electrical and thermal conductivities, high chemical stability at high temperatures in different aggressive environments, the ability to simultaneously provide high were resistance and low friction, etc. The presentation will consider the manufacturing features, structural characterization using X-ray, SEM, TEM, and Auger spectroscopy, as well as the study of the physicochemical and mechanical properties of bulk MAX phases (obtained from powders of TiC, TiH2, Al, and C without and with additions of Nb, Cr, Mo, and Sn) by hot pressing for application as electric transport pantographs, electrical contacts, or targets for deposition of coatings. The peculiarities of deposition of electroconductive and wear-resistant coatings (operating at 500-600 oC) by hybrid magnetron sputtering, and arc-vacuum technology using the developed hot-pressed MAX phases targets will be discussed. The results of studies of the structure and properties of the deposited coatings for interconnects of solid-state oxygen fuel cells (SOFC) and light molten carbonate fuel cells (MCF), as well as for manufacturing of sliding contacts operating in fretting corrosion mode at 500 °C will be presented.
CH-1:IL20 2D Materials from Selective Etching, Beyond MXene
JIE ZHOU, J. ROSEN, Materials Design Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden
Selective etching, originally developed for producing MXenes from MAX phases, has served as an emerging approach for synthesizing novel two-dimensional (2D) materials from non-van der Waals solids. Our work has extended this concept beyond carbides and nitrides to borides and intermetallics. Inspired by theoretical predictions of in-plane (i-MAB) and out-of-plane (o-MAB) ordered borides, we experimentally demonstrated that such laminated borides could serve as effective templates for chemical exfoliation. Selective removal of Al and Y from the quaternary boride Mo4/3Y2/3AlB₂ (i-MAB) yielded the first 2D transition-metal boride, boridene (Mo4/3B2-xTz), establishing a boron-based analogue to MXenes. Extending this approach, etching of Ti₄MoSiB₂ in molten ZnCl₂ produced 2D TiOxCly, showing that o-MAB phases can act as non-MAX precursors for 2D derivatives. Guided by the predictive high-throughput framework for identifying exfoliable ternary compounds under acidic conditions, we further achieved selective removal of Y from YRu₂Si₂, forming delaminated Ru₂SixOy sheets with catalytic activity. Together, these results establish selective etching as a route to 2D materials beyond MXenes, encompassing borides and intermetallics—including silicides—with potential for sustainable energy applications.
CH-1:L21 Atomic Layer Etching for MXene Soft Robotics
HAOZHE "HARRY" WANG, Duke University, Durham, NC, USA
Two-dimensional transition metal carbide Ti3C2Tx (MXene) exhibits exceptional electrical conductivity and photothermal properties but suffers from performance limitations due to fluorine surface terminations from conventional synthesis. We report a plasma-enabled atomic layer etching approach that transforms surface chemistry from fluorine- to oxygen-dominated terminations, achieving an 80% enhancement in electrical conductivity and improved photothermal conversion efficiency. The surface-modified MXene, when integrated with cellulose nanofibrils, creates high-performance composite actuators that demonstrate superior bending actuation and force generation under near-infrared illumination. The plasma treatment approach offers manufacturing versatility, enabling fabrication through various methods including solution casting, 3D printing, and layer-by-layer assembly. These enhanced actuators operate effectively across multiple length scales, from millimeter-scale microrobotic devices to centimeter-scale systems, demonstrating significant potential for diverse soft robotics applications including precision manipulation, biomimetic systems, and wearable technologies. This surface engineering strategy provides a scalable pathway for optimizing MXene materials in next-generation soft robotics.
CH-1:L21b Fermi Surface Topology and Anisotropic Band Structure of Oxygen-Terminated Ti3C2Tx MXene
M. MAGNUSON, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden
Understanding and tailoring the electronic properties of MXenes requires detailed knowledge of their Fermi surface and band structure. This study investigates the fermiology of Ti3C2Tx MXene with pure oxygen termination (Ti3C2O2), revealing its electronic band topology and orbital characteristics. Epitaxial thin films were synthesized via magnetron sputtering and3 selectively etched to achieve oxygen-only termination. Surface order and composition were verified using LEED and XPS, and synchrotron-based angle-resolved photoemission spectroscopy (ARPES) was used to map the band structure and Fermi surface across the Brillouin zone. The results show a metallic, anisotropic 2D electronic structure with highly dispersive Ti 3d-derived bands near the Fermi level. Conical band crossings, reminiscent of Dirac points, appear at ~1.5 eV below the Fermi energy. The Fermi surface shows sixfold symmetry with hexagonal warping, indicating in-plane hole-like conduction and out-of-plane electron-like states. Polarization-dependent ARPES distinguishes orbital contributions from surface oxygen. These findings show that despite oxygen termination, which typically induces semiconducting behavior, Ti3C2Tx remains metallic due to orbital hybridization. This fermiological description opens pathways for band engineering in MXenes, with implications for transparent conductors, energy storage, and catalysis.
