Carbon Nanotube Nanocomposites Research Articles

Preparation and characterization of ball milled titanium oxide/multi walled carbon nanotube nanocomposite for supercapacitor applications

In this work, titanium oxide nanoparticles (TiO2 NPs) and TiO2-Multi walled carbon nanotubes (MWCNTs) nanocomposites were prepared using the ball milling technique. The characterization of synthesized nanocomposite was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), Raman spectroscopy, and transmission electron microscopy (TEM). Dielectric constant ε1 (ω) and dielectric loss ε2 (ω) were discussed in terms of the dielectric polarization process. The Ac conductivity was increased with increasing MWCNTs amount. The charge carrier transport mechanism was interpreted using the correlated barrier hopping model (CBH). The Impedance spectroscopy showed a non-Debye relaxation in the material. The specific capacitance was increased with increasing MWCNTs concentration. Based on these detailed results, the TiO2-MWCNTs nanocomposites displayed higher specific capacitance than TiO2. In addition, the control of the current density applied onto CV measurements and MWCNTs composition of the electrodes to enhance the capacitance will open up a new strategy for the high-performance supercapacitors.

Utility of Gold/Multiwalled Carbon Nanocomposite for Electrochemical Determination of Omarigliptin in Tablets and Human Plasma

Abstract An innovative voltammetric sensor was developed to estimate omarigliptin, a novel long-acting anti-diabetic drug. The sensor utilized a carbon paste electrode enhanced with a nanocomposite of carbon nanotubes and electrodeposited gold nanoparticles. The modified electrode was characterized using scanning electron microscopy and electrochemical impedance spectroscopy. The modification significantly improved the electrode's sensitivity and electrochemical efficiency and decreased its electron transfer resistance. The surface area of the modified electrode increased by about 2.8-fold compared to the bare electrode. Omarigliptin's oxidation behavior on the modified electrode was pH-dependent and irreversible, resulting in a peak current 4 times higher than the unmodified electrode. The modified electrode revealed good reproducibility, reusability, and stability. It allows for sensitive voltammetric analysis of omarigliptin over a linear range of 0.4–27 µM (LOD=0.12 µM) and good applicability in tablets and plasma. The recovery percentages are 98.47–101.27% in tablets and 95.86–105.02% in plasma. The modified electrode exhibits good selectivity towards OMR without interference from tablet excipients, endogenous plasma components, and co-administered drugs. The comparison with the reported methods reveals the superiority of the proposed method in terms of sensitivity, selectivity, applicability, and eco-friendliness. Finally, the proposed method demonstrates excellent environmental profiles based on recent assessment metrics.

Investigation of efficient adsorption-electrochemical degradation performance of ZIF-8/MWCNTs nanocomposites toward 2,4-dichlorophenol

The highly toxic and recalcitrant organic pollutant, 2,4-dichlorophenol (2,4-DCP), is commonly found in wastewater. Therefore, it is critical to investigate novel techniques for the efficient removal of 2,4-DCP from wastewater. The present study employed a one-step synthesis method to fabricate ZIF-8/multi-walled carbon nanotubes (ZIF-8/MWCNTs) nanocomposites with well-defined mesoporous structures, which were subsequently coated onto carbon cloth (CC) to form the anode ZIF-8/MWCNTs/CC. Subsequently, the adsorption performance of ZIF-8/MWCNTs toward 2,4-DCP and the adsorption-electrochemical degradation performance of ZIF-8/MWCNTs/CC toward 2,4-DCP were investigated. ZIF-8/MWCNTs exhibit exceptional adsorption capacity and rate toward the 2,4-DCP. At 303 K, it achieved a saturated adsorption amount as high as 1056.78 mg·g-1 within only 30 min of reaching equilibrium. Moreover, when coated on CC substrates, the internal pore structure of ZIF-8/MWCNTs is effectively exploited during the adsorption. In addition, the incorporation of MWCNTs enhances the conductivity of the ZIF-8/MWCNTs/CC electrodes, leading to reduced resistance and improved electron transfer rate. Notably, ZIF-8/MWCNTs/CC enabled complete removal of a 25 mg·L-1 solution of 2,4-DCP within only 90 min and a 50 mg·L-1 solution within 120 min. Furthermore, the degradation mechanism of 2,4-DCP was analyzed by means of DFT modeling theoretical calculations and intermediate product determination analysis, while evaluating the toxicity of the generated material was evaluated. This study provides improved solutions and strategies for the treatment of chlorophenolic compound pollution in wastewater.

