Buckypaper Research Articles

NiFeCo-modified bucky paper electrodes for sensitive and selective uric acid detection

This study explores a convenient electroreduction-based method for developing ternary metallic alloy nanostructured self-supported buck paper electrodes (BPEs) for non-enzymatic uric acid (UA) detection. The impact of variable ratios of constituent nickel (Ni), iron (Fe), and cobalt (Co) elements on the nanostructured BPE’s electrochemical performance towards UA’s electrocatalytic oxidation was investigated. BPE’s innovative one-step electrochemical modificationwith trimetallic nanostructured alloys (NiFeCo) resulted in reproducible electrodes. The morphological and elemental composition analysis of the synthesized ternary metallic alloy nanostructured electrodes (NiFeCo/BPE) was performed using scanning electron microscopy and energy-dispersive X-ray spectroscopy, confirming the presence of Ni, Fe, and Co within the synthesized NiFeCo/BPE. The NiFeCo/BPE were comparatively evaluated against bimetallic alloy nanostructured electrodes (NiFe/BPE and NiCo/BPE). The resulting NiFeCo/BPE demonstrated a wider detection range of 10 µM to 1500 µM UA due to more electrochemical active sites when compared to the bimetallic nanostructured alloy electrodes. The NiFeCo/BPE demonstrated a sensitivity of 7.50 µAµM−1cm−2 with a detection limit of 5.02 µM towards UA. The fabricated self-supported NiFeCo/BPE sensor exhibited excellent selectivity in the presence of common interferents (e.g., ascorbic acid, dopamine, uric acid, glycine, fructose, and glucose). It showed promising utility in serum samples, with standard recoveries above 95.4 %. This study underscores the significance of uniform deposition of NiFeCo nanostructures, which is critical to unlocking the potential of bucky paper electrodes in developing flexible biosensors for broader range detection of uric acid without the need for enzymes.

High-Performance Dual-Redox-Mediator Supercapacitors Based on Buckypaper Electrodes and Hydrogel Polymer Electrolytes.

In recent years, the demand for solid, thin, and flexible energy storage devices has surged in modern consumer electronics, which require autonomy and long duration. In this context, hybrid supercapacitors have become strategic, and significant efforts are being made to develop cells with higher energy densities while preserving the power density of conventional supercapacitors. Motivated by these requirements, we report the development of a new high-performance dual-redox-mediator supercapacitor. In this study, cells were constructed using fully moldable buckypapers (BPs), composed of carbon nanotubes and cellulose nanofibers, as electrodes. We evaluated the compatibility of BPs with hydrogel polymer electrolytes, based on 1 mol L-1 H2SO4 and polyvinyl alcohol (PVA), supplemented with different redox species: methylene blue, indigo carmine, and hydroquinone. Solid cells were constructed containing two active redox species to maximize the specific capacity of each electrode. Considering the main results, the dual-redox-mediator supercapacitor exhibits high energy density of 32.0 Wh kg-1 (at 0.8 kW kg-1) and is capable of delivering 25.9 Wh kg-1 at high power demand (4.0 kW kg-1). Stability studies conducted over 10,000 galvanostatic cycles revealed that the PVA polymer matrix benefits the system by inhibiting the crossover of redox species within the cell.

Modulating the coordination environment and metal choice in carbon buckypapers supported metal phthalocyanines for enhanced electrocatalytic carbon dioxide reduction

