The Seebeck effect lies at the heart of thermoelectric textiles. When one side of a material is hotter than the other, charge carriers diffuse from the hot region to the cold one, generating a measurable voltage. The ratio of that voltage to the temperature gradient defines the Seebeck coefficient, the central parameter for any thermoelectric material. Because the human body maintains a temperature of roughly 37 degrees Celsius against an ambient surroundings that is often cooler, clothing that exploits this gradient could, in principle, trickle-charge sensors, health monitors, and other smart textile devices without batteries. Cotton is a natural substrate for such applications: it is the most widely used fabric in the fashion industry, comfortable against the skin, and compatible with established coating techniques.

The challenge has always been how to make cotton conductive without destroying its textile character. Carbon nanomaterials such as carbon nanotubes and carbon nanofibers offer promising electronic properties, but they are typically produced as solid powders that resist integration into fabrics. The standard workaround is to disperse them into inks, which can then be applied by screen printing, inkjet printing, spray coating, or dip coating. In this study, the researchers formulated aqueous inks containing two Pyrograf III carbon nanofiber grades, PR 24 LHT XT and PR 25 PS XT, both synthesized by chemical vapor deposition at 1,100 degrees Celsius but subjected to different post-synthesis thermal treatments: 1,500 degrees Celsius for the PR 24 grade and 700 degrees Celsius for the PR 25 grade. These treatments strip a polyaromatic carbon layer from the nanofiber surfaces, and they leave the two grades with distinct structural signatures.

Transmission electron microscopy revealed that both nanofibers share a double-walled structure enclosing a hollow tubular core, with an inner layer of compacted parallel graphene sheets oriented at an angle to the core axis and a more disordered outer layer. The PR 24 fibers, however, have smaller total diameters of 80 to 100 nanometers compared with 125 to 150 nanometers for PR 25, and Raman spectroscopy confirmed that PR 24 possesses higher crystallinity, showing narrower D and G bands and a detectable 2D mode. The fabrics were functionalized by repeated immersion in inks containing 1.6, 3.2, or 6.4 milligrams of nanofibers per milliliter of distilled water, stabilized with the surfactant sodium dodecybenzenesulfonate, followed by drying cycles and rinsing steps to remove surfactant residues. Scanning electron microscopy showed that at the lowest concentration the cotton weave remained largely visible, while at 6.4 milligrams per milliliter an entangled mat of nanofibers completely covered the fabric surface, with the fibers concentrated near the surface rather than penetrating the full weave.

Thermogravimetric analysis under nitrogen confirmed that all coated fabrics remained thermally stable up to 300 degrees Celsius, matching the behavior of uncoated cotton, and revealed that the fabrics coated with the most concentrated inks carried approximately 8 to 9 percent nanofiber content by weight. At the highest concentration, the residue percentages at 600 degrees Celsius converged to about 18 to 19 percent for both nanofiber types, indicating that the coating had reached saturation and become homogeneous. This saturation point proved decisive for the electrical performance of the resulting conductive textiles.

The thermoelectric measurements at 30 degrees Celsius told a nuanced story. Both nanofiber types, measured in agglomerated solid form, showed similar electrical conductivities of roughly 133 to 136 siemens per meter, values that represent a practical ceiling for textile applications using simple dispersion methods. The coated fabrics, however, diverged depending on ink concentration: at the lowest loading, fabrics coated with the thicker PR 25 fibers actually conducted better, reaching 5.1 siemens per meter, while at the highest loading the PR 24 fabrics took the lead, achieving 35.4 siemens per meter against 23.2 for PR 25. Both fabric types exhibited negative Seebeck coefficients, confirming n-type conduction, with PR 24-based textiles reaching about minus 6 microvolts per kelvin compared with minus 1 for PR 25. Intriguingly, the absolute Seebeck values of the fabrics exceeded those of the corresponding nanofibers, a phenomenon the researchers attribute to slight electron doping from adsorption between the graphitic planes and cellulose molecules, and possibly from residual surfactant.