A biosensor based on MWCNTs-BSA and TiO2-Laccase nanocomposite modified glassy carbon electrode for sensitive detection of luteolin in traditional Chinese Medicine

Luteolin (Lut) is an extractable natural flavonoid compound found in various herbs, vegetables, and fruits, and has become an increasingly important focus of in vivo and in vitro studies. These investigations confirmed that luteolin possesses antioxidant, antidiabetic, and anticancer properties, and has significant medicinal value. In this study, a biosensor was developed using a nanocomposite of Multi walled carbon nanotubes (MWCNTs), Bovine Serum Albumin (BSA), Laccase (Lac), TiO2, and Chitosan (Chi) to modify a glassy carbon electrode (GCE) for the detection of luteolin. The modified materials and electrodes were analyzed using scanning electron microscopy (SEM), cyclic voltammogram (CV), and electrochemical impedance spectroscopy (EIS). The square wave voltammetry (SWV) study indicated that the linear ranges were from 80 nM to 1 μM and from 1 to 6 μM, respectively, and the detection limit of luteolin was as low as 11 nM. The sensor exhibited excellent sensitivity and selectivity even in the presence of potential interfering substances. This proposed biosensor was successfully utilized to detect luteolin in the Traditional Chinese Medicine of Scutellaria Barbata and Dandelion. It demonstrated comparable good accuracy to traditional high performance liquid chromatography results. Therefore, this biosensor plays an important role in detecting the content of luteolin.

Synthesis and characterization of sheets like ZnO/MWCNT nanocomposites as a positive electrode material for asymmetric supercapacitor application

One practical approach to addressing the disparity between global energy needs and availability is through the advancement of effective energy storage systems, such as batteries and supercapacitors. These devices can store excess power and release it when demand surpasses supply, ensuring a stable energy flow. In the present work, the sheet-like ZnO/multi-walled carbon nanotubes (MWCNTs) nanocomposites were prepared by a simple hydrothermal method and used as positive electrode materials for supercapacitors. This investigation aims to design an effective electrode material for supercapacitors by harnessing the combined benefits of ZnO nanostructures and MWCNTs. The synergistic interaction between these materials is expected to significantly boost the electrode’s capabilities. The formation, crystal structural, morphological, elemental composition, and energy storage properties of prepared ZnO/MWCNTs electrodes were studied by various analytical methods (XRD, FTIR, TEM, XPS, CV, GCD, and EIS). The electrochemical performances of ZnO/MWCNTs electrode demonstrated specific capacitance (Cs) of 162.2 F/g at the current density of 2 A/g. The life cycle performances of prepared ZnO/MWCNTs electrode exhibited a 94 % after 2000 GCD cycles at 10A/g. The constructed ZnO/MWCNT//AC device attains a peak energy density of 19.50 W h/kg with a corresponding power density of 1280 W/kg.

Portable unibody semi-flow injection voltammetric sensor for on-site screening of illegal additive sibutramine in food supplements

In this study, a simple, portable, unibody semi-flow injection system was coupled with a screen-printed electrode (SFI/SPE) for the on-site electrochemical screening of sibutramine (SBM) in food supplements. The SFI was fabricated by laser engraving acrylic plastic and was attached to a modified SPE with double-sided adhesive tape. The SPE was modified with a nanocomposite of nitrogen-doped graphene nanoflakes and carbon nanotubes synthesized using hydrothermal and ultrasonic methods. The morphological structure and electrochemical properties of the nanocomposite were thoroughly investigated. The portable SFI-SPE sensing system was designed to be interfaced with a smartphone. Sample solutions can be continuously injected into the sensing system using a plastic syringe and SBM is determined by square wave anodic stripping voltammetry, controlled by means of a smartphone. The developed sensing system displayed linear ranges from 0.010 to 10 μg mL⁻1 and 10–60 μg mL⁻1 with an LOD of 0.0035 μg mL⁻1. The sensor delivered a response in a short time and demonstrated not only good reproducibility (RSDs ranging from 2.9 % to 4.9 % (n = 10)) and excellent resistance to interference but also high accuracy. The developed sensor was utilized for the screening and quantification of SBM in food supplements but the system could be used in a wider range of electrochemical (bio) sensor applications in the future.