In the search of versatile electrocatalysts for the electrochemical reduction of carbon dioxide (CO2RR), different transition metal phthalocyanines (MPc, where M=Fe, Co, Ni and Cu) have been immobilized by an easy and scalable wet impregnation on carbon nanotubes (CNTs) in the form of buckypaper (BP). Both the nature of the metal and the surface chemistry of the carbon support were found to play a pivotal role in determining their CO2RR efficiency and selectivity. We disclose here a potentiodynamic strategy for the controlled surface modification of BP with N- and P-containing polymeric species as a simple heterogenization strategy for molecular catalysts, enabling to easily tune their electrocatalytic performance. Syngas (mixture of H2 and CO) was obtained as the main product from CO2RR using FePc, CoPc and NiPc as electrocatalysts on functionalized (BPf) or non-modified BP. In contrast, CuPc was found to mainly catalyze the hydrogen evolution reaction (HER), with small amounts of formate as the only CO2RR product. It is possible to modulate the H2/CO ratio in the final product through the appropriate selection of the metal in MPc, the modification of the coordination environment by the controlled functionalization of the carbon support and the adjustment of the operating conditions. In particular, H2/CO ratios in a range between 0.17 and 1.28 have been obtained with good stability during electrolysis. Among all the MPc studied, CoPc surfaced as the most promising candidate for the reduction of CO2 to CO and H2 production, a finding substantiated by computational studies highlighting the positive impact of phosphate ligands on CoPc. This strategy outlines the starting line of a potential route toward the controlled generation of CO2RR-related products.

Impact of stacking sequence on the thermal and electrical properties of Poly (aryl ether ketone)/glassfiber/buckypaper composites

AbstractThe current market's imperative demand necessitates the research and development of advanced polymer composites, especially those incorporating nanofillers. Carbon nanotubes, in particular, have attracted significant attention within research and development for their potential in creating multifunctional composites. This study aims to evaluate the impact of incorporating carbon nanotube buckypapers (BP) on the thermal and electrical properties of poly (aryl ether ketone) (PAEK)/glass fiber (GF) composites. The BP was prepared through vacuum filtration and integrated into PAEK/GF composites with varying stacking sequences, followed by hot compression processing. The degradation behavior of the laminates was investigated using thermogravimetric analysis (TGA). The viscoelastic properties, evaluated by dynamic mechanical analysis (DMA), suggested an increase in stiffness with the inclusion of BP in two of the analyzed stacking sequences. Thermal conductivity, measured via the pulse laser method, showed results comparable to the base laminate (0.153 W/m·K). Meanwhile, electrical conductivity, assessed using the four‐point probe method in the in‐plane direction, revealed semiconductor properties, achieving a mean value of 3.162 S/cm for one of the samples, indicating electrical anisotropy within the multifunctional composite material.

Electrochemical Nicarbazin Analysis: Rapid Determination on Bucky Paper Disks Constructed from MWCNT

Nicarbazin, an anticoccidial drug, is a molecular complex comprising 4,4’-dinitrocarbanilide (DNC) and 2-hydroxy-4,6-dimethylpyrimidine (HDP) in a 1:1 molar ratio. The low solubility of DNC in water (below 0.02 mg L−1) necessitates the use of extraction methods for analysis. Traditional DNC determination methods are time consuming, and involve prolonged sample preparation, extraction procedures, and high costs,. This study presents the results of electrochemical analysis of DNC using an innovative electrode platform composed of bucky paper disks made from a blend of multi-walled carbon nanotubes (MWCNT) and polystyrene (MWCNT/PS/BP). The electroanalytical approach includes an initial adsorption stage of DNC on the electrode platform, followed by its subsequent reduction, capitalizing on the reducibility of the nitro groups within DNC. The analytical parameters of this method are favorable, featuring an average recovery value of 100.22 ± 7.87, a linear range of 2.011–15.112 mg·l−1, a sensitivity of 1.58 μA·mg−1 l−1, LOQ (limit of quantification) of 1.33 mg L−1, and LOD (limit of detection) of 0.40 mg·l−1.

