Nitrogen-doped Graphene Nanosheets Research Articles

Cobalt nanoclusters Deposit on Nitrogen-Doped graphene Sheets as bifunctional electrocatalysts for high performance lithium – Oxygen batteries

Rechargeable lithium-oxygen (Li-O2) batteries are being considered as the next-generation energy storage systems due to their higher theoretical energy density. However, the practical application of Li-O2 batteries is hindered by slow kinetics and the formation of side products during the oxygen reduction and evolution reactions on the cathode. These reactions lead to high overpotentials during charging and discharging. To address these challenges, we propose a simple ultrasonic method for synthesizing cobalt nanoclusters embedded in nitrogen-doped graphene nanosheets (GrZnCo) derived from metal-organic frameworks (MOFs). The resulting material, due to the retention of metallic cobalt structure, exhibits better electronic conductivity. Additionally, the GrZnCo catalyst shows vigorous catalytic activity, which can improve reaction kinetics and suppress side reactions, thus lowering the charging overpotential. We have investigated the impact of different catalyst compositions (GrZnCox; x = 1, 3, 5) by varying the amounts of cobalt and zinc. The optimum catalyst, GrZnCo3, contains high cobalt-N active components, graphitic-N, pyridinic-N, pyrrolic-N, and abundant defect structures, which enhance the electrochemical performance. The defect-rich GrZnCo3 catalyst enables Li-O2 batteries to achieve a high discharge capacity of 13500 mAh·g−1 at 50 mA·g−1 and a remarkable long-term cycling performance of over 400 cycles at 100 mA·g−1 with a limited capacity of 500 mAh·g−1. This work demonstrates an effective approach to fabricate cost-effective electrocatalysts for various energy storage systems.

Design and fabrication of nitrogen-doped graphene-promoted Na3MnTi(PO4)3@C cathode with three-electron reactions for sodium-ion storage

As a novel cathode material for sodium-ion batteries, Na3MnTi(PO4)3 (denoted as NMTP) has received great attention because of its abundant natural resources, excellent safety, low toxicity as well as three-electron reactions. Unfortunately, the pure NMTP cathode displays a bad conductivity, resulting in an inferior electrochemical performance for sodium energy storage. Herein, we introduce a good route to fabricate the nitrogen-doped graphene-decorated NMTP@C (denoted as NG-NMTP@C) composite with superior rate property and superior cycle stability for the first time. In this fabricated material, the nitrogen-doped graphene nanosheets are dispersed into the NMTP@C particles. Compared to NMTP@C, the prepared NG-NMTP@C cathode possesses better cycle stability and higher capacity. It shows the capacity of 173.1 mAh g−1 at 0.1 C and presents the high capacity retention of around 97.1 % at 10.0 C over 400 cycles. Therefore, this fabricated NG-NMTP@C nanocomposite can be employed as the novel positive electrode in sodium-ion storage.

One-pot synthesis of tungsten oxynitride/nitrogen-doped graphene with particle-sheet hybrid nanostructure as a highly effective binder-free supercapacitor electrode

High-performance nanoscale composites have achieved predominance as promising materials for supercapacitor applications. Graphene nanosheets decorated with transition metal oxynitride nanoparticles can be highly beneficial in improving supercapacitor properties. However, they are hardly retrieved, and their electrochemical characterizations and inherent charge-storage mechanisms have not been deeply investigated. Herein, tungsten oxynitride decorated nitrogen-doped graphene (WON-NG) is synthesized by a facile one-pot strategy in a particle-sheet hybrid nanostructure. The nanocomposite is grown directly on a nickel foam (NF) as the current collector through the synthesis process. X-ray photoelectron spectroscopy and TEM images have confirmed the particle-sheet hybrid nanostructure of the prepared nanocomposite with tungsten oxynitride nanoparticles and nitrogen-doped graphene nanosheet. The oxygen and nitrogen-based redox groups, which synergistically coexist in the hybrid network, inherently cooperate in the electrochemical activities of the nanocomposite. The electrochemical measurements show that the WON-NG|NF electrode can deliver a superior specific capacitance of 1079.4 F g−1 (4.6 F cm−2) at 1 A g−1 in 1 M KOH aqueous electrolyte. In-depth investigations suggest that the diffusive-controlled process governs the charge storage mechanism at all scan rates in the composite for the advantageous porous morphology. The assembled all-solid-state asymmetric supercapacitor device exhibits a high energy density of 81.6 Wh kg−1 and a power density of 5005.4 W kg−1. Also, the designed devise shows an excellent cycle life with 87.7% capacitance retention of 10,000 cycles.

