MXenes are ultrathin transition-metal carbides, nitrides or carbonitrides with structures only a few atoms thick. Their unusual combination of electrical conductivity, mechanical flexibility, chemical tunability and large accessible surface area has made them attractive for batteries, supercapacitors, electromagnetic interference shielding, sensors and a range of emerging electronic devices. Unlike many two-dimensional materials, MXenes can be dispersed in liquids and processed into films, coatings and composite structures. Their properties can also be adjusted through changes in composition and surface chemistry, giving researchers a broad platform for designing materials with specific functions.

Most MXenes are produced from layered ceramic precursors known as MAX phases. These compounds contain alternating layers of transition-metal atoms and “A-site” elements, typically aluminium or related elements. Chemical etching removes the A layers while preserving the more strongly bonded transition-metal carbide or nitride sheets. Once the weaker interstitial layers have been selectively extracted, the remaining structure can be separated into thin MXene flakes. The challenge is to remove the desired atoms without damaging the robust two-dimensional framework, a balance that has traditionally required aggressive chemicals, extended reaction times and multiple purification steps.

Conventional synthesis routes include hydrofluoric acid etching, Lewis-acid etching and molten-salt treatment. Hydrofluoric acid can efficiently attack MAX phases, but it is highly corrosive and poses serious risks during handling, storage and waste treatment. Lewis-acid and molten-salt methods can avoid some of those hazards, yet they often require elevated temperatures, lengthy processing or substantial energy input. These limitations become increasingly important as demand grows and laboratories seek to move MXene production from small-scale experiments to industrial manufacturing. A synthesis route that is both fast and controllable could therefore influence not only the cost of MXenes but also the safety and environmental footprint of the entire materials pipeline.

The new approach, described by Xu, Yang, Zhu and colleagues, uses flash Joule heating to deliver an intense electrical pulse to the precursor material. Flash Joule heating can raise a material to very high temperatures in a fraction of a second, then allow it to cool rapidly once the pulse ends. In the reported process, the heating step is integrated with sequential chlorination and fluorination reactions. Rather than relying on slow diffusion through a liquid etchant, the method uses carefully controlled reaction conditions to promote selective chemical conversion and removal of the interstitial atoms within the MAX structure. The result is a rapid transformation from a layered precursor into a layered MXene product.

The central scientific challenge is selectivity. The atoms targeted for removal must react readily enough to leave the structure, while the transition-metal carbide or nitride layers must remain intact. According to the study, the researchers controlled both thermodynamic and kinetic parameters to guide this process. Thermodynamics determines which chemical transformations are favorable under the reaction conditions, while kinetics governs how quickly those transformations proceed and which pathways dominate. By tuning factors such as the reaction environment and heating profile, the team was able to promote the removal of the MAX phase’s interstitial atoms without triggering extensive decomposition of the desired two-dimensional framework.

The researchers applied the strategy to nine distinct MAX phases, demonstrating that the method is not limited to a single composition. This breadth is important because different MXenes offer different combinations of conductivity, surface reactivity, mechanical behavior and electrochemical characteristics. Producing multiple compositions through one general platform could make it easier to match a material to a specific application, whether the goal is rapid ion storage, electromagnetic absorption or integration into a flexible electronic device. The resulting MXenes were reported to have high structural quality and excellent electrochemical performance, suggesting that the rapid processing did not sacrifice the functional properties that make the materials valuable.

To understand how the transformation occurs, the team combined computational simulations with high-resolution transmission electron microscopy. The simulations were used to examine the selective-etching mechanism and identify how the chemical environment favors the removal of the targeted atoms. Meanwhile, electron microscopy provided direct views of structural evolution at the atomic scale, following the precursor as it changed from a MAX phase into a MXene. Such observations are especially significant for a rapid reaction, because many intermediate structures may exist only briefly. Connecting predicted reaction pathways with experimentally observed atomic arrangements gives researchers a stronger basis for refining the process and extending it to additional precursor chemistries.