Monitoring the damage evolution of Al 6061-T6 laser welded T-joint structure using nano-carbon tube based buckypaper film sensor

In this paper, buckypaper (BP) thin film sensor was used to monitor the health of Al 6061-T6 laser welded T-joint structure, including the strain and damage evolution of the joint during tension and bending. Al 6061-T6 T-joint was welded by laser welding technology. Laser welding technology of aluminum alloy is an advanced connection technology, which is of great significance for lightweight and efficient manufacturing of aerospace plate structure. BP sensor was prepared by using commercial multi-walled carbon nanotubes (MWCNTs) through dispersion, vacuum filtration and other processes. It has the advantages of simple manufacture, low cost, wide detection range and good stability. The experimental results indicate that the sensor has advantages such as high sensitivity, high stability, and repeatability. And the sensor can effectively monitor the strain and damage of the joint under tensile load. According to the resistance response of the sensor, three areas can be clearly identified, and joint damage can be predicted in advance. At the same time, sensors can also monitor the deformation of joints under bending, accurately reflecting the status of the joints.

Heat-Annealed Zinc Oxide on Flexible Carbon Nanotube Paper and Exposed to Gradient Light to Enhance Its Photoelectric Response.

Buckypaper (BP), a flexible and porous material, exhibits photovoltaic properties when exposed to light. In this study, we employed radio frequency (RF) sputtering of zinc oxide (ZnO) followed by rapid thermal annealing to enhance the photovoltaic response of BP. We investigated the impact of various sputtering parameters, such as the gas flow ratio of argon to oxygen and deposition time, on the morphology, composition, resistivity, and photovoltaic characteristics of ZnO-modified BP. Additionally, the photovoltaic performance of the samples under different illumination modes and wavelengths was compared. It was found that optimal sputtering conditions-argon to oxygen flow ratio of 1:2, deposition time of 20 min, and power of 100 watts-resulted in a ZnO film thickness of approximately 45 nanometers. After annealing at 400 °C for 10 min, the ZnO-modified BP demonstrated a significant increase in photocurrent and photovoltage, along with a reduction in resistivity, compared to unmodified BP. Moreover, under gradient illumination, the ZnO-modified BP exhibited a photovoltage enhancement of 14.70-fold and a photocurrent increase of 13.86-fold, compared to uniform illumination. Under blue light, it showed a higher photovoltaic response than under other colors. The enhancement in photovoltaic response is attributed to the formation of a Schottky junction between ZnO and BP, an increased carrier concentration gradient, and an expanded light absorption spectrum. Our results validate that ZnO sputtering followed by annealing is an effective method for modifying BP for photovoltaic applications such as solar cells and photodetectors.

Flexible and stretchable high performance enzymatic biofuel cells implantable in tube-type artificial blood vessel kit

Enzymatic biofuel cells (EBFCs) are emerged as promising power sources for implantable devices, offering excellent form factor and performance. For these applications, EBFCs require customer tailored structure and more than 10 μW power. In this study, flexible and stretchable EBFCs are suggested, assessing their performance using tube-type artificial blood vessel (TABV) cell kit with sheep blood fuel. To fabricate the EBFCs, buckypaper (BP) is molded to polydimethylsiloxane (PDMS) to fabricate BP@PDMS electrode that shows excellent strain rate (95 %) and durability (1500 cycles) in tensile and fatigue tests. Additionally, electrochemical evaluations are implemented to measure the performance of anode and cathode fabricated with BP@PDMS. In anode including 1,10-phenanthroline-5,6-dione and glucose dehydrogenase, maximum reactivity of glucose oxidation is 1.05 mA/cm2, while in cathode including bilirubin oxidase, that of oxygen reduction is 0.61 mA/cm2. Regarding flexibility, anode and cathode are little affected by current density irrespective of bending angle, proving that the fabricated anode and cathode have good flexibility. To emulate the behavior of EBFCs in actual blood vessel, EBFCs are implanted in TABV cell kit, fueling sheep blood. Observed open circuit voltage of 0.59 V and maximum power of 26 μW reveals that fabricated EBFCs have superior potential to be considered as power sources for implantable devices.

Tailoring Interfaces of All-Carbon Electromagnetic Interference Shielding Materials for Boosting Comprehensive Performance.