Electrochemical activity of self-supporting nitrogen-doped graphene for the degradation and in-situ determination of methylene blue

Environmentally friendly wastewater treatment and online pollution monitoring systems, important for water quality control, are yet to be developed. Electrochemical strategies combining the electrocatalytic degradation and electroanalysis of organic pollutants are expected to achieve this key technology. This study employed a chemical vapor deposition method using N₂ gas as the nitrogen source and applying an alternating electric field to prepare self-supporting nitrogen-doped graphene (NG) tubes with a wall thickness of up to 480 μm comprising few-layer NG nanosheets. The correlation between the properties of these materials and the electrocatalytic activity for methylene blue (MB) was investigated. The feasibility of the electrochemical strategy for online wastewater treatment and detection was validated using a combination of UV–visible spectroscopy and differential pulse voltammetry. The NG tube with the N-C bond distribution regulated by adjusting the methane flow rate and growth time exhibited high electrocatalytic activity, rapidly degrading 50 mg L⁻¹ of MB within 36 min and tracking changes in MB concentration. The NG tubes were assembled in an electrocatalytic meter pen for water treatment, achieving a degradation efficiency of 99.4 % and a detection limit of 0.3 mg L−1 for the MB solution, quite satisfactory for emerging simultaneous degradation and monitoring processes. The developed self-supporting NG tubes are promising materials for electrocatalytic degradation anodes and sensing electrodes in water treatment. Dual-functional electrocatalytic systems have potential applications in water quality monitoring and improvement.

A facile and efficient voltammetric sensor for marbofloxacin detection based on zirconium-based metal-organic framework UiO-66/nitrogen-doped graphene nanocomposite

Improper and persistent use of marbofloxacin (MAR) is prone to produce residues that deteriorate the surrounding environment and endanger our health. Hence, it is urgent to stablish a facile and efficient detection technique for the detection of MAR. Herein, a highly efficient electrochemical platform was constructed for sensitive determination of MAR using zirconium-based metal–organic framework (UiO-66)/nitrogen-doped graphene (NG) nanocomposites (UiO-66/NG). The surface morphology, crystalline phase, elemental composition, and electrochemical behavior of UiO-66/NG were characterized by various spectroscopic and electrochemical techniques. Owing to the synergistic interaction of UiO-66 MOFs and NG nanosheets, the UiO-66/NG exhibited remarkable catalytic activity for MAR oxidation. As consequently, the UiO-66/NG demonstrated a wide linear response range (0.01 − 10 μM), high sensitivity (1.80 μM μA−1 cm−2) and low detection limit (0.002 μM). The proposed UiO-66/NG/GCE demonstrated robust voltammetric responses even in the presence of excess potential interfering species and retained stable response signals for at least two weeks. More importantly, the proposed UiO-66/NG/GCE displayed highly consistent sensitivity toward MAR detection in both aquaculture water and milk matrices and PBS buffer, and achieved accurate and sensitive detection of MAR with good recovery. Together with its low cost and facile operation, the UiO-66/NG/GCE shows great prospects for trace detection of MAR from complex matrices.