Combining these parameters, the best fabric, coated with the highest concentration of PR 24 nanofibers, achieved a power factor of approximately 1.2 times 10 to the minus 3 microwatts per meter per square kelvin. Using a novel null-point scanning thermal microscopy method, the team measured the thermal conductivity of the coated fabrics at just 0.06 watts per meter per kelvin, only twice that of uncoated cotton and far below the values typical of carbon nanotube-filled polymer composites. This low thermal conductivity is a genuine advantage for thermoelectric applications, since it keeps heat from leaking across the gradient. The resulting figure of merit, zT, reached approximately 6.3 times 10 to the minus 6 at 30 degrees Celsius, modest compared with inorganic thermoelectrics but notable for a flexible textile and higher than values previously reported for the same nanofibers in melt-mixed polymer composites.

The temperature dependence of the electrical conductivity between 30 and 100 degrees Celsius revealed perhaps the most striking result. While the nanofibers themselves showed a positive temperature coefficient, with conductivity decreasing as temperature rose, the coated fabrics behaved in the opposite way, exhibiting a negative temperature coefficient. The best PR 24 fabric increased from 35.4 to 45.0 siemens per meter across the range, and the PR 25 fabric rose from 23.2 to 29.5. Fitting the data to a three-dimensional variable range hopping model showed that the fabrics conduct through thermally activated hopping of charge carriers across a random network of potential wells, with mean energy potentials of roughly 15 electronvolts, whereas the nanofibers alone conduct through thermally enhanced backscattering from impurities or structural defects. In other words, coating the fibers onto cotton fundamentally changes the transport mechanism.

The Seebeck coefficients of the fabrics also grew in absolute value with temperature, from minus 6.1 to minus 7.5 microvolts per kelvin for the lowest-concentration PR 24 fabric. Modeling this nonlinear behavior with an approach developed for doped multi-walled carbon nanotube mats suggested that the PR 24 fabrics are more likely to be negatively doped, consistent with electron donation from the cellulose fibers or the surfactant used in the ink formulation. The PR 25 fabrics, by contrast, retained a positive metallic term in the model, indicating a different doping character despite their similar structure.

Overall, the study demonstrates that despite meaningful structural differences between the two Pyrograf III grades, the resulting conductive textiles are remarkably similar in their thermoelectric properties, with the smaller-diameter, more crystalline PR 24 fibers holding a slight edge at high ink concentrations. The researchers suggest these n-type carbon nanofiber textiles could serve as reference materials for future studies combining them with other n-type organic or inorganic components, moving toward a new generation of flexible, wearable thermoelectric generators that draw power directly from the temperature difference between our bodies and the world around us.

Subject of Research: thermoelectric cotton textiles coated with Pyrograf III carbon nanofibers

Article Title: Comparative study of thermoelectricity in cotton fabrics coated by immersion with Pyrograf® III carbon nanofibers-based inks

Article References: Paleo, A. J., Abreu, J., Krause, B., González-Casal, S., Thomas, L., Cerqueira, M. F., Muñoz, E., & Pötschke, P. (2026). Comparative study of thermoelectricity in cotton fabrics coated by immersion with Pyrograf® III carbon nanofibers-based inks. Frontiers in Materials, 13, Article 1933448. https://doi.org/10.3389/fmats.2026.1933448

Image Credits: AI Generated

DOI: 10.3389/fmats.2026.1933448

Keywords: thermoelectric textiles, carbon nanofibers, cotton fabrics, n-type conduction, smart textiles, wearable energy harvesting, dip coating, Seebeck effect, Comparative, thermoelectricity, cotton, fabrics

The appeal of catalytic methane decomposition, often abbreviated CMD, lies in its chemistry. Instead of reacting methane with steam at punishing temperatures and venting carbon monoxide and dioxide, CMD breaks the methane molecule apart thermally, yielding hydrogen gas and solid carbon as the only products. The process typically operates between 700 and 900 degrees Celsius, cooler than many conventional reforming routes, and the carbon by-product is not merely waste: filamentous carbon of the kind produced in these reactions has industrial value in polymers, electrodes, and composites. In the color-coded taxonomy of hydrogen production, this places CMD-derived hydrogen in the blue category, a potentially cleaner bridge between today’s fossil-based grey hydrogen and tomorrow’s green hydrogen from electrolysis.