Electromagnetic interference (EMI) shielding materials with lightweight, high shielding effectiveness, excellent chemical stability, especially minimized secondary electromagnetic pollution, are urgently desired for integrated electronic systems operating in harsh working environments. Here in this study, by systematically engineering and matching the interfacial properties of carbon-based membrane materials, i.e., graphite paper, whisker carbon nanotube paper (WCNT paper), carbon nanotube film (CNT film), bucky paper (BP), and carbon cloth (CC) with three-dimensional (3D) porous carbon nanotube sponge (CNTS), we successfully constructed a series of multifunctional all-carbon EMI shielding materials, which exhibit excellent average shielding effectiveness of over 90 dB with a thickness of about 1 mm and dramatically minimized secondary electromagnetic reflection. Moreover, benefiting from the all-carbon nature and engineered interfaces, our CMC materials also exhibit excellent photothermal and Joule heating performances. These results not only provide guidance for designing advanced multifunctional all-carbon EMI shielding materials but also shed light on the hidden mechanism between interfaces and performances of composite materials.

A single carbon nanotube-entangled high-performance buckypaper with tunable fracture mode.

It is well known that the traditional buckypaper (BP) is composed of a certain number of short carbon nanotubes (CNTs) intertwined with each other and sliding always happens when the BP is under tensile and impact loading, which results in inferior mechanical properties compared to single CNTs. In this work, a highly-entangled single-wire BP (SWBP) structure is constructed by a modified self-avoiding random walk approach. The in-plane mechanical properties and impacting behaviors of the SWBPs with different entanglement degrees and interface frictions are systematically investigated via newly developed coarse-grained molecular dynamics (CGMD) simulation. A coarse-grained method can effectively reflect the inter-tube van der Waals (vdW) interactions and the mechanical behaviors of CNTs, including tension, bending and adhesion. In this work, from the tensile simulations of the SWBP, the results showed that the self-locking mechanism between entangled CNTs could significantly enhance the tensile resistance of the film. Besides, the mechanical properties of the SWBP are highly dependent on the entanglement degree and the interface friction between CNTs. Furthermore, two distinct fracture modes, ductile fracture and brittle fracture, are revealed, which can be efficiently controlled by changing the related friction between CNTs. From the impacting simulations, it is found that the impacting performance can be effectively tuned by adjusting the entanglement degree of the film. In addition, the kinetic energy of the projectile could be rapidly dissipated through the stretching and bending of CNTs in the SWBP. This work provides an in-depth understanding of the effect of interface friction and entanglement degree on the mechanical properties of the buckypaper and provides a reference for the preparation of strong CNT-based micromaterials.

Flexible Manganese Oxide Electrode Fabricated with Heat‐Treated Buckypaper for Supercapacitor

With the emergence of new technologies, wearable and portable devices become essential tools for various applications, which are flexibly designed. In this situation, flexible supercapacitors with fast charge and discharge cycles are needed as their power source. This study introduces the flexible pseudocapacitor electrode fabricated by electrodeposition of manganese oxide (MnO2) onto heat‐treated hydrophilic buckypaper (BP) molded on polydimethylsiloxane (PDMS). Here, the heat treatment of BP that is optimized by a proper adoption of thermogravimetric analysis is performed to enhance the electrodeposition efficiency of MnO2. Then, proper hydrophilicity of the heat‐treated BP (H‐BP) and successful preparation of MnO2/H‐BP@PDMS electrode is well confirmed by electrochemical, spectroscopical, and optical measurements. In their evaluations, it is found that heat treatment of BP is more important factor than electrodeposition time to improve the electrodeposition efficiency of MnO2 under the same aqueous electrolyte. With that, such optimally prepared MnO2/H‐BP@PDMS electrode shows a high electrical double layer and excellent specific capacitance of 1.31 F/cm2 at 1 mA/cm2, which are better results than those of other electrodes.