Fermiology and band structure of oxygen-terminated Ti3C2Tx MXene; Martin Magnuson, Per Eklund, and Craig Polley; Phys. Rev. Lett. 134 106201 (2025). DOI: https://doi.org/10.1103/PhysRevLett.134.106201
Session CH-2 Property characterization
CH-2:L22 Tunable Properties of Carbonitride Ti3C2-yNyTx MXene with Varying N Contents
WEIWEI ZHANG, SHIBO LI, XUEJIN ZHANG, Center of Materials Science and Engineering, School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing, China
Ti3C2-yNyTx (0
CH-2:L23 Ferromagnetism at Room Temperature in the MAX Phase (Mn,Cr)2GaC
E.B. THORSTEINSSON1, M. DAHLQVIST2, A. ELSUKOVA2, A. PETRUHINS2, P.O.Å. PERSSON2, J. ROSEN2, D.D. KHALYAVIN3, P. MANUEL3, A.S. INGASON4, F. MAGNUS1, 1Science Institute, University of Iceland, Reykjavik, Iceland; 2Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden; 3ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot, UK; 4Grein Research ehf., Reykjavik, Iceland
The interest in low-dimensional magnetism has prompted the search for new MAX phases with magnetic ordering. The nanolaminated structure gives rise to competing interactions within and across layers, resulting in complex magnetic ordering. Until now, no MAX phase has exhibited ferromagnetism with a significant remanent moment at room temperature, limiting their use in applications. Here we explore partial substitution of Mn by Cr on the M site of Mn2GaC in order to control the magnetic ordering. These substitutions are guided by spin-dependent density functional theory calculations which predict phase stability and magnetic ordering. The MAX phases are grown as thin films by co-sputtering from elemental sources, which allows us to tune the stoichiometry precisely. We find that substituting Mn by small amounts of Cr stabilizes ferromagnetic ordering at room temperature. The MAX phase (Mn1-xCrx)2GaC, with x in the range 0.06–0.29, is strongly ferromagnetic with an ordering temperature of up to 489 K. We examine the nature of the magnetic ordering using neutron diffraction measurements. The results reveal how the delicate balance between ferro- and antiferromagnetism can be tuned in MAX phases, with potential applications ranging from bulk magnets to antiferromagnetic spintronics.
CH-2:L24 2D versus 3D-Like Electrical Behavior of MXene Thin Films: Insights from Weak Localization in the Role of Thickness, Interflake Coupling and Defects
S. TANGUI1, S. HURAND1, S. CÉLÉRIER2, A. BENMOUMEN1,3, P. MOREAU3, M.-L. DAVID1, V. MAUCHAMP1, 1Université de Poitiers, ISAE-ENSMA, CNRS, PPRIME, Poitiers, France; 2Université de Poitiers, CNRS, IC2MP, Poitiers, France; 3Nantes Université, CNRS, IMN, Nantes, France
MXenes stand out from other 2D materials because they combine very good electrical conductivity with hydrophilicity, easing processing as thin films. Thus, there is a high fundamental interest in unraveling the electronic transport mechanisms at stake in multilayers of the most conducting MXene, Ti3C2Tx. Although weak localization (WL) has been proposed as the dominating low-temperature (LT) transport mechanism in Ti3C2Tx thin films, there have been few attempts to model it quantitatively. In this work, the role of important structural parameters – thickness, interflake coupling, defects – on the dimensionality of the LT transport mechanisms in spin-coated Ti3C2Tx thin films is investigated through LT and magnetic field dependent resistivity measurements. A dimensional crossover from 2D to 3D WL is clearly evidenced when the film thickness exceeds the dephasing length lϕ, estimated here in the 50–100 nm range. 2D WL can be restored by weakening the coupling between adjacent flakes, the intrinsic thickness of which is lower than lϕ, hence acting as parallel 2D conductors. Alternatively, lϕ can be reduced down to the 10 nm range by defects. These results emphasize the ability of WL quantitative study to give deep insights in the physics of electron transport in MXene thin films.
