In a remarkable breakthrough that could transform the landscape of two-dimensional materials, researchers have unveiled a novel synthesis technique that generates MXenes with unprecedentedly uniform and precisely controlled surface terminations. This advance addresses a longstanding challenge inherent to these promising compounds, significantly boosting their electronic properties and opening new avenues for their utilization in next-generation technologies.
MXenes, first discovered just over a decade ago in 2011, represent a versatile family of inorganic two-dimensional materials comprising layers of transition metals combined with carbon or nitrogen atoms. What sets MXenes apart are the atoms, known as surface terminations, that cap the outermost layers. These terminations critically influence the material’s behavior—controlling electron transport, stability, and interactions with light and heat. Until now, however, MXenes have been limited by the uncontrolled, heterogeneous distribution of these surface groups, discovered through conventional chemical etching techniques.
Traditional MXene synthesis leverages chemical etching methods involving harsh acids or reactive chemicals that produce a patchwork of oxygen, fluorine, chlorine, and sometimes other terminations scattered randomly on the surface. This disorder leads to electron scattering akin to potholes on a highway, severely impeding charge mobility and undermining the potential of MXene-based devices. Recognizing these bottlenecks, a collaborative research team led by scientists at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and TU Dresden pioneered an alternative strategy, deftly circumventing these constraints.
Their new method—termed the GLS synthesis route—eschews harmful chemicals altogether, instead deploying a triphasic system that involves solid MAX phases, molten salts, and iodine vapor in a carefully orchestrated reaction environment. This triphasic setup allows the researchers to dictate exactly which halogen atoms terminate the MXene surfaces, such as chlorine, bromine, or iodine, creating well-ordered, homogeneous surface configurations and dramatically lowering impurities. This level of control, unparalleled in the field, fundamentally alters MXene performance.
Demonstrating the robustness of this synthesis, the team synthesized MXenes from eight distinct MAX phases, underscoring the method’s versatility and broad applicability across the MXene family. To complement their experimental efforts, density functional theory (DFT) calculations provided deep theoretical insight into how these precisely engineered terminations stabilize the structure and govern electronic properties. The fusion of empirical and computational approaches guided the development of MXenes with tailored functional characteristics and enhanced stability.
One compelling example illustrating the leap in performance is the titanium carbide MXene Ti₃C₂. In conventional chemical etching, Ti₃C₂ terminates with a mixture of chlorine and oxygen—a combination that muddles its intrinsic electronic properties. However, when synthesized via the GLS method, Ti₃C₂Cl₂ exhibited a perfectly chlorine-terminated surface, meticulously ordered with no detectable contaminants. The performance improvements were staggering: macroscopic conductivity surged by a factor of 160, terahertz-frequency conductivity increased thirteenfold, and electron charge carrier mobility skyrocketed nearly four times higher.
These phenomena stem directly from the ordered surface halogens acting as a smooth highway for electron travel, free of the impediments that plagued previous MXenes. Quantum transport simulations reinforced these experimental outcomes, revealing that the uniform chlorine termination dramatically minimized electron trapping and scattering events at the atomic scale. This clear microscopic understanding validates the technique’s power to unlock the intrinsic potential of MXenes.
The implications extend far beyond electrical conductivity. By varying the halogen type, researchers observed altered absorption profiles of electromagnetic radiation across different frequency bands. Chlorine-terminated MXenes strongly absorb waves in the 14-18 GHz range, while bromine- and iodine-terminated variants interact uniquely with other regions of the electromagnetic spectrum. This tunable absorption makes MXenes viable candidates for tailor-made radar-absorbing coatings, electromagnetic interference shielding, and emerging high-frequency wireless communication components.
Even more striking is the ability to “dial in” mixed halogen terminations by blending halide salts, yielding dual or triple surface terminations with precise compositional control. This strategy unlocks an unprecedented material design space where electronic, catalytic, energy storage, and photonic properties can be finely tuned for specific target applications. The method transforms MXene surface chemistry from an uncontrolled inevitability into a deliberate design parameter, laying the groundwork for highly customized two-dimensional materials.
Crucially, the GLS synthesis method stands out for its gentleness and environmental friendliness compared to traditional aggressive chemical approaches. By eliminating toxic reagents and facilitating synthesis under moderate conditions, the process not only produces superior materials, but also aligns with sustainable manufacturing principles—a key consideration for future scalability in industrial settings.
This breakthrough heralds a new era for MXene chemistry and engineering. As the field transitions from MXene discovery to application, the ability to fabricate materials with atomically precise surface configurations empowers researchers to exploit their full range of electrical, optical, and chemical functionalities. The method promises to accelerate innovation in flexible electronics, rapid data transmission technologies, and next-generation optoelectronics.
Looking forward, the research community anticipates that the GLS synthesis approach will serve as a foundational platform upon which even more complex and multifunctional MXene architectures can be built. By marrying theoretical predictions with experimental precision, scientists are poised to explore the vast combinatorial landscape of MXene surface chemistries, optimizing materials for an array of cutting-edge technologies.
In sum, the triphasic GLS method represents a paradigm shift in MXene fabrication, yielding materials with highly ordered, impurity-free halogen terminations tailored to specific properties. The dramatic enhancement of electrical transport, along with the ability to customize electromagnetic response, promises to expand the applications of MXenes far beyond their current scope. As researchers continue to unlock the secrets of these surfaces, the stage is set for MXenes to become cornerstone materials of the next technological revolution.
Subject of Research: Not applicable
Article Title: Triphasic synthesis of MXenes with uniform and controlled halogen terminations
News Publication Date: 6-Jan-2026
References:
DOI: 10.1038/s44160-025-00970-w
Image Credits:
HZDR/B. Schröder
Keywords: MXenes, two-dimensional materials, surface terminations, halogenation, GLS synthesis method, electronic properties, titanium carbide Ti₃C₂, density functional theory, quantum transport simulations, electromagnetic absorption, flexible electronics, advanced optoelectronics