Machine learning for nano-level defect detection in aligned random carbon nanotubes-reinforced electrically conductive nanocomposite

Machine learning allows fast nano-scale defect detection in polymer-impregnated aligned carbon nanotube (CNT) nanocomposites. Digital twins were populated by TEM-validated geometry; considered defects were flat cracks and close-to-spherical voids. Finite-element analysis of piezoresistive response was conducted by embedment of CNT network into matrix. Identification of a defect by change in CNT network piezoresistivity was challenged by: (1) randomness of CNTs’ shapes and placement, ML training happened on random realisations; (2) high strength of CNTs leading to the preservation of conductive paths along CNTs and changes only in conductivities of tunnelling contacts. “Artificial approximation“ was introduced to economise computer time multi-fold: ML was trained on cases with artificially degraded tunnelling conductivities within the defect. Three ML models: XGBoost, fully connected, and convolution neural networks were employed. All models managed the task for near-spherical voids, but performed poorly for flat cracks, due to the limited number of tunnelling contacts in crack volume. When trained on the mixed set of voids and cracks, both neural networks demonstrated the ability to learn the difference and detected even cracks, while XGBoost was not up to the challenge. By metrics, the convolutional neural network demonstrated the highest accuracy of predictions.

Efficient sensitive detection of nitrite with Binary Y/Fe-modified multiwalled carbon nanotube nanocomposite by electrochemical approaches

Low-dimensional metal nanoparticles (MNPs) intercalated with three-dimensional multiwalled carbon nanotube (MWCNT) materials may be combined to produce new nanocomposites for enhancing their chemical, structural, and morphological features. These composites have interesting physical and chemical characteristics that can be used in electrochemical sensing systems that work significantly well. This research presents a new method for detecting nitrite using an electrochemical sensor that utilizes a flat-electrode made of GCE fabricated by nanocomposite of MWCNTs intercalated with yttrium oxide (Y2O3) and iron oxide (Fe2O3) as Y/Fe-MWCNT at higher temperature. FT-IR, UV–vis., SEM, powder XRD, EDS, BET, and TEM were significantly used to characterize in detail the nanocomposite after its preparation by the solid-state chemical approach. Using CV, LSV, and EIS techniques, the electrochemical attributes of both the bare and Y/Fe-MWCNT fabricated electrodes (with the help of 5 % Nafion as conducting coating binder) were investigated. In addition, the linear relationship between nitrite concentration and peak current of LSV was seen between 1.0 and 1.6 M, with a lower limit of detection (LOD) of 0.027 M. When compared to modified electrodes with nitrite, the electrocatalytic behavior of the nanocomposite electrode is enhanced significantly. At applied potential window of −0.1 to +1.8 V, the Y/Fe-MWCNT sensor shows good selectivity even when there are a lot of interfering chemicals and metal ions. In addition, different PBS electrolyte solutions with pH values ranging from 6.5 to 8 were used to study the prepared sensor. The standard addition method was employed to detect the unidentified nitrite concentration in various real samples including sea water, industrial wastewater, and well water. It introduced a new route for the development of noble sensor probe with nanocomposite materials by electrochemical approach for the safety of environmental and health care field in a broad scale.

Preparation Of Modified Surfaces Based On Tannic Acid and Carbon Nanotubes and Investigation Of Their Electrochemical Properties

This study focuses on the electrochemical investigation of modifiers and their components that can provide the easiest and most sensitive results for electrochemical sensors. For this purpose, a nanocomposite of tannic acid and carbon nanotubes with extraordinary properties was obtained. The nanocomposite and its components were immobilized on glassy carbon electrode surfaces by the drop-drying technique. The morphological and electrochemical properties of the nanocomposite and its components were examined by scanning electron microscopy and cyclic voltammetry techniques. The surfaces modified with the nanocomposite and its components exhibited different electrochemical behaviors. Tests performed in ferricyanide, ferrocene, ruthenium hexamine (III) chloride, and ferricyanide/ferrocyanide probes showed that the nanocomposite-modified surface exhibited the best voltammetric behavior. Scan rate and pH studies showed that the nanocomposite-modified surface catalyzed electron transfer more and increased the active surface area.

Tailoring molecularly imprinted polymer on titanium-multiwalled carbon nanotube functionalized gold electrode for enhanced chlorophyll determination in microalgae health assessment.