Machine Learning-Assisted design of boron and nitrogen doped graphene nanosheets with tailored thermomechanical properties

Doping graphene with boron and/or nitrogen enhances its potential for various applications, such as electronics and energy devices. However, these modifications impact the material's properties, influencing its response to external forces, temperature, and heating. Investigating the connection between the structure of co-doped graphene nanosheets and their thermomechanical properties is crucial for accurate predictions and tailored nanosheet engineering. In the present study, molecular dynamics (MD) simulations were performed to compute the thermal and mechanical properties of 300 randomly generated boron/nitrogen co-doped graphene nanosheets with doping concentrations in the range of 0%-15%. Next, the obtained MD results were used to train, tune, and validate a wide spectrum of supervised machine learning models, including linear regression models, regression trees, support vector machines, Gaussian process regression models, kernel approximation models, ensembles of regression trees, and regression neural networks. Our aim is to find models that better estimate, without overfitting, the structure-properties relation of boron/nitrogen co-doped nanosheets. To this end, the models with the highest coefficient of determination (R2) and the lowest root mean square error (RMSE) were utilized. Finally, an appropriate implementation of guided random search algorithms, mainly Genetic Algorithms, was used to solve the inverse problem, i.e., find the nanosheet structure which exhibits the desired set of property values. To this end, thermal conductivity, Young’s modulus, failure stress, and failure strain were specified as target values. A detailed comparison between the employed models and their validation via MD simulations is also included. The achieved results provide sufficient evidence of the accuracy and viability of the applied procedure in both prediction of thermomechanical properties as well as identification of structures with desired properties. This study provides a roadmap that could help scientists and engineers develop nanosheets-based materials with tunable thermomechanical properties, ultimately leading to the creation of innovative and high-performance technologies.

3D binder-free nanoarchitecture design of porous silicon/graphene fibers for ultrastable lithium storage

Enhancing the stability and fast-charging capability of battery electrodes is of paramount importance in the field of battery technology. Silicon (Si), renowned for its high specific capacity, has emerged as a promising candidate for anodes. However, the limited structural stability and electron/ion conductivity of silicon-based anodes have raised significant concerns, including fractures and the continuous formation of unstable solid-electrolyte interphase (SEI) layers, leading to rapid capacity decay. In this study, we introduce a comprehensive approach to fabricating a binder-free and free-standing anode electrode paper using a combination technique of employing electrospinning, magnetron sputtering, and chemical vapor deposition (CVD) techniques. This developed paper electrode incorporates a 3D interconnected network of nitrogen-doped vertical graphene nanosheets (VGs) that connect porous carbon fibers (PCFs) with uniformly distributed Si nanoparticles (VGs@Si@PCFs). The as-fabricated VGs@Si@PCFs paper effectively addresses the mechanical and chemical stability issues commonly associated with Si anodes. The VGs@Si@PCFs anode demonstrates a remarkable reversible capacity of 2205 mAh g-1 at 0.1 A g-1 and exhibits exceptional cycling performance with 83.5% capacity retention at 1.0 A g-1 after 3000 cycles. This design leverages the nanoporous carbon fibers and nitrogen-doped vertical graphene nanosheets as flexible and conductive supports, enhancing the robustness and flexibility of the electrode. Additionally, mechanical modeling reveals that the overall Mises strain in the porous VGs@Si@PCFs structure is significantly lower compared to nonporous cases, potentially minimizing low-cycle fatigue. Our free-standing Si/C composite anode introduces a new class of low-strain Si-based materials, showcasing significantly improved stabilities and fast-charging capabilities.

Synthesis of new Pd@NDG electrocatalyst by using g-C3N4/GO hydrogel toward formic acid electrooxidation reaction in direct formic acid fuel cell

In this research, the new Pd@NDG electrocatalyst was evaluated for the formic acid oxidation reaction. The nitrogen-doped graphene nanosheets (NDG) support was obtained by heating the g-C3N4/GO hydrogel in an inert atmosphere. The Pd@NDG electrocatalyst was prepared by combined use of NDG and palladium chloride via a one-stage reduction using ascorbic acid. The as-prepared Pd@NDG electrocatalyst displayed high catalytic activity in formic acid oxidation. The significant electrocatalytic performance stems from the presence of the NDG support in the structure of the electrocatalyst. The NDG support improved the physicochemical properties of the catalyst. The NDG support acts as an excellent ligand and leads to increase dispersion of Pd. The number of active metal sites is enhanced by increasing dispersion and exposing the surface area of the electrocatalyst and improving electronic properties, which lead to improving the catalytic performance of the catalyst. Furthermore, the formic acid electrocatalytic activity and the durability of Pd@NDG electrocatalyst as compared to the Pd/C commercial benchmark catalyst. The results displayed that the Pd@NDG electrocatalyst has better performance for formic acid oxidation.