The challenge has always been the catalyst. Nickel is the champion of methane activation among the group VIII transition metals, outperforming iron and cobalt in conversion tests, but nickel catalysts deactivate rapidly above 600 degrees Celsius as carbon deposits bury the active sites and particles sinter together. Iron, by contrast, is cheap, abundant, and more resistant to deactivation, though less active on its own. Bimetallic nickel-iron systems have emerged as a compromise, with earlier studies showing that pairing the two metals improves both methane conversion and the formation of carbon nanofibers. Alharthi’s previous work on unsupported NiFe2O4 had shown that catalytic efficiency depends strongly on reaction and calcination conditions, prompting the question of whether a support could push performance further.

To answer it, the researcher synthesized NiFe2O4 nanoparticles through a wet-chemical co-precipitation route, dissolving ferric and nickel nitrates in water, raising the pH to 10 with ammonium hydroxide, and calcining the resulting solid at 500 degrees Celsius. The ferrite powder was then physically mixed in equal weight proportions with either H-ZSM-5 zeolite or silica, and the composites were calcined again. The two supports were chosen deliberately: H-ZSM-5 brings a porous crystalline framework, high surface area, and intrinsic acidity, while silica offers hydrothermal stability and mesoporosity but no acidity of its own. These differences in texture and chemistry were expected to influence how the ferrite dispersed, how easily it reduced, and ultimately how well it cracked methane.

Characterization revealed a spinel phase with a mesoporous structure uniformly distributed over both supports. Electron microscopy showed the H-ZSM-5 composite as agglomerated pebbles with smaller particles, while the silica composite displayed a bulkier, flatter morphology covered with finely dispersed nanoparticles. Nitrogen adsorption measurements told a subtler story: loading the ferrite onto silica produced a composite with a surface area of 156.2 square meters per gram, far above the 43 square meters per gram of the unsupported oxide, whereas the zeolite composite lost surface area relative to pure H-ZSM-5, apparently because ferrite particles partially blocked the zeolite’s channels. X-ray diffraction confirmed the spinel structure alongside a minor hematite phase, and crystallite sizes came out at 15.45 nanometers for the zeolite-supported material versus 18.13 nanometers for the silica-supported one.

Perhaps the most revealing measurements came from temperature-programmed reduction with hydrogen. For the H-ZSM-5 composite, a small reduction peak at 403 degrees Celsius signaled the presence of free or weakly bound nickel oxide that converts readily to metallic nickel, alongside the main iron-reduction steps near 563 and 683 degrees Celsius. The silica-supported material lacked this distinct nickel oxide peak, and the authors concluded that it reduces predominantly to a nickel-iron alloy. In other words, the zeolite-supported catalyst offers easily reduced nickel species that become active almost immediately, while the silica-supported catalyst must undergo a slower, more gradual transformation under reaction conditions before its active phase emerges.

That distinction played out exactly as predicted in the reactor. Testing 0.5 grams of unreduced catalyst at 800 degrees Celsius with a methane-nitrogen feed of 20 milliliters per minute, the H-ZSM-5 composite showed no induction period at all, reaching a peak methane conversion of 40.6 percent and a hydrogen formation rate of 83.5 by ten-to-the-minus-five moles per gram per minute after 120 minutes, before slipping slightly to about 38.5 percent by 300 minutes as carbon accumulated. The silica composite behaved differently: it needed roughly 150 minutes to activate, but then reached about 40 percent conversion and 82.3 by the same units with sustained activity through the end of the run. The zeolite catalyst wins on speed; the silica catalyst wins on staying power.

Analysis of the spent catalysts explained both behaviors. X-ray diffraction showed that the original spinel structure had been consumed, replaced by a strong nickel-iron alloy peak, with residual ferrite persisting in both samples—a likely contributor to the long-term stability. The zeolite-supported catalyst also displayed a peak for iron carbide, Fe3C, itself a known active phase for methane decomposition, providing an extra catalytic boost. Electron microscopy revealed dense layers of filamentous carbon covering both spent catalysts, and thermogravimetric analysis quantified the deposits at 52 weight percent for the H-ZSM-5 composite against 23 weight percent for the silica composite, mirroring the former’s early and vigorous activity. Raman spectroscopy confirmed highly graphitized carbon, with defect-to-graphite intensity ratios of 0.346 and 0.25 respectively, indicating well-ordered graphitic structures on both.