CH-2:IL25 High-resolution Structural Colors and Infrared Identification with MXenes
MEIKANG HAN, Fudan University, Shanghai, China
MXenes have shown various electromagnetic functions across the broad electromagnetic spectrum, due to their tunable surface chemistry, anisotropic electronic conducting, and atom-scale layers. In particular, MXenes offer chemically controlled optical and electronic properties that facilitate new ways of influencing material interactions with electromagnetic waves over UV-vis, infrared, terahertz, and gigahertz ranges. Combining these features with ease in processing and excellent mechanical properties, MXenes have already shown great promise in electromagnetic applications such as electromagnetic interference shielding, photothermal conversion, thermal management, and wireless communication. Here we show the fundamental interactions of MXene with visible light and infrared. We demonstrated that structural colors and infrared radiation can be precisely manipulated by MXene compositions and layer structures. High-resolution structural colors and infrared identification patterns were achieved with different coating methods. The versatility of MXenes at optical and infrared wavelengths provides a platform for developing MXene-based smart, flexible devices and wearables capable of multispectral camouflage, thermal management and imaging.
CH-2:IL26 Structural Anisotropy and Phonon Properties of Halogen-Terminated Ti3C2 MXenes
H. PAZNIAK, M. RIABOV, T. OUISSE, UGA, CNRS, Grenoble INP, LMGP, Grenoble Cedex, France; A. CHAMPAGNE, ICMCB, CNRS, Pessac Cedex, Bordeaux, France, F. WILHELM, ESRF, Grenoble, France; U. WIEDWALD, University of Duisburg-Essen, Duisburg, Germany
High-quality Ti3C2 MXenes with –Cl and –Br surface terminations were synthesized via a Lewis acid molten-salt approach. The resulting materials exhibited high crystallinity and uniform surface functionalization, enabling reliable structural and property analyses. To probe their anisotropic features, X-ray linear dichroism (XLD) measurements were performed, revealing that the Ti pre-edge signal depends on the nature of the surface termination, whereas the halogen K-edge signal is sensitive to the van der Waals stacking configuration. Building on this structural insight, high-resolution, polarization-dependent Raman spectroscopy combined with density functional perturbation theory (DFPT) calculations confirmed the anisotropic vibrational response and enabled an unambiguous assignment of phonon mode symmetries. Furthermore, temperature-dependent Raman measurements evidenced pronounced anharmonic effects and confirmed the thermal stability of the halogen-terminated MXenes. Complementary specific heat analyses revealed clear signatures of the two-dimensional character of Ti3C2 at low temperatures and provided additional insight into its thermal behavior and acoustic phonon modes.
CH-2:L26b Surface Functionalized MXene/Epoxy Composites for Enhanced Mechanical Robustness, Thermal Transport, and EMI Shielding Performance
S.M. NAQVI1 CHONG MIN KOO1,2, 1School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon-si, Gyeonggi-do, Republic of Korea; 2School of Chemical Engineering, Sungkyunkwan University, Suwon-si, Gyeonggi-do, Republic of Korea
MXenes have gained significant attention as multifunctional fillers in MXene-polymer nanocomposites. However, their inherently hydrophilic surfaces pose challenges in compatibility with hydrophobic polymers such as epoxy, potentially limiting composite performance. In this study, high-crystalline Ti3C2Tx MXenes were functionalized with alkylated 3,4-dihydroxy-l-phenylalanine ligands, transforming the hydrophilic MXene flakes into a more hydrophobic form, thus significantly enhancing compatibility with the epoxy matrix. This surface functionalization enabled uniform dispersion and supported the formation of a percolation network within the epoxy matrix at a low filler loading of just 0.12 vol %. Consequently, the functionalized MXene-epoxy nanocomposites exhibited remarkable performance, including an electrical conductivity of 8200 S m–1, outstanding electromagnetic interference (EMI) shielding effectiveness (SE) of 100 dB at 110 GHz (61 dB at 8.2 GHz), improved thermal conductivity of 1.37 W m–1 K–1, and a 300% increase in tensile toughness (271 KJ m–3). These properties substantially outperformed those of their nonfunctionalized counterparts and surpassed previously reported MXene-polymer nanocomposites. This study underscores the critical role of surface functionalization in unlocking the full potential of two-dimensional (2D) MXenes in polymer composites, providing a pathway to advanced multifunctional nanocomposite materials.