Comparing Pt electrodeposition processes on nitrogen-doped graphene nanosheets for the electroreduction of oxygen

Comparing Pt electrodeposition processes on nitrogen-doped graphene nanosheets for the electroreduction of oxygen

Theoretical insights into heteronuclear dual metals on non-metal doped graphene for nitrogen reduction reaction

Electrochemical nitrogen reduction reaction (eNRR) is a promising strategy for sustainable ammonia production. To achieve high yield and energy efficiency, single-atom dispersion on nitrogen-doped graphene nanosheets has been extensively explored as an electrocatalyst for eNRR. However, challenges remain owing to the high overpotentials arising from unitary active sites and unabundant ligands. In this study, heteronuclear dual-metal catalysts with different non-metals doped in a graphene frame were computationally designed. After a two-step scanning based on density functional theory calculations, five candidates, namely FeMo-S, RuMo-B, RuMo-P, RuMo-S, and RuW-S, were identified as promising catalysts with calculated onset potentials of –0.18, –0.25, –0.27, –0.29, and –0.24 V, respectively. These catalysts can also effectively suppress the competitive hydrogen evolution reaction during NRR. Such excellent catalytic performance origins from two synergetic effects: (1) the cooperation of heteronuclear metals contribute to the electron transfer from active sites to the anti-bonding orbitals of N2 molecules adsorbed on catalysts to effectively activate N≡N bonds; (2) metal-ligands (non-metals) interactions moderate the binding strength of intermediates to slab, which is one of reasons for low NRR onset potential and high NH3 selectivity. The present study provides a theoretical understanding of the NRR mechanism of dual-metal catalysts, offering useful guidance for the rational design of catalysts with high selectivity and activity for NRR.

Nitrogen‐Doped Graphene Nanosheets for Sustainable Removal of Pharmaceutical Contaminants from Water: Kinetics and ANFIS Modeling

AbstractIn this work, nitrogen‐doped graphene nanosheets (NGS) were synthesized to remove diclofenac sodium (DFS) from water. The NGS exhibited 99.8 % removal efficiency, adsorption capacity of 278 mg g−1 for DFS within 30 min, and excellent reusability up to 5 cycles of adsorption. The experimental data fit well with pseudo‐second order kinetic model and Langmuir isotherm model. X‐ray photoelectron spectroscopy (XPS) and FTIR studies revealed that the carboxylic group, triazine group, graphitic‐N, and pyridinic‐N groups were involved in the adsorption of DFS. The adaptive neuro‐fuzzy inference system (ANFIS) was modeled for accurate prediction of optimizing parameters for the maximum adsorptive removal (%) of DFS by NGS. A subsequent cytotoxicity assay of NGS on a green alga Chlamydomonas sp. signified non‐toxic nature. This study suggests NGS to be a promising economic adsorbent for water remediation in resource‐poor environments to fulfill “UN‐Sustainable Development Goal‐ 6”.

Iron single Atom–Iron nanoparticles dual-deposited nitrogen-doped graphene hybrid as an innovative catalyst to enhance the oxygen reduction reaction