The reported 30-second synthesis time places the method among the fastest approaches proposed for producing complex two-dimensional materials. Speed alone, however, is not enough for a manufacturing technology: the process must also deliver consistent products, use manageable quantities of reagents and maintain performance across different compositions. The study’s results indicate that sequential flash Joule heating-chlorination and fluorination, referred to as the FJH-ClF strategy, can address several of these requirements at once. Its rapid electrical heating may reduce the energy associated with long furnace treatments, while the selective chemistry could reduce the need for highly hazardous liquid etchants and intensive downstream processing.

The development arrives as researchers and manufacturers search for scalable ways to produce MXenes in quantities suitable for practical technologies. MXenes have already shown promise in laboratory demonstrations involving electrochemical energy storage, conductive coatings and electromagnetic shielding, but translating those demonstrations into commercial products requires reliable control over composition, layer structure, surface terminations and defect density. The FJH-ClF method could provide a route to that control by coupling short reaction times with a chemistry that is adaptable to multiple MAX phases. Its potential impact will ultimately depend on further studies of long-term stability, waste streams, reactor design, process uniformity and the performance of materials produced at larger scales. Even so, the work offers a striking example of how extreme, precisely controlled heating can replace slower and more hazardous chemical processing. By converting a difficult etching problem into a rapid sequence of thermal and chemical events, the researchers have presented a potentially safer and more sustainable pathway for manufacturing the MXenes that may underpin future energy, shielding and electronic technologies.

Subject of Research: Rapid synthesis of MXenes using sequential flash Joule heating, chlorination and fluorination

Article Title: Flash Joule heating for rapid MXenes synthesis

Article References: Xu, S., Yang, K., Zhu, H. et al. Flash Joule heating for rapid MXenes synthesis. Nat. Synth (2026). https://doi.org/10.1038/s44160-026-01132-2

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s44160-026-01132-2

Keywords: MXenes, flash Joule heating, FJH-ClF, MAX phases, chlorination, fluorination, two-dimensional materials, electrochemical energy storage, electromagnetic shielding, sustainable materials synthesis

The study, published in the prestigious journal Scientific Reports in 2026, explores the unexplored terrain of how calcium chloride concentrations affect the biological synthesis processes of silver nanoparticles (AgNPs) within lemon balm cultures cultivated under controlled laboratory conditions. Lemon balm, a medicinal herb revered for its rich pharmacological profile, serves as a biological nanofactory due to its diverse array of biomolecules capable of reducing silver ions and stabilizing synthesized nanoparticles.

Silver nanoparticles are extensively utilized across various industries due to their unique antimicrobial, catalytic, and conductive properties. Nonetheless, traditional chemical synthesis methods raise environmental and safety concerns. This has pivoted scientific interest toward biosynthesis strategies, leveraging plant extracts and cultures to produce nanoparticles in an eco-friendly manner. The present work pioneers the deliberate modulation of biosynthesis via calcium chloride, spotlighting its pivotal role in influencing nanoparticle characteristics such as size, shape, and surface chemistry.

Calcium ions, known for their central function in plant cellular signaling and structural integrity, appear to significantly impact the reduction kinetics and nucleation processes during nanomaterial formation. By introducing varied calcium chloride concentrations to in vitro culture media of lemon balm, the researchers provided compelling evidence that calcium can fine-tune the biosynthetic pathway. This fine-tuning, in turn, affects the yield, stability, and functional properties of the resulting silver nanoparticles.

Advanced characterization techniques employed in this study revealed that elevated calcium chloride levels enhanced the silver nanoparticle biosynthesis efficiency, yielding particles with smaller size distributions and improved dispersity. These attributes are critical because they directly correlate to the functional performance of nanoparticles, particularly in biomedical and environmental applications where uniformity and surface area dictate efficacy.