Session CH-3 Applications
CH-3:IL27 Tubular MXenes Synthesized from Carbon Fibers Toward Energy Applications
F.M. OLIVEIRA, Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology Prague, Prague, Czech Republic
MXenes, a prominent class of two-dimensional (2D) transition metal carbides and nitrides, exhibit outstanding electrical conductivity, surface activity, and chemical tunability, making them highly attractive for applications where rapid ion and charge transport are critical. Their performance is closely tied to structure and morphology, emphasising the need for controlled synthesis strategies. This work presents a versatile approach for producing tubular MXenes by employing carbon fibres as both a carbon source and a structural template. The process enables the formation of tubular MAX phase precursors that retain their hollow architecture after selective transformation into MXenes, and can be achieved via either a solid-state or a molten-salt route. Advanced structural, morphological, and surface analyses support findings into the preservation of the tubular framework and the oriented stacking of MXene layers, highlighting their potential for enhanced ion and charge transport. This approach is adaptable to different MAX chemistries, enabling morphology control for applications in electromagnetic shielding, catalysis, sensing, and energy storage.
CH-3:IL28 Understanding the Role of MXenes in Beyond Conventional Catalysts for the Oxygen Evolution Reaction
M.P. BROWNE, Helmholtz Young Investigator Group Electrocatalysis: Synthesis to Devices, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
In the Electrocatalysis Synthesis to Devices Group at Helmholtz-Zentrum Berlin, our research is focused on combining MXenes, Figure 1, and water splitting active materials to create the next generation Oxygen Evolution Reaction (OER) catalysts. Metal oxides, e.g. Ni oxides, are known to be the most active materials for the OER in alkaline media but lack high conductivity and exhibit only average OER overpotentials. On the other hand, MXenes are highly conductive but oxidise readily under several conditions due to its termination sites and don’t contain OER active sites.1,2 To overcome these issues, we employ several strategies in our group to combine these two materials to make one material which is OER active and highly conductive. Furthermore, by blocking the MXene termination sites with metal-based materials, this may lead to less oxidation of the MXenes structure. This presentation will focus on the development of hybrid MXene materials for the OER through various fabrication methods to produce Green H2.3-6
1. npj 2D Materials and Applications, 7, 1 (2023); 2. Current Opinion in Electrochemistry, 34, 101021 (2022); 3. Electrochimica Acta, 490, 144269 (2024); 4. ChemElectroChem, e202400656 (2025); 5. Journal of Materials Chemistry A, 12, 24248-24259 (2024); 6. Advanced Functional Materials, 2503842 (2025).
CH-3:IL29 High-performance Two-Dimensional Nanocomposites
SIJIE WAN, Beihang University, Beijing, P.R. China
Here we demonstrate the visual evidence of the voids in 2D nanocomposites by reconstructing their microstructure using nano-CT and FIB-SEM. Considering that voids are mainly caused by the capillary contraction and thereby wrinkling of nanosheets during solvent evaporation, various strategies have been proposed to decrease voids by restricting the capillary contraction of nanosheets and freezing their alignment, including interfacial bridging, intercalating nanomaterials, and confined assembly. Moreover, a scalable fabrication technology of 2D nanocomposites has been developed by roll-to-roll-assisted blade coating integrated with sequential bridging. The resultant 2D nanocomposites present excellent mechanical and electrical properties and superior osteogenesis performance. More specifically, their tensile strength, toughness, and electrical conductivity surpass those of commercial carbon fiber fabric composites, while the osteogenesis efficiency far exceeds that of commercial guided bone regeneration membranes, establishing marked potential for using in the fields of aerospace and clinical bone repair.
CH-3:IL30 Application of MXenes for Thermal Catalysis and Electrocatalysis
A.L. ALVARENGA MARINHO, V. FOGIEL, N. BENBAKOURA, C. CROISE, L. LOUPIAS, C. MORAIS, S. MORISSET, C. CANAFF, N. GUIGNARD, X. COURTOIS, V. MAUCHAMP, F. CAN, A. HABRIOUX, S. CELERIER, IC2MP and Pprime Institute, Poitiers, France
MXenes, a family of two-dimensional transition metal carbonitrides, have emerged as highly promising materials for catalytic and electrocatalytic applications. Their unique structural features - large surface area, tunable surface terminations and core composition, and high electrical conductivity - provide versatile active sites and facilitate efficient charge transfer. These properties allow MXenes to serve as effective catalysts or catalyst supports in a wide range of reactions, including hydrogen and oxygen evolution (electrocatalysis) as well as NH₃ synthesis and CO₂ valorization (thermal catalysis), among many others. Moreover, their surface chemistry can be tailored to enhance activity, stability, and selectivity, making them competitive alternatives to conventional noble metal-based catalysts. This presentation will highlight selected examples of research conducted at IC2MP on catalysis and electrocatalysis using MXene-based catalysts, both pristine and composite. The focus will be on understanding how composition, synthesis conditions, and defects influence the catalytic performance of these materials. These insights aims to provide a foundation for the rational development of MXene-based catalysts with optimized performance for a wide range of catalytic applications.