The fabrication of an effective electrocatalyst for cathodic oxygen reduction reaction (ORR) is important to enhance the performance of fuel cell applications. Here, we prepared a novel hybrid material based on the combination of iron single atoms–small iron nanoparticles homogeneously distributed on the surface of nitrogen-doped graphene nanosheets (FeSA-FeNPs/NG). The achieved FeSA–FeNPs/NG material exhibited high catalytic ORR behaviors with high positive values of +0.94 V and +0.81 V for onset potential and half-wave potential, respectively, as well as the remarkable stability with 90% retention of initial current over an operation period of 15 000 s), superior to commercial Pt/C in 0.1 M KOH medium. In addition, the material favored a four-electron reaction pathway along with good methanol crossover tolerance towards ORR. The outstanding catalytic performance could be attributed to the formation of a unique microporous nanoarchitecture owning large specific surface area of 103.63 m2 g−1 and high conductivity, which create rich active sites and fast charge transfer ability, thus effectively accelerating the adsorption and catalyzation processes to convert oxygen reactant to product during ORR. These findings suggest a novel route for the synthesis of potential catalysts exhibiting excellent efficiency and cost effectiveness for fuel cell industries.

Synthesis of nitrogen-doped graphene and its strengthening effect on aluminium metal matrix composite

The present study investigates the potential of nitrogen-doped graphene nanosheets (NDG) as a reinforcing material in aluminum (Al) metal matrix composites. The NDG was synthesized through a mechanochemical process involving solid-state dry ball milling of graphite with melamine. Characterization techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy were used to evaluate the properties of the NDG. For the first time, NDG was employed as a reinforcing material to improve the wettability, minimize the formation of aluminum carbide, and enhance the strength through strong interfacial bonding. The ultimate tensile and compressive yield strengths of Al/NDG composites were found to be 124% and 67% higher, respectively, with only 0.2 wt% NDG content. Furthermore, the tensile strength of the 0.2 wt% NDG/Al composite was found to be 72% higher than that of the 0.5 wt% graphene/Al composite. The fractured surface of the Al/NDG composite was investigated by XRD and FESEM techniques. XRD analysis revealed the presence of low-intensity peaks of aluminum nitride (AlN) and no evidence of aluminum carbide. The tribological properties of NDG were studied through wear rate and coefficient of friction (COF) measurements. The results showed a decrease in COF by 45% with an increase in NDG concentration from 0.1 to 0.5 wt%, and a decrease in wear rate by 25% and 71% for the same NDG concentration range. These results provide insight into the potential of NDG as an additive to improve tribological properties in aluminum-based composites. Further research is needed to understand the underlying mechanisms and optimize the performance thoroughly.

The New Materials for Battery Electrode Prototypes.

In this article, we present the performance of Copper (Cu)/Graphene Nano Sheets (GNS) and C-π (Graphite, GNS, and Nitrogen-doped Graphene Nano Sheets (N-GNS)) as a new battery electrode prototype. The objectives of this research are to develop a number of prototypes of the battery electrode, namely Cu/GNS//Electrolyte//C-π, and to evaluate their respective performances. The GNS, N-GNS, and primary battery electrode prototypes (Cu/GNS/Electrolyte/C-π) were synthesized by using a modified Hummers method; the N-doped sheet was obtained by doping nitrogen at room temperature and the impregnation or the composite techniques, respectively. Commercial primary battery electrodes were also used as a reference in this research. The Graphite, GNS, N-GNS, commercial primary batteries electrode, and battery electrode prototypes were analyzed using an XRD, SEM-EDX, and electrical multimeter, respectively. The research data show that the Cu particles are well deposited on the GNS and N-GNS (XRD and SEM-EDX data). The presence of the Cu metal and electrolytes (NH4Cl and MnO2) materials can increase the electrical conductivities (335.6 S cm-1) and power density versus the energy density (4640.47 W kg-1 and 2557.55 Wh kg-1) of the Cu/GNS//Electrolyte//N-GNS compared to the commercial battery (electrical conductivity (902.2 S cm-1) and power density versus the energy density (76 W kg-1 and 43.95 W kg-1). Based on all of the research data, it may be concluded that Cu/GNS//Electrolyte//N-GNS can be used as a new battery electrode prototype with better performances and electrical activities.

Anisotropic thermoelectric properties in hydrogenated nitrogen-doped porous graphene nanosheets.