Beyond mere quantitative improvements, calcium chloride was shown to influence the phytochemical milieu of the lemon balm cultures. This alteration likely modifies the repertoire of reducing agents and capping molecules secreted by the plants, which play vital roles in the in situ reduction of silver ions and stabilization of nascent nanoparticles. Such insights open avenues toward tailored nanoparticle synthesis by manipulating plant metabolic pathways through mineral nutrient regimes.

The implications of this research extend far beyond the laboratory bench. A calcium chloride-modulated biosynthesis platform offers an environmentally benign, scalable route to produce silver nanoparticles with bespoke characteristics. This approach could revolutionize nanomaterial production by integrating agricultural biotechnology with nanoscience, substantially reducing reliance on toxic chemicals and energy-intensive processes commonly associated with nanoparticle synthesis.

In terms of applications, silver nanoparticles generated via this calcium chloride-mediated biosynthesis could enhance antimicrobial coatings, targeted drug delivery systems, and environmental remediation technologies. Moreover, the tunability of nanoparticle properties afforded by calcium modulation enables researchers and industry stakeholders to customize nanoparticles for specific functionalities, potentially improving safety and performance profiles.

Fundamentally, this research sheds light on the intricate interplay between mineral nutrient levels and plant-mediated nanoparticle synthesis mechanisms. It posits that calcium chloride does not merely act as an inert additive but functions as a biochemical signal transducer capable of reprogramming biosynthetic pathways, paving the way for precision nanosynthesis in living plant systems.

Moreover, the use of in vitro-grown lemon balm as the biological chassis ensures reproducibility and consistency, which are often barriers when employing raw plant extracts. Controlled in vitro conditions mitigate variability caused by environmental factors, delivering a robust platform for industrial-scale nanoparticle production endowed with high-quality standards.

The research also highlights the necessity to delve deeper into plant physiology and metabolic engineering to further exploit calcium’s role in nanoparticle biosynthesis. Understanding the molecular basis of calcium-mediated modulation could provide strategies to unlock a spectrum of metal nanoparticles beyond silver, expanding the green nanotechnology toolkit.

The findings underscore the ecological and economic advantages of merging plant sciences and nanotechnology, fostering sustainable innovation ecosystems that align with the principles of green chemistry and circular economy. By harnessing the latent capabilities of plants through mineral modulation, researchers are charting a futuristic paradigm where nature-informed engineering solves critical technological challenges.

In conclusion, the pioneering work by Piretarighat, Ghannadnia, and Baghshahi establishes a new frontier in the biosynthesis of silver nanoparticles, situating calcium chloride as a key agent in governing nanoparticle formation and characteristics in lemon balm cultures. This breakthrough not only enhances our fundamental understanding but also propels the practical realization of greener and smarter nanoparticle manufacturing.

As industries increasingly emphasize sustainability without compromising performance, such biotechnological innovations are expected to catalyze transformative shifts in material science and nanomedicine. The promising outcomes of this study beckon further interdisciplinary research exploring fine-scale nutrient regulation as a lever for controlled biosynthesis of advanced nanomaterials.

For the broader scientific community, this study exemplifies how integrative approaches combining plant biology, chemistry, and nanotechnology can yield novel solutions addressing pressing environmental and technological imperatives. The tunable and eco-friendly nature of calcium chloride-mediated nanoparticle synthesis heralds a new era where living plants become programmable nanofactories, crafting materials with unparalleled precision and minimal ecological footprint.

Subject of Research: Biosynthesis of silver nanoparticles modulated by calcium chloride in in vitro-grown lemon balm plants.

Article Title: Calcium chloride modulates the biosynthesis capability and properties of silver nanoparticles synthesized from in vitro-grown lemon Balm.

Article References:
Piretarighat, S., Ghannadnia, M. & Baghshahi, S. Calcium chloride modulates the biosynthesis capability and properties of silver nanoparticles synthesized from in vitro-grown lemon Balm. Sci Rep (2026). https://doi.org/10.1038/s41598-026-55702-7

Image Credits: AI Generated