CH-3:IL31 Applications of MXenes in Energy Storage
BIN XU, Yan'an University, Beijing University of Chemical Technology, China
MXenes exhibit significant potential for electrochemical energy storage applications, including supercapacitors, lithium/sodium/potassium-ion batteries, lithium-sulfur batteries, and aqueous batteries, due to their metallic conductivity, abundant surface terminations, and excellent mechanical properties. To mitigate the issue of restacking in two-dimensional MXene nanosheets, three-dimensional architectures are constructed using various strategies like in-situ template method, electrostatic induction method, etc., which significantly enhance their capacity and rate capability. By leveraging the unique layered structure and high conductivity of MXenes, active materials such as metal oxides and sulfides are assembled onto MXene substances to fabricate composite electrode materials with high capacity and superior cycling stability. The MXenes with chemisorption capabilities and catalytic activity are developed to act as sulfur hosts or separated modification layers, thereby improving the electrochemical performance of lithium-sulfur and sodium-sulfur batteries. Additionally, MXenes are used for facilitating uniform and reversible zinc stripping/plating, thus enhancing the stability and reversibility of zinc anodes in aqueous systems. A novel electrode fabrication method utilizing MXene nanosheets as a multifunctional conductive binder is proposed, resulting in flexible electrodes that outperform conventional counterparts in electrochemical performance.
CH-3:IL32 2D Materials, MXenes: High Dimensional Immune Approaches Toward Biomedical Applications
L.G. DELOGU1,2, R. CAGLIANI1, M. KHALED HASAN AHMED ALHOSANI1, O. HAZEM ELKHATIB1, L. FUSCO2, L. GIRO2, B. CHACON3, Y. GOGOTSI3, 1Department of Biological Sciences, Khalifa University of Science & Technology, Abu Dhabi, United Arab Emirates; 2Department of Biomedical Science, University of Padua, Padua, Italy; 3Department of Materials Science and Engineering and A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA, USA
Thanks to their unique physicochemical properties, two-dimensional (2D) nanomaterials have attracted increasing interest for a wide variety of applications in several fields, including nanotechnology, energy technology, and biomedicine. We recently depicted the “NanoImmunity-by-Design” concept, where the characterization of two-dimensional (2D) materials is not solely based on their physical-chemical parameters but also on their immune profiling. The immune profiling can only be revealed in its complexity by applying unique and informative high-dimensional approaches. Therefore, we exploited high-dimensional approaches, such as single-cell mass cytometry (CyTOF) and imaging mass cytometry on graphene and other novel 2D materials, such as transition metal carbides/carbonitrides (MXenes). We revealed that the amino-functionalization of graphene oxide increased its immunocompatibility. Moreover, we combined graphene with AgInS2 nanocrystals, enabling its detection by CyTOF on a large variety of primary immune cells. Recently, we reported the immune modulation of specific MXenes, and their label-free detection by CyTOF and high-dimensional imaging approaches by our LINKED approach. We translated our LINKED approach in the context of environmental nanopollutants, nanoplastics. Together with our more recently published works, unpublished results will be presented on a wider variety of novel 2D materials, including MXenes, transition metal dichalcogenides (MoS2 and WS2), and bismuthene. Our results conceptualize that the chemical and immunological design of 2D materials offers new strategies for their safe exploitation in biomedicine.