By using density functional theory calculations combined with the nonequilibrium Green's function method and machine learning, we systematically studied the thermoelectric properties of four kinds of porous graphene nanosheets (PGNS) before and after nitrogen doping. The results show that the thermoelectric performance of porous graphene nanosheets along the armchair or zigzag chiral direction is improved due to the dramatically enhanced power factor caused by nitrogen doping. The calculated ZT values of nitrogen-doped porous graphene nanosheets are boosted by about one order of magnitude compared with those of undoped porous graphene nanosheets at room temperature. More importantly, an anisotropic thermoelectric transport is found in the nitrogen-doped porous graphene nanosheets. The results show that the ZT values of nitrogen-doped porous graphene nanosheets along the zigzag transport direction are nearly 11 times larger than those of them along the armchair transport direction. These results reveal that the thermoelectric properties of porous graphene nanosheets can be well regulated by nitrogen doping, and provide a good theoretical guidance for their application in thermoelectric devices.

Facile Preparations of Electrochemically Exfoliated N-Doped Graphene Nanosheets from Spent Zn-Carbon Primary Batteries Recycled for Supercapacitors Using Natural Sea Water Electrolytes

A single production of nitrogen-doped graphene nanosheets was developed in this present work from a spent Zn-C primary battery. The electrochemically exfoliated nitrogen-doped graphene nanosheets (EC-N-GNS) was applied in supercapacitor symmetric devices. As-prepared EC-N-GNS was utilized for a symmetric supercapacitor with natural seawater multivalent ion electrolyte. The recycling of graphite into nitrogen-doped graphene was characterized by X-ray diffraction and RAMAN spectroscopy. The few-layered morphological structures of EC-N-GNS were analyzed by field emission scanning electron microscope and field emission transmission electron microscope. The electrochemical analysis of the cyclic voltammetry curves observed an electrochemical double-layer capacitor (EDLC) behavior with a potential window of −0.8 V to +0.5 V. The electrochemical galvanostatic charge—discharge study was obtained to be maximum specific capacitance (Csp)—67.69 F/g and 43.07 F/g at a current density of 1 A/g. We promising the facile single-step electrochemically exfoliated EC-N-GNS was obtained from a waste zinc-carbon primary battery to recycle the graphite electrodes. The superior electrochemical performance comparatively bulk graphite and EC-N-GNS for potential energy storage supercapacitor applications.

Effect of nitrogen doping on the structure and electrochemical properties of vertical graphene sheets prepared by HWP-CVD

3D nitrogen-doped vertically-oriented graphene nanosheets (3D N/VGs) were controllably prepared by helicon wave plasma chemical vapor deposition (HWP-CVD) employing argon, methane, and nitrogen by varying the N2 flow rate (RN2) without any catalyst and substrate heating during the growth. The effect of plasma gas phase species on the growth structure of N/VGs thin films was studied. The influence of nitrogen doping content on the structure and properties of VGs was analyzed. A growth model for the preparation of N/VGs by HWP-CVD was proposed. The results show that the elevated doping content of nitrogen atoms promotes enhanced CH4 dissociation and access to more H atoms, leading to an elevated nanosheet number density and a reduced growth rate. More excited N atoms could be embedded into the C vacancy to replace the missing C atom and restore the hexagonal network and increasing the nitrogen content. N/VGs with lower defect densities obtained with enhanced doping of nitrogen. The effective average distance between defects increases with nitrogen content, and the tunneling phenomenon is apparent, increasing resistance. Electrochemical performance tests showed that VGs with high nitrogen atomic content have higher specific capacitance and rate performance, up to 1340 μF/cm2 and 91.7%, respectively.

Ultrasensitive Pressure Sensor Sponge Using Liquid Metal Modulated Nitrogen-Doped Graphene Nanosheets.

Wearable pressure sensors are crucial for real-time monitoring of human activities and biomimetic robot status. Here, the ultrasensitive pressure sensor sponge is prepared by a facile method, realizing ultrasensitive pressure sensing for wearable health monitoring. Since the liquid metal in the sponge-skeleton structure under pressure is conducive to adjust the contact area with nitrogen-doped graphene nanosheets and thus facilitates the charge transfer at the interface, such sensors exhibit a fast response and recovery speed with the response/recovery time 0.41/0.12 s and a comprehensive response range with a sensitivity of up to 476 KPa-1. Notably, the liquid metal-based spongy pressure sensor can accurately monitor the human body's pulse, the pressure on the skin, throat swallowing, and other activities in real time, demonstrating a broad application prospect. Those results provide a convenient and low-cost way to fabricate easily perceptible pressure sensors, expanded the application potential of liquid metal-based composites for future electronic skin development.