Mechanical and electrochemical properties of carbon nanotubule-polyaniline nanowire/polyaniline nanoparticle high-strength ultra-flexible aerogel buckypaper

The carbon nanotube-polyaniline nanowire/polyaniline nanoparticle (CNT-PANInw/PANInp) aerogel buckypaper (BP) was constructed, where PANI nanoparticles were uniformly embedded into the CNT network, and a series of downhanging PANI nanowires were grown in situ on the CNT monofilaments. The aerogel BP with 80 µm thickness had a PANI load of 3.5 mg/cm2 and a porosity of 69%. The cross-junctions between CNT monofilaments were anchored by polyvinyl alcohol gel. It had a tensile strength of 25 MPa, with a strain of 11.4%, being folded along sharp creases or violently rubbed without damage. The specific capacitance of the aerogel BP electrode decreased from 3.070 to 2.064 F/cm2, as the current density increased from 2 to 8 mA/cm2, with a capacitance retention of 67.2%. Its specific capacitance was 1.720 and 1.560 F/cm2 after 2000 folding in halfunfolding and 200 zigzag foldingunfolding cycles, respectively, with the capacitance retention of 84.0% and 76.2%, at 8 mA/cm2. Its specific capacitance was 1.832 and 1.224 F/cm2 after 2000 and 10,000 charge-discharge cycles, respectively, with the capacitance retention of 88.8% and 59.3%, at 8 mA/cm2. Its residual specific capacitance after 10,000 cycles was higher than most of the reported initial value of the materials with similar compositions.

Exploring novel electroanalytical approach using MWCNT nanostructures to quantify nimodipine

A new type of buckypaper of MWCNT with entrapped Nimodipine (NMD) drug was constructed. NMD features a nitroaromatic group that is electroreducible, and a dihydropyridine ring that can be electrooxidized. From the perspective of the nitroaromatic group's reductive capability, we have devised amperometric and voltammetric analytical strategies, including both differential pulse and linear voltammetric techniques. These methods are implemented using glassy carbon electrodes (GCE) modified with buckypaper (BP) disks composed of multiwalled carbon nanotubes (MWCNT), which are capable of adsorbing NMD. Furthermore, by capitalizing on the oxidative capacity of the dihydropyridine ring, we have designed strategies that involve amperometry using screen-printed electrodes (SPE) modified with BP-MWCNT mini discs within a Batch Injection Analysis Cell (BIAS) designed for SPE. The developed sensor was applied successfully to determine the drug in commercial tablets. The analytical parameters of this sensor were adequate, with a recovery value of 98.24 % and detection and quantification limits of 7.01 mgL−1 and 23.35 mgL−1, respectively using the DPV method.

Carbon Nanotube-Polyurethane Composite Sheets for Flexible Thermoelectric Materials.

Integration of single-wall carbon nanotubes (SWCNTs) in the form of fabriclike sheets or other preformed assemblies (films, fibers, etc.) simplifies their handling and allows for composites with higher nanotube contents, which is needed to better exploit their outstanding properties and achieve multifunctional materials with improved performance. Here, we show the development of p-type SWCNT-thermoplastic polyurethane (TPU) fabric materials with a wide range of SWCNT contents (from 5 to 90 wt %) by employing a one-step filtration method using a suspension of SWCNTs in a TPU solvent/nonsolvent mixture. The mechanical and thermoelectric (TE) properties of these SWCNT-TPU nanocomposites were tailored by varying the SWCNT/TPU wt % ratio, achieving significant advantages relative to the pristine SWCNT buckypaper (BP) sheets in terms of strength and stretchability. In particular, the SWCNT-TPU nanocomposite with a 50/50 wt % ratio composition (equivalent to 15 vol % of SWCNTs) shows a power factor (PF) of 57 μW m-1 K-2, slightly higher compared to the PF of the SWCNT BP prepared under the same conditions (54 μW m-1 K-2), while its mechanical properties significantly increased (e.g., ∼7-, 25-, and 250-fold improvements in stiffness, strength, and tensile toughness, respectively). These results represent a significant step toward the development of easy-to-process self-supporting and stretchable materials with robust mechanical properties for flexible thermoelectric devices.

Does carbon nanotube buckypaper affect mode-I and II interlaminar fracture toughness under quasi-static loading?