Compared with other supported ferrites reported in the literature, the results are striking. NiFe2O4 on magnesia achieved a similar conversion but deactivated after 200 minutes, while the same ferrite on alumina or titania managed conversions of only 2.1 and 5.2 percent. Bimetallic nickel-iron catalysts on conventional supports can reach higher conversions of 59 to 80 percent, but they tend to suffer shorter operational lifetimes, which makes the balanced activity and stability of these two new composites noteworthy. The study also found that the H-ZSM-5-supported ferrite outperformed the previously studied cobalt ferrite on the same zeolite in both hydrogen formation and carbon yield under identical conditions, underscoring the advantage of the nickel-iron pairing.

The broader lesson is that support selection is not a passive detail but an active design lever. The zeolite’s channels and acidity disperse the ferrite, accelerate its reduction, and boost early activity and carbon production, while silica’s gentler interaction with the oxide delays activation but sustains it. For a hydrogen economy that needs practical, low-emission production routes in the interim, catalysts that turn methane into fuel-grade hydrogen plus saleable carbon nanofibers—without a smokestack in sight—represent a compelling piece of the puzzle, and this work maps out precisely which levers to pull when designing them.

Subject of Research: Support-tuned nickel ferrite catalysts for catalytic methane decomposition to produce hydrogen and filamentous carbon

Article Title: Tuning NiFe2O4 catalysts with support materials for enhanced methane cracking and hydrogen production

Article References: Alharthi, A. I. (2026). Tuning NiFe2O4 catalysts with support materials for enhanced methane cracking and hydrogen production. Journal of Saudi Chemical Society, 30(3), Article 30. https://doi.org/10.1007/s44442-026-00074-w

Image Credits: AI Generated

DOI: 10.1007/s44442-026-00074-w

Keywords: nickel ferrite, methane decomposition, hydrogen production, H-ZSM-5, silica support, spinel catalyst, Ni-Fe alloy, filamentous carbon, catalytic methane cracking, blue hydrogen, temperature-programmed reduction, carbon nanofibers

The motivation for the work lies in the well-known weaknesses of enzyme-based glucose sensors, which dominate the commercial market but degrade when exposed to fluctuations in pH, temperature, or humidity. Enzymes are fragile biological molecules, and their activity drifts over time, complicating long-term monitoring. Nonenzymatic sensors replace the enzyme with an inorganic catalyst, trading some biochemical specificity for dramatically improved stability and shelf life. Among inorganic catalysts, nickel-based materials have long been favored because they are cheap, abundant, and highly active toward glucose oxidation in alkaline media, but their performance depends critically on how much catalytic surface area can be packed onto an electrode.

The Iranian team, led by Mohadeseh Haghkhah and Rahim Mohammad-Rezaei, addressed that surface-area problem with a two-step electrochemical strategy. First, they electrodeposited a nickel-copper alloy onto a flat graphitic electrode that had been coated with a composite of acid-treated carbon nanofibers and sulfur-nitrogen co-doped graphene quantum dots. The deposition was performed at minus 0.9 volts for 120 seconds in a solution containing nickel chloride, copper chloride, and boric acid. Then came the crucial dealloying step: applying a positive potential of 0.2 volts for 180 seconds selectively dissolves copper from the alloy while nickel, which rapidly forms a protective passive oxide layer, stays behind.

The choice of dealloying potential proved decisive. At 0.1 volts, substantial copper remained on the surface, confirmed by residual copper redox peaks in cyclic voltammetry. At 0.5 volts, the process became too aggressive and significant nickel leached away alongside the copper. Energy-dispersive X-ray spectroscopy and amperometric current-time traces both pointed to 0.2 volts as the sweet spot, where copper removal was nearly complete while nickel loss was minimized. Scanning electron microscopy revealed the dramatic morphological consequence: the spherical NiCu nanoparticles collapsed into needle-like nickel structures with vastly increased electroactive surface area, a transformation that simply did not occur when the dealloying step was skipped.