A unique method for determining chlorophyll content in microalgae isdevised employing a gold interdigitated electrode (G-IDE) with a 10-µm gap, augmented by a nano-molecularly imprinted polymer (nano-MIP) and a titanium dioxide/multiwalled carbon nanotube (TiO2/MWCNT) nanocomposite. The nano-MIP, produced using chlorophyll template voids, successfully trapped chlorophyll, while the TiO2/MWCNT nanocomposite, synthesized by the sol-gel technique, exhibited a consistent distribution and anatase crystalline structure. The rebinding of procured chlorophyll powder, which was used as a template for nano-MIP synthesis, was identified with a high determination coefficient (R2 = 0.9857). By combining the TiO2/MWCNT nanocomposite with nano-MIP, the G-IDE sensing method achieved a slightly betterR2 value of 0.9892 for detecting chlorophyll in microalgae. The presented G-IDE sensor showed a significant threefold enhancement in chlorophyll detection compared withcommercially available chlorophyll powder. It had a detection limit of 0.917mL(v/v) and a linear range that spanned from10-6to 1mL. The effectiveness of the sensor in detecting chlorophyll in microalgae was confirmed through validation of its repeatability and reusability.

Physical properties of industrially produced carbon nanotube yarns for use in structural nanocomposites

Industrially-produced carbon nanotube (CNT) networks are a promising base for high-performance, continuous CNT nanocomposites, motivating widespread use in research and application development. Floating catalyst chemical vapor deposition (FCCVD) is a scalable, widely-adopted approach for synthesis of CNT networks; however, FCCVD can yield networks with organic impurities which complicate their characterization and processing. Herein, we analyze two varieties of FCCVD-synthesized commercial CNT yarn to explore the effects of densification and purification as they relate to forming infiltrated polymer composites. First, the fluid permeabilities and porosities of neat roving and chemically-stretched CNT yarns (CSYs) are estimated and compared to gas adsorption studies, which suggest high-tenacity CSYs are largely impermeable, leading to dry-core composites when polymer infiltration is attempted. Next, the presence and effects of oxygen-rich amorphous carbon impurities in the CSYs are identified and found to exist at the scale of CNT bundles, wherein the amorphous carbon behaves like a hygroscopic polymer matrix in a composite. Removal of the amorphous carbon phase in a 130%-increase in specific surface area, as quantified by BET analysis, and a statistically significant reduction in tensile properties. We discuss challenges in estimating yarn alignment and crystallinity resulting from these factors, and place our results in context of past studies analyzing intrinsic organic coatings in FCCVD-synthesized CNT networks.

Deep-Learning-Based Blood Glucose Detection Device Using Acetone Exhaled Breath Sensing Features of α-Fe2O3-MWCNT Nanocomposites.

Owing to the correlation between acetone in human's exhaled breath (EB) and blood glucose, the development of EB acetone gas-sensing devices is important for early diagnosis of diabetes diseases. In this article, a noninvasive blood glucose detection device through acetone sensing in EB, based on an α-Fe2O3-multiwalled carbon nanotube (MWCNT) nanocomposite, was successfully developed. Different amounts of α-Fe2O3 were added to the MWCNTs by a simple solution method. The optimized acetone gas sensor showed a response of 5.15 to 10 ppm acetone gas at 200 °C. Also, the fabricated sensor showed very good sensing properties even in an atmosphere with high relative humidity. Since the EB has high humidity, the proposed sensor is a promising device to exactly detect the amount of acetone in EB with high humidity. The sensor was powered by a 3200 mAh battery with the possibility of charging using mains electricity. To increase the reliability and calibration of the sensing device, a practical test was taken to detect acetone EB from 50 volunteers, and a deep learning algorithm (DLA) was used to detect the effect of various factors on the amount of acetone in each person's acetone EB. The proposed device with ±15 errors had almost 85% correct responses. Also, the proposed device had excellent response, short response time, good selectivity, and good repeatability, leading it to be a suitable candidate for noninvasive blood glucose sensing.

Atomic layer deposition of NiO-Coated CNT nanocomposites: Tailoring electrochemical properties for salivary lactate detection

NiO-coated stacked-cut carbon nanotubes (NiO/SCCNT) nanocomposites were synthesized via atomic layer deposition (ALD), coating the CNT core walls with a shell of NiO at different thickness varying NiO ALD cycles (0, 50, 200, and 700). The as-prepared core–shell composite nanomaterials were applied as electrode materials for modifying screen-printed carbon electrodes (SPCE) for the non-enzymatic electrochemical detection of lactate (LA). Electrochemical tests performed by CV and EIS demonstrated the reduced charge transfer resistance in NiO(x)/CNT-SPCE compared to pristine CNT-SPCE configuration, and the pronounced dependence of electrochemical behavior on NiO coating thickness. Notably, the NiO/CNT composite with 200 ALD cycles exhibited superior electrochemical properties for the electrooxidation of lactate. The developed sensor showed high sensitivity to LA, (138.44 µA mM−1 cm−2 in the 0–4 mM range). The limit of detection (LOD) values stood at 0.067 mM (considering the signal-to-noise ratio of S/N=3). The sensor showcased several advantages including a conductive supporting carbon material, impressive sensitivity, selectivity, stability, and reproducibility, thereby enabling rapid and precise lactate quantification in salivary real samples.