CH-3:IL33 Titanium Carbide MXene for Single Molecule Biosensing
L. MANZANARES, IEMN and Centrale Lille Institut, Villeneuve d'Ascq, France
Single-molecule detection delivers valuable information in bioanalysis by observing individual molecular events. Fluorescence energy transfer methods such as FRET probe distances of 3–10 nm between donor and acceptor dyes, yet quantifying those distances can be difficult. Graphene-based energy transfer broadens this range to 10-40 nm but is limited by graphene’s hydrophobicity and layer-dependent lifetime effects, reducing reproducibility and biocompatibility. We evaluated Ti₃C₂Tₓ MXene in this context. We studied MXene-DNA interfaces with fluorescence spectroscopy and molecular dynamics. In real-time DNA hybridization on MXene, fluorescence rose as strands paired, while simulations confirmed fluorophore-surface distances changed by under 0.3 nm, suggesting sub-nanometer sensitivity and higher compatibility than graphene-based materials (10.1039/C9SC03049B). Using single-molecule imaging and DNA nanostructures to position dyes 1–8 nm above MXene-coated glass, we observed strong quenching up to 8 nm, a property nearly insensitive to MXene thickness, thus, robust. Applied to 5 nm supported lipid bilayers, MXenes enabled single-molecule, leaflet-specific sensing in biomembrane models (10.1002/adma.202411724), a promising application in biophysics and pharmaceutical science.
CH-3:L34 Surface-Engineered MXenes for Catalytic PET Upcycling
I.M. CHIRICA, S. NEAȚU, A. MIREA, F. NEAȚU, National Institute of Materials Physics, Magurele, Romania; M.W. BARSOUM, Department of Materials Science and Engineering, Drexel University, Philadelphia, USA; M. FLOREA, University of Bucharest, ISDS, Romania
One of the most pressing environmental challenges today concerns the growing impact of plastic waste, particularly from polymer recycling, which has cast doubt on the sustainability of materials that otherwise play a vital role in our everyday lives. Heterogeneous catalysis is a key strategy for the chemical recycling of waste plastics; however, despite significant effort, no catalytic system has yet demonstrated sufficiently high efficiency to enable a viable industrial process. In this context, the goal of this study is to develop new solid acid catalysts capable of depolymerizing PET back into its raw constituents. A promising strategy to tune the catalytic performance of MXenes is through surface chemistry engineering. Therefore, in this work, we propose to enhance the acidity of MXenes by introducing –SO₃H functional groups, aiming to obtain sulfonated MXenes (–SO₃H–MXene) capable of depolymerizing polyethylene terephthalate (PET) via the hydrolysis pathway. In this way, using the sulfonated MXene catalysts, we achieved complete PET conversion with a 75% yield of terephthalic acid as the sole reaction product. Optimization of key parameters (temperature, pressure, catalyst loading) confirmed that MXene -SO₃H is a highly promising candidate for efficient PET upcycling.
Session CH-4 Theory, computational modelling, data science and new directions for MXenes
CH-4:IL35 Defect Engineering in MXenes using Ion and Electron Beams
A. BENMOUMEN1,2, M.-L. DAVID1, E. GAUTRON2, A.L. MARINHO1,3, L. PIZZAGALLI1, T. BEQUET1, T. MARTINEZ1, S. CÉLÉRIER1, S. TANGUI1, S. HURAND1, P. MOREAU2, V. MAUCHAMP1, 1Université de Poitiers, CNRS, ISAE-ENSMA, PPRIME, Poitiers, France; 2Nantes Université, CNRS, Institut des Matériaux de Nantes Jean Rouxel, IMN, Nantes, France; 3Université de Poitiers, CNRS, IC2MP, Poitiers, France
MXenes are well known for their very large structural and chemical diversity, opening many avenues for properties tuning. Such diversity is mainly achieved through the exfoliation of different precursors or using post-synthesis treatments. On the other hand, ion irradiation (IIr), ion implantation (IIm) or electron beam irradiation have proven their relevance for the deep and controllable modifications of 2D materials properties. These approaches are however still largely unexplored in the MXenes community. In this presentation, the use of ion and electron beams to perform defect engineering and modify the physical properties of MXene multilayers will be presented, mainly focusing on the benchmark Ti3C2Tz system. Among other points, the benefits of IIr and IIm for selective optical properties modifications and charge carrier density tuning will be discussed. Results will be rationalized on the basis of transmission electron microscopy (TEM) characterizations coupled to ab initio simulations. As an alternative approach, in situ electron irradiation performed in a TEM will be shown to allow for the fine tuning of Ti3C2Tz layers chemistry on the nanometer scale. In particular, we will evidence the possibility to create nitrogen-rich nanodomains in nitrogen-doped layers.