The underlying scaffold is just as important as the nanoneedles themselves. Carbon nanofibers, roughly 60 to 100 nanometers in diameter, were activated with a sulfuric and nitric acid treatment that replaced surface-bound oxides with hydroxyl groups, boosting hydrophilicity. The graphene quantum dots, synthesized hydrothermally from citric acid and thiourea, were confirmed by infrared spectroscopy and fluorescence measurements, showing characteristic blue emission at 443 nanometers. Raman spectroscopy tracked the whole transformation: copper oxide vibrational bands visible in the alloyed electrode vanished almost entirely after dealloying, while bands associated with nickel oxyhydroxide and hydroxide phases emerged, providing direct spectroscopic evidence that the copper had been stripped and the nickel converted to its active form.

Electrochemical impedance spectroscopy quantified the synergy between the components. The charge-transfer resistance of the full composite shrank progressively as carbon nanofibers and then quantum dots were added, and dropped again after copper removal. Cyclic voltammetry showed quasi-reversible nickel(II)/nickel(III) redox peaks at approximately 0.29 and 0.5 volts, and the electroactive surface area, calculated by charge integration, told a striking story: 0.146 square centimeters for nanoneedles on bare graphite, 2.49 square centimeters with carbon nanofibers, and 6.00 square centimeters with the full carbon nanofiber-quantum dot composite. In other words, the nanostructured scaffold multiplied the effective catalytic area more than fortyfold relative to the plain electrode.

Glucose oxidation on the finished electrode follows a well-understood electrochemical-chemical mechanism. In the anodic scan, surface nickel hydroxide is electrochemically oxidized to nickel oxyhydroxide, the true catalytic species. Glucose then reduces nickel oxyhydroxide back to nickel hydroxide while being converted to gluconolactone, and the regenerated nickel hydroxide is oxidized again, sustaining a continuous catalytic cycle that amplifies the anodic current. Scan-rate studies confirmed that peak currents scaled linearly with scan rate, consistent with this surface-confined redox cycle. Crucially, the un-dealloyed NiCu electrode showed essentially no sensitivity to glucose, demonstrating that residual copper participates in parasitic side reactions and disrupts the nickel redox kinetics that the sensing mechanism depends on.

The analytical figures of merit are impressive. Operating at 0.40 volts in 0.1 molar potassium hydroxide, the optimized sensor achieved a sensitivity of 2105.95 microamperes per millimolar per square centimeter, a linear range spanning 0.012 to 12 millimolar, and a detection limit of 3.13 micromolar, with a response time of about five seconds. That sensitivity represents a 240 percent improvement over electrodes lacking either the quantum dots or the dealloying treatment, and it compares favorably with recently reported nickel-based nonenzymatic sensors built on MoS2, MXenes, and layered double hydroxides. Selectivity tests showed that physiologically relevant concentrations of ascorbic acid, dopamine, citric acid, uric acid, and sodium chloride produced negligible signal changes, with interference fluctuations staying below five percent.

Reliability testing reinforced the platform’s practical credentials. Three independently fabricated electrodes gave responses with a relative standard deviation of just 3.5 percent, and repeated measurements on a single electrode yielded 4.15 percent. The amperometric signal remained stable for more than 1500 seconds of continuous operation, and the electrode retained its performance over four weeks of storage with only 3.19 percent variation. In real-world validation, the team deproteinized human serum with acetonitrile, added just 15 microliters of the treated serum to the micro-drop cell, and measured a glucose concentration of 4.90 millimolar using the standard addition method, with spike recoveries between 97.22 and 102.82 percent. Commercial glucometers read the same samples at 5.01 millimolar, a statistically indistinguishable result.