Hierarchical three dimensional polyaniline/N‐doped graphene nanocomposite hydrogel for energy storage applications

AbstractWith the rapid development of portable, lightweight, and flexible electronics, the requirement for advanced energy storage systems has arisen that need to be flexible and cost‐effective with higher power/energy densities. In this context, a two‐step approach has been adopted to develop a binder‐free and flexible supercapacitor electrode on carbon cloth based on hierarchical three dimensional (3D) conducting polymer hydrogels. Firstly, nitrogen‐doped graphene (NGN) was synthesized using urea as a reducing as well as a doping agent. Subsequently, polyaniline (PAni) hydrogel has been grown on NGN nanosheets via insitu oxidative polymerization in the vicinity of carbon cloth and further utilized as an electrode for electrochemical measurements. Here, phytic acid was used as a gelatinizer and as a dopant resulting in the formation of a cross‐linked hydrogel structure. The direct deposition of PAni/NGN nanocomposite on carbon cloth strengthens the juncture involving the carbon cloth and electrode material, resulting in enhanced electron transmission. The 3D hydrogel architecture ascertains robust contact between electrolyte and electrode for an efficient charge storage system. For a two‐electrode symmetric arrangement, at 1 A/g, PAni/NGN nanocomposite hydrogel displayed a maximum specific capacitance of 808.7 F/g due to the pseudocapacitive reaction on/near the accessible surface area, as well as an outstanding rate capability and cyclic performance due to electric double layer capacitance (EDLC). The supercapacitor cell delivered maximum specific power and specific energy value of 0.44 kW/kg and 13.63 Wh/kg, respectively. Thus, the composite hydrogel has the benefit of being able to be utilized directly as binder‐free supercapacitor electrodes, leading to viable choice for high‐performance and cost‐effective energy storage devices.

Vanadium carbide and nitrogen-doped graphene nanosheets based layered architecture for electrochemical evaluation of clioquinol detection and energy storage application

Herein, we report the oxidized-vanadium carbide (V8C7Tx) hybridized with nitrogen-doped graphene nanosheets (VC/NG NSs) nanocomposite using hydrothermal followed by sonochemical approach. The oxidized V8C7Tx is shown to be enriched with O-terminated functional groups, which also improves the electrochemical performance of the nanocomposite. Then for the first time, VC/NG NSs nanocomposite is reported as an efficient electrocatalyst for the detection of CQL. The cyclic voltammetry (CV) experiments were performed at the working potential from 0 to 0.7 V (vs. Ag/AgCl). Surprisingly, the nanocomposite's multilayer structure offers a large number of active sites with a high electron transfer rate for CQL detection. The fabricated drug sensor exhibits a lower oxidation potential (0.46 V) and a greater peak current response (12.05 µA) than previously reported sensors. Under optimum circumstances, the fabricated sensors analytically well performed by means of low detection limit (9 nM), wide linear range (0.5–585 µM), and appreciable recovery results (∼98%, (n = 3)) in human urine samples. Furthermore, the nanocomposite shows a high gravimetric capacitance of 235 F g−1 at 1 A g−1 in 1 M KOH, which is the highest value among alkali-based electrolytes for VC based electrodes. Moreover, the nanocomposite demonstrated robust cycling performance even after 8000 cycles with ∼95% capacitance retention. The presence of O-terminated functional groups, various oxidation states of vanadium (+2, +3, and +4), good conducting and catalytic characteristics of N-graphene are worked together to improve electrochemical performance in sensor and energy storage. Thus, the current study offers a promising MXene based nanocomposite material for high-performance electrochemical applications.