Carbon fiber reinforced polymer (CFRP) composites are widely used to produce structural components. However, their low interlaminar strength makes them susceptible to delamination, limiting structural applications. Aiming to solve this problem, this work proposes adding carbon nanotubes buckypaper (BP) into CFR thermoplastic composites as an interlayer to enhance the interlaminar strength through the BP bridging effect. Despite this objective, the carbon nanotube BP changed the delamination behavior in mode-I, creating an easy pathway for crack growth (smooth fracture surface) and reducing the interlaminar strength. An opposite behavior was observed for mode-II, in which BP acted as an obstacle for crack growth through the shear direction due BP bridging effect, which slightly improved interlaminar strength, resulting in a rougher surface. The experiments demonstrated through the energy involved in crack growth, the roughness of the fracture surface, and the amount of fracture mechanisms when BP was incorporated that in mode-I the delamination strength decreased, while it increased under the shear mode. This evidences that the BP bridging effect is influenced by the loading mode. Finally, this work highlights the need to study individual modes I and II in composites with buckypaper as an interlayer, since it influences the interlaminar toughness differently.

Removal of Antibiotics from Wastewaters by Carbon Nanotube Filtration Membrane: A Review

Water pollution by antibiotics is a global challenge requiring an affordable, readily available, efficient solution. Therefore, this review evaluates the role of carbon nanotube (CNT) based filtration membrane as an efficient solution to provide clean water free of antibiotic residues. The study considered the preparation of CNTs and CNT filtration membranes and their performance towards removing antibiotics from water. The study revealed that there are several methods for the preparation of CNTs, among which the chemical vapour deposition (CVD) is commonly used. It further revealed that three types of CNT-based membranes exist, which are vertically aligned (VA-CNT), bucky paper CNTs (BP-CNT) and CNT-based composite (CNT-CPS). Despite the high performance demonstrated by the membranes, there is a need to evaluate the cost-effectiveness, safety, and regeneration of the membranes. More studies are also required on a large scale to understand the behaviour of the membranes in the purification of ample water supply and the effect of interference from other co-pollutants in water in the real-life polluted water matrix. The study showed that CNT-based filtration membranes are promising membranes for the future, with reliable properties for effectively purifying contaminated water.

Experimental studies on carbon nanotube strain sensors

Conventional metal foil strain sensors only measure strain on the structural surface in predetermined directions and locations. These are made of Nichrome (Ni-Cr alloy) and Constantan (Cu-Ni alloy) and have gauge factor of 2. A carbon nanotube (CNT) as a strain sensing material is gaining research interest due to its outstanding electrical and mechanical properties. These sensors apart from multidirectional sensing are capable of making additional contributions such as structure strengthening or structure damping. Bucky paper (BP) alternatively called CNT film or CNT network made from single-walled carbon nanotube or multiwalled carbon nanotubes (SWCNT or MWCNT) has been used by some researchers in the past as strain sensor. However, they have observed nonlinear relationship between strain and change in resistance, and lower gauge factor. Literature review in the field indicates that there is scope for improvement in the performance of Bucky paper-based strain sensors. The objective of this experimental work is to investigate effect of CNT film constituents (MWCNT, SWCNT and mix of both), purification of CNTs and effect of preparation method on sensitivity. The work involves preparation of film from CNTs by vacuum filtration method and preparing the strain sensors from the same. These sensors are loaded along with conventional foil strain gauges on opposite side. The change in resistance of sensor due to applied load is measured to evaluate sensitivity or gauge factor of sensor for various cases. It was observed that the sensitivity of CNT strain sensor is dependent on the preparation and purification methods as well as on the aspect ratio.