The micro-drop platform itself may prove as consequential as the nanomaterials. Built from air-dry modeling clay, epoxy resin, and flat graphitic electrodes arranged radially around a well of at most 800 microliters, it is inexpensive, reusable, and ideally suited to clinical samples where volume is scarce. Unlike disposable screen-printed electrodes, the flat platform can be regenerated and monitored over the long term. The authors suggest the combination of low cost, straightforward fabrication, micro-volume capability, and serum-level accuracy positions the sensor for point-of-care diagnostics and sample-limited biomedical assays, offering a glimpse of how rational nanoscale engineering, in this case the simple act of etching copper out of an alloy, can translate into clinically meaningful analytical performance.

Subject of Research: Nonenzymatic electrochemical glucose sensing using alloying-dealloying activated NiOOH nanoneedles on carbon nanofiber-graphene quantum dot composites

Article Title: Electrochemical alloying-dealloying driven activation of NiOOH nanoneedles on carbon nanofiber-graphene quantum dot composites for nonenzymatic glucose sensing on a micro-drop flat platform

Article References: Electrochemical alloying-dealloying driven activation of NiOOH nanoneedles on carbon nanofiber-graphene quantum dot composites for nonenzymatic glucose sensing on a micro-drop flat platform. (n.d.). https://doi.org/10.1016/j.rechem.2026.103905

Image Credits: AI Generated

DOI: 10.1016/j.rechem.2026.103905

Keywords: glucose sensor, nonenzymatic sensing, NiOOH nanoneedles, dealloying, carbon nanofibers, graphene quantum dots, electrodeposition, micro-drop electrode, electrocatalysis, human serum, point-of-care diagnostics, electrochemical biosensor

The active ingredient of the ink is a pseudocapacitive spinel oxide, tin cobalt oxide with the chemical formula SnCo2O4, combined with conductive carbon nanofibers. Spinel oxides of this kind are attractive for electrochemical applications because their crystal structure offers multiple accessible oxidation states, allowing fast and reversible redox reactions at the electrode surface. In an energy storage context, this pseudocapacitive behaviour means charge is stored not only electrostatically at the interface between electrode and electrolyte, as in a conventional double-layer capacitor, but also through faradaic charge-transfer reactions that can substantially increase the amount of energy packed into a given area. The carbon nanofibers serve as a highly conductive skeletal framework that threads through the oxide particles, providing continuous pathways for electrons and helping to anchor the active material mechanically.

Screen printing was chosen as the deposition technique because it is one of the most manufacturing-friendly methods available for printed electronics. In screen printing, a viscous paste or ink is forced through a patterned mesh onto a substrate, allowing large areas to be patterned quickly with minimal material waste and without the vacuum equipment or photolithography required by conventional microfabrication. The challenge lies in formulating an ink whose rheology, viscosity, and solids loading allow clean transfer through the mesh while retaining the electrochemical activity of the functional particles. The researchers optimised the composition of the SnCo2O4 and carbon nanofiber blend, identifying a formulation designated SC-3 that delivered the best balance of conductivity, printability, and charge-storage performance.

When printed as micro-supercapacitor electrodes, the SC-3 material exhibited both pseudocapacitive and electric double-layer capacitive charge-storage mechanisms, a hybrid behaviour that combines the high power and long cycle life of double-layer storage with the higher capacitance of faradaic materials. The printed electrodes achieved an areal capacitance of 673.8 plus or minus 3.1 millifarads per square centimetre, an energy density of 93.58 plus or minus 1.5 microwatt-hours per square centimetre, and a power density of 1.353 plus or minus 3.0 milliwatts per square centimetre. These figures were reported with a relative standard deviation below one percent across three replicate measurements, indicating a high degree of reproducibility in the printing process. For microscale energy applications, where the electrode area is measured in square centimetres or less, such areal metrics are the relevant benchmarks rather than gravimetric values.

The same ink proved equally capable when deployed in sensing devices. A humidity sensor printed from the SC-3 formulation showed excellent operational stability, fast response and recovery times of 38 and 56 seconds respectively, low hysteresis of 1.46 percent, and a wide detection range spanning relative humidity values from 11 to 97 percent. Low hysteresis is a particularly important figure of merit for humidity sensors because it reflects how consistently the sensor returns to its baseline resistance after exposure to moist and dry conditions, a property that determines whether repeated measurements can be trusted without recalibration. The wide dynamic range means a single printed sensor could operate reliably in environments as different as dry indoor air and near-saturated tropical conditions.