CH-4:IL36 No Time for Disorder: The Quest for Stable and Synthesizable Super-ordered MAX Phases (s-MAX)
M. DAHLQVIST, Materials Design Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden
Realizing super-order in MAX phases, where both in-plane and out-of-plane chemical ordering of metal atoms coexist, remains a major challenge due to the large compositional complexity and configurational entropy of mixing among three metallic elements in combination with A-group (Al, Ga) and carbon layers. Using density functional theory (DFT), we investigate the thermodynamic stability of Al- and Ga-based super-ordered MAX (s-MAX) phases and show that rare-earth-containing s-MAX (Y, Er, Lu) exhibit comparable energetics, allowing Y to serve as a representative for the rare-earth elements. We demonstrate how atomic size mismatches, distinct chemical ordering motifs, and controlled intermixing between the metallic elements collectively determine phase stability. s-MAX phases are stabilized by cooperative in-plane ordering of small and large atoms, like i-MAX phases, providing a characteristic lattice distortion that reduces strain and lowers energy. I will discuss design principles for achieving super-order in MAX phases and beyond, highlighting the delicate balance between chemical order and entropy-driven mixing in ideal and off-stoichiometric compositions. Insights providing a foundation for discovering and synthesizing next-generation complex MAX phases and MXene derivatives.
CH-4:IL37 Mechanism of MXene Nanochannels Mediating Humidity-Activated Ion Transport
YANLEI WANG, School of Chemistry and Life Resources, Renmin University of China, Beijing, China
Moisture-driven power generation is recognized as a truly clean energy technology, with the key challenge lying in the design of porous functional materials. MXene, with its tunable surface chemistry, high electrical conductivity, and two-dimensional structure, has emerged as a game-changing material in this field. This presentation will focus on the application of MXene in moisture-enabled electricity generation, addressing the following aspects: (1) The role of surface functional groups of MXene in governing molecular-level interactions with other fluidic molecules; (2) Selective ion transport mechanisms within MXene nanochannels under varying humidity conditions; (3) Strategies for enhancing the power generation performance of MXene-based moisture-driven energy harvesters. The related research not only deepens the fundamental understanding of surface modulation in MXene materials but also extends their applications, thereby advancing the development of sustainable power generation technologies.
CH-4:L38 Olefin Production by Alcohol Dehydration on MXenes
A.B. RODRÍGUEZ BARRERA, J. BJÖRK, Materials Design Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden; Wallenberg Initiative Materials Science for Sustainability (WISE), IFM, Linköping University, Linköping, Sweden
Olefins, particularly ethene, are key building blocks in the chemical industry, obtained via cracking, a highly energy-intensive process, accounting for about 8% of the sector’s energy consumption [1]. An alternative route is offered by alcohol dehydration reaction, which reduces raw material use and optimizes atom economy, producing only olefins and water. This entropy-driven reaction becomes exergonic well below 100 °C but requires a catalyst that is capable of both donating and accepting hydrogen, typically a Brønsted acid. MXenes with mixed O and OH-terminations thus stand out as ideal candidates, as they would remain effectively unaltered after each catalytic cycle, fulfilling the key criterion of a true catalyst. In this study, we employ density functional theory together with transition state theory to evaluate the catalytic performance of mixed O/OH-terminated MXenes, with particular focus on titanium carbide MXenes. We resolve the full reaction pathway for ethanol dehydration to ethene, including both concerted and stepwise mechanisms, and assess the optimal conditions for catalysis. Our work indicates that these MXenes can serve as efficient catalysts, providing a foundation for future experimental validation.
[1] Ward et al., Catal. Sci. Technol. 13 (2023): 2638-264
CH-4:IL39 MXenes Functionality as Solid Lubricants Investigated by Ab Initio and Machine Learning Molecular Dynamics
M.C. RIGHI, Department of Physics and Astronomy "Augusto Righi", University of Bologna, Bologna, Italy
The ability of a 2D material to function as a solid lubricant depends on interlayer slipperiness and substrate adhesion—two properties often difficult to combine [1]. Our DFT simulations show that both are strongly governed by terminations [2]. Humidity significantly affects the tribological performance of solid lubricants. Our calculations reveal that on ideal –OH-terminated surfaces, physisorption prevails, whereas strong chemisorption occurs at defect sites—such as vacancies and edges—where undercoordinated Ti atoms promote H₂O dissociation [3]. We developed a machine learning potential capable of accurately describing MXenes interacting with H₂O and monitoring water splitting in real time through molecular dynamics (MD) simulations spanning time scales inaccessible to ab initio MD. Hybrid coatings combining Ti₃C₂Tₓ and MoS₂ were also tested under dry conditions, showing lower friction and enhanced wear resistance compared with their individual components [4], as confirmed by atomistic simulations. These results are part of the ERC-SLIDE project (Grant No. 865633).