Paper-type membraneless enzymatic biofuel cells using a new biocathode consisting of flexible buckypaper electrode and bilirubin oxidase based catalyst modified by electrografting

A new biocathode consisting of bilirubin oxidase (BOD), 4-aminophthalic acid (4-APA) and buckypaper (BP) electrode is suggested for enzymatic biofuel cells (EBFCs). Here, to enhance the electron transfer rate of BOD, electrografting method is imported. When this method and 4-APA are utilized, BP surface has negative charges by the polarity arrangement of 4-APA, forming BP/4-APA structure. With the modification of surface charge, T1 active site within BODs having positive charges are strongly bonded with the negative charges of BP/4-APA in neutral pH condition, while the orientation of T1 site is well aligned by electrostatic interaction. This treatment increases both reactivities of cathodic reaction and EBFC performance. To prove that, the performance of membraneless paper-type EBFCs using the new flexible BP/4-APA/BOD biocathode is investigated. According to the evaluations, their maximum power density and open circuit voltage are 92.025 ± 0.892 μW cm−2 and 0.612 ± 0.002 V with injection of 10 mM glucose which is a condition of living body fluid. Such performances are far better than those of other membraneless EBFCs and are large enough to be utilized as a power source of implantable devices for the human body.

Highly Permeable Bucky Paper for the Gas Diffusion Layer of Fuel Cell Prepared by a Whole‐Process Solid Template Method

Due to the control of porosity and pore size on mass transfer, the structure of the gas diffusion layer (GDL) has a critical impact on the performance of fuel cells. The bucky paper has high conductivity and abundant pores, which has potential to be used as GDL in fuel cells. Herein, a whole‐process solid template method is used to prepare the bucky paper with microcrystalline cellulose (MCC), whose porosity and pore size can be regulated quantitatively. The bucky paper with MCC as a pore‐forming agent has more larger pores, and these pores are mostly connected, which meet the needs of fuel cell application. The result of gas flux shows that the permeability of the bucky paper increases from the initial 12 to 240 mL min−1 kPa−1 cm−2 with MCC. The pore structure of bucky paper are significantly improved, so that the bucky paper with MCC leads to a higher fuel cell power density. Furthermore, the impedance result presents that with the addition of MCC, the mass transfer resistance of the fuel cells decreases significantly. It is fully supported in these results that MCC can modify the pores of the bucky paper and applied in proton exchange membrane fuel cells well.

Electrochemical characterization of nitrocoumarin-modified nanostructured electrode platforms: New precursors for the electrocatalysis of NADH

All synthesized nitrocoumarins, 3-acetyl-6-nitrocoumarin 6-Coum, 3-(3-nitrocinnamoyl)-coumarin 3-CinCoum, 3-(4-nitrocinnamoyl)-coumarin 4-CinCoum, and 3-(4-nitrocinnamoyl)-6-nitrocoumarin 4-Cin-6-Coum, were used to generate novel nanostructured multiwalled carbon nanotube (MWCNT) electrode platforms that were electrochemically activatable to generate the redox pair ArNHOH/ArNO. This redox pair is capable of acting as a mediator in electrocatalysis of NADH oxidation.Nitrocoumarin-modified nanostructured electrode platforms were prepared using both drop casting and buckypaper (BP) methods for comparative purposes, and they showed no differences in their electrochemical responses.It was observed that the compound most easily reduced was 4-Cin-6-Coum. The reduction occurred first at the 4-nitrocinnamoyl group due to the withdrawing electron effect exerted by the cinnamoyl carbonyl group.The heterogeneous transfer rate constant, kh, was calculated for all of the redox mediators, and they decreased in the order 4-CinCoum> 3-CinCoum> 6-Coum> 4-Cin-6-Coum (II). On the other hand, we observed no significant differences for retention of the redox pairs ArNHOH/ArNO from the nitrocoumarin precursor compounds on the electrode, and the retention values ranged from 79.6 to 91.6% after one hour of working with the nanostructured electrodes.With this electrocatalytic response, it is possible to develop an amperometric sensor for the determination of NADH that includes nanostructured platforms with nitrocoumarins. We obtained LODs of 2.95 µM and 3.43 µM for 6-Coum and 4-Cin-6-Coum (II), respectively.