The third application demonstrated by the team is arguably the most medically significant. When the SC-3 material was used to modify a screen-printed electrode, abbreviated SPE, the resulting electrochemical sensor exhibited excellent behaviour in detecting naproxen, a widely used non-steroidal anti-inflammatory drug. The sensor operated across a broad drug concentration range from 1 micromolar to 500 micromolar, covering concentrations relevant to both pharmaceutical quality control and environmental monitoring of waterways, where accumulated drug residues have become an emerging concern. Long-term stability testing showed that the sensor could measure naproxen reliably in tablet samples and in synthetic urine, with a relative standard deviation of 3.53 percent, plus or minus 0.72, demonstrating practical analytical performance beyond idealised laboratory conditions.

The researchers attribute the multifunctional performance to the interplay between the carbon nanofiber framework and the redox-active SnCo2O4. The nanofibers create a percolating conductive network that lowers the overall resistance of the printed film, while the spinel oxide contributes abundant active sites for both faradaic charge storage and surface reactions involved in sensing. In the humidity sensor, the oxide surface likely adsorbs water molecules and facilitates proton conduction, while in the electrochemical sensor the redox-active oxide catalyses the electron-transfer reaction of naproxen at the electrode surface. A single material satisfying these distinct physical mechanisms is what makes the platform genuinely multifunctional rather than a collection of coincidental performances.

The broader significance of the work lies in how it tackles the shortcomings of conventional standalone energy storage and sensing devices. Traditionally, a designer building a self-powered sensing node would need to integrate a supercapacitor made of one material system with a sensor made of another, often requiring incompatible deposition processes, adhesion layers, and thermal treatments. A single ink that can be printed into any of these device architectures simplifies supply chains, reduces fabrication steps, and opens the door to fully printed integrated systems in which energy storage and sensing elements are deposited side by side on the same substrate in the same manufacturing run. This is precisely the kind of process integration that printed electronics and the Internet of Things have long demanded.

The study also carries implications for sustainability and cost. Tin and cobalt oxides are relatively abundant compared with some of the precious-metal catalysts used in high-end electrochemical sensors, and carbon nanofibers can be produced at scale. Because the ink is screen-printable at ambient conditions, it does not require energy-intensive vacuum deposition, and the additive nature of printing means far less material is wasted compared with etch-based patterning. The authors describe their formulation as a scalable, affordable, multifunctional conductive ink platform aimed squarely at next-generation miniaturised microelectronics, positioning it as a practical route from laboratory materials chemistry to manufacturable devices.

The research, led by Shilpa Shetty, Mohammad Saquib, Selvakumar M, and Ramakrishna Nayak at the Manipal Institute of Technology, was published open access on 11 September 2026 in Advanced Composites and Hybrid Materials, with Shetty supported by a Dr T. M. A. Pai Fellowship from the Manipal Academy of Higher Education. As wearable health monitors, environmental sensor networks, and self-powered microdevices proliferate, the demand for materials that can store energy and sense their environment within the same printed footprint will only grow. This single-ink strategy, validated across three distinct device classes with quantified performance metrics, offers a compelling template for how multifunctional materials can compress device fabrication into a single, scalable printing step.

Subject of Research: A screen-printable multifunctional conductive ink based on tin cobalt oxide decorated carbon nanofibers for energy storage and sensing devices

Article Title: A single screen-printable multifunctional active ink platform based on tin cobalt oxide decorated carbon nanofibers for energy storage and sensing applications

Article References: Shetty, S., Saquib, M., M, S., & Nayak, R. (2026). A single screen-printable multifunctional active ink platform based on tin cobalt oxide decorated carbon nanofibers for energy storage and sensing applications. Advanced Composites and Hybrid Materials. https://doi.org/10.1007/s42114-026-02070-5

Image Credits: AI Generated

DOI: 10.1007/s42114-026-02070-5

Keywords: conductive ink, screen printing, tin cobalt oxide, carbon nanofibers, micro-supercapacitors, energy storage, humidity sensor, electrochemical sensor, naproxen detection, spinel oxide, printed electronics, sensors