[1] A. Rosenkranz et al., Adv. Mater. 35, 2207757 (2023); [2] E. Marquis et al., ACS Appl. Nano Mater. 5, 10516 (2022); [3] E. Marquis et al., Nano Converg. 10, 16 (2023); [4] G. Boidi et al., Carbon 225, 11906 (2024).
CH-4:IL40 Tuning the Electronic Structure of MXenes via Compositional Engineering
HUNG NGO MAHN, JI SOO BYUN, SANG UCK LEE, School of Chemical Engineering, Sungkyunkwan University, Suwon, Korea
Density functional theory (DFT) calculations were employed to elucidate the electronic and magnetic properties of two-dimensional MXene and i-MAX systems. In Ti₄N₃Tₓ, partial substitution of oxygen at nitrogen sites and mixed surface terminations (O and F) induce a moderate bandgap near the Fermi level, resulting in p-type semiconducting behavior with gate-tunable electrical conductivity. In contrast, (Mn₂/₃Mo₁/₃)₂AlC exhibits structure-dependent magnetic characteristics: the carbide phase remains thermodynamically stable, whereas the i-MAX phase shows variable spin ordering depending on its atomic arrangement. DFT results reveal that certain metastable i-MAX configurations can stabilize a ferromagnetic state through Mn–Mo–Al interactions and local lattice distortions. These findings underscore the electronic and magnetic tunability of Ti₄N₃Tₓ and (Mn₂/₃Mo₁/₃)₂AlC, providing design principles for multifunctional two-dimensional materials with potential electronic and magnetic applications.
CH-4:IL41 A Theoretical Perspective on Selective Etching—Predicting New 2D Materials
J. BJÖRK, Materials Design Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden; Wallenberg Initiative Materials Science for Sustainability (WISE), IFM, Linköping University, Linköping, Sweden
Computationally predicting the formation of two-dimensional (2D) materials formed by selective etching—such as MXenes—is particularly challenging due to the complexity of the underlying reactions. A theoretical model must capture the chemical environment during etching with sufficient accuracy while remaining efficient enough for large-scale screening. Here, we introduce theoretical methodologies for describing the selective etching of layered materials in various media. This includes an approach to model HF etching, first demonstrated for MXene synthesis [1], and later extended to a large-scale framework predicting the chemical exfoliability of ~100 layered compounds, culminating in the synthesis of 2D-Ru2SixOy in our laboratory [2]. Building on these insights, we further demonstrate a complementary framework to describe selective etching in molten salts, addressing the fundamentally different chemical and thermodynamic regimes involved [3], and conclude with an outlook toward alternative etching routes.
[1] J. Björk, J. Zhou, J. Halim and J. Rosen, npj 2D Mater. Appl. 2023, 7, 5; [2] J. Björk, J. Zhou, P. O. Å. Persson and J. Rosen, Science 2024, 383, 1210; [3] J. Björk and J. Rosen, Angew. Chem. Int. Ed. 2025, 64, e202506622.
CH-4:IL42 AI-promoting Discovery and Synthesis of New MAX and MAB Phases
YUELEI BAI, HANG YIN, ZHIYAO LU, XIAODONG HE, Harbin Institute of Technology, Harbin, P.R. China
An integrated AI-driven strategy is presented to accelerate the discovery and synthesis of MAX and MAB phases. First, a machine learning (ML) classification model was developed to rapidly predict the stability of MAX phases from elemental properties alone. This model successfully screened thousands of compositions, identified 150 new stable phases, and guided the first synthesis of Ti2SnN. Subsequently, the framework was extended to screen unconventional MAX phases featuring novel X-site elements (e.g., P, S, Se). Combined high-throughput DFT with an ANN-based ML classifier identified 210 stable phases from nearly 2,000 phases. An interpretable stability descriptor was provided, which ultimately led to the successful synthesis of a representative candidate, validating the model's accuracy. Furthermore, a ML regression model trained on DFT-calculated adiabatic temperatures was applied to evaluate the synthetic feasibility of Self-propagating High-temperature Synthesis (SHS) for MAX/MAB phases, without any experimental inputs. It pinpointed key descriptors and provided a general framework to quickly predict the SHS feasibility of any compounds from their elemental composition, guiding the synthesis of 5 phases like Nb2SB and the discovery of new V5PB2 by SHS.