An efficient voltammetric sensing platform for trace determination of Norfloxacin based on nanoplate-like α-zirconium phosphate/carboxylated multiwalled carbon nanotube nanocomposites

Norfloxacin (NOR) residues pose a potential threat to our health and ecosystem, so it is highly urgent to develop a simple but accurate method for NOR determination. Therefore, an efficient voltammetric sensing platform was constructed for trace detection of NOR based on nanoplate-like α-zirconium phosphate/carboxylated multiwalled carbon nanotubes (α-ZrP/CMWCNT). The physiochemical characteristics of α-ZrP/CMWCNT were scrutinized using various microscopic, spectroscopic, and electrochemical means. In order to pursuit higher voltammetric responses, detection conditions of NOR such as accumulation potential, accumulation time and buffer pH, were explored comprehensibly. The α-ZrP/CMWCNT enlarged the electrochemically active surface area and lowered the charge transfer resistance. Owing to the synergistic interactions between nanoplate-like α-ZrP NPs and CMWCNTs, the α-ZrP/CMWCNT boosted the voltammetric response signals and reduced the over-potential of NOR. Consequently, the α-ZrP/CMWCNT demonstrated remarkably catalytic activity for NOR electrooxidation, with two broad linear detection ranges (0.01–0.1 μM; 0.1–10.0 μM) and a low detection limit (2.8 nM). The α-ZrP/CMWCNT modified glassy carbon electrode (GCE) exhibited strong anti-interfering ability even in excess of other antibiotics and common metal ions, and maintained robust response peaks up to two weeks. The α-ZrP/CMWCNT/GCE realized accurate determination of NOR from complicated matrices at trace levels with good recoveries (99.00–104.40 %).

Development and characterization of UV‐curable PCL/AESO/CNT nanocomposites for biomedical engineering

AbstractThis study investigates the development and characterization of UV‐curable Poly(ε‐caprolactone) (PCL), Acrylated Epoxidized Soybean Oil (AESO), and Carbon Nanotubes (CNT) nanocomposites for biomedical engineering applications. The PCL/AESO blends were prepared in various ratios, and CNTs were incorporated at concentrations of 0.5, 1.0, and 1.5 wt% to enhance mechanical properties. The UV‐curable formulations aimed to leverage rapid curing times, precise control over material properties, and the ability to fabricate complex structures. Results indicated that the incorporation of CNTs improved the tensile strength, modulus, and toughness of the composites. The PCL/AESO/CNT nanocomposites exhibited a tensile strength increase of 25%, a modulus improvement of 30%, and a toughness enhancement of 20% compared to pure PCL. Thermal analysis showed an increase in crystallization temperature and thermal stability, with a crystallinity degree of 63.31% and a maximum degradation temperature of 407°C for the B/C 50/50/1.5 sample. Biocompatibility assessments using L929 fibroblast cells revealed that the composites supported cell viability and proliferation over 7 days with negligible cytotoxicity. Cell attachment studies indicated favorable morphology and adherence, suggesting a conducive environment for cell growth and differentiation. Hydrolytic biodegradation studies demonstrated adjustable degradation rates, making these composites suitable for various biomedical applications requiring controlled biodegradation.

Novel application of carbon nanotube electrodes for electrochemical detection of amino acids in athlete’s biological samples

Understanding different physiological processes and spotting any health problems, especially in athletes, depend on tracking the quantities of amino acids in biological samples. This study looked at the creation of a unique electrochemical sensor for the sensitive and targeted identification of the necessary amino acid methionine in biological materials. Based on a modified glassy carbon electrode (GCE) surface, the sensor incorporated a tungsten disulfide (WS2) and carbon nanotube (CNT) nanocomposite. The improved electrical conductivity and catalytic activity of this material combination towards methionine oxidation led to its selection. The sensor that was created showed remarkable selectivity for methionine over other amino acids, along with a wide linear range of 5–1475 μM and a low detection limit of 10 nM. A relative standard deviation of 3.62 % was obtained across ten consecutive measurements, confirming the sensor's repeatability. The practical use of the CNTs-WS2/GCE sensor was verified by the detection of MTN in human blood serum, urine, and food samples. The recovery values ranged from 93.00 % to 99.40 %, and the relative standard deviation was less than 4.71 %. Based on these findings, we believe that our new CNTs-WS2/GCE sensor holds great potential for quick and precise methionine identification in biological samples from athletes.

Application of ultrasonic radiation for the development of polypropylene/multi-walled carbon nanotubes nanocomposites and its effect on the PP chemical degradation

Application of ultrasonic radiation for the development of polypropylene/multi-walled carbon nanotubes nanocomposites and its effect on the PP chemical degradation

Mussel-Inspired Multiwalled Carbon Nanotube Nanocomposite for Methyl Orange Removal: Adsorption and Regeneration Behaviors.

A mussel-inspired multiwalled carbon nanotube (MWCNT) nanocomposite (MWCNTs@CCh-PEI) was prepared by the co-deposition of catechol (CCh)/polyethyleneimine (PEI) and modification of MWCNTs for the efficient removal of methyl orange (MO). The effects of MO solution pH, contact time, initial MO concentration, and temperature on the adsorption capacity of MWCNTs@CCh-PEI were investigated. The results indicate that the adsorption capacity of MWCNTs@CCh-PEI was two times higher than that of pristine MWCNTs under the same conditions. The adsorption kinetics followed the pseudo-second-order model, suggesting that the adsorption process was chemisorption. The adsorption isotherm shows that the experimental data were fitted well with the Langmuir isotherm model, with a correlation coefficient of 0.9873, indicating that the adsorption process was monolayer adsorption. The theoretical maximum adsorption capacity was determined to be 400.00 mg·g-1. The adsorption thermodynamic data show that the adsorption process was exothermic and spontaneous. More importantly, the adsorption capacity of MWCNTs@CCh-PEI showed no significant decrease after eight reuse cycles. These results demonstrate that MWCNTs@CCh-PEI is expected to be an economical and efficient adsorbent for MO removal.

In Vivo Detection of Abscisic Acid in Tomato Leaves Based on a Disposable Stainless Steel Electrochemical Immunosensor.

Abscisic acid (ABA) plays an important regulatory role in plants. It is very critical to obtain the dynamic changes of ABA in situ for botanical research. Herein, coupled with paper-based analysis devices, electrochemical immunoelectrodes based on disposable stainless steels sheet were developed for ABA detection in plants in situ. The stainless steel sheets were modified with carbon cement, ferrocene-graphene oxide-multi walled carbon nanotubes nanocomposites, and ABA antibodies. The system can detect the ABA in the range of 1 nM to 100 μM, with a limit of detection of 100 pM. The ABA content in tomato leaves under high salinity was detected in situ. The trend of ABA changes was similar to the expression of SlNCED1 and SlNCED2. Overall, this study offers an approach for in situ detection of ABA in plants, which will help to study the regulation mechanism of ABA in plants and to promote the development of precision agriculture.

A Biosensor for Simultaneous Detection of Epinephrine and Ascorbic Acid Based on Fe(III)-Polyhistidine-Functionalized Multi-Wall Carbon Nanotube Composites.

Epinephrine (EP) is a very important chemical transmitter in the transmission of nerve impulses in the central nervous system of mammals. Ascorbic acid (AA) is considered to be the most important extracellular fluid antioxidant and has important antioxidant properties in the cell. In this study, a series of transition metal-polyhistidine-carboxylated multi-wall carbon nanotube nanocomposites were synthesized, and their simultaneous catalytic effects on epinephrine and ascorbic acid were investigated. The results showed that nanocomposites based on iron ions had the highest catalytic activity. The prepared biosensor expressed high selectivity toward EP and AA with LOD values of 0.1 μΜ (AA) and 0.01 μΜ (EP), and sensitivity values of 4.18 μA mM-1 with a range of 0.001-5 mM (AA), 50.98 μA mM-1 with a range of 0.2-100 μM (EP), and 265.75 μA mM-1 with a range of 0.1-1.0 mM (EP). Moreover, it showed good stability, good repeatability and high selectivity in real sample detection. This work is a reference for the design of new electrochemical enzyme-free biosensors and the detection of biomarkers.