Reduced Graphene Oxide Carbon Nanotubes Research Articles

Miniaturized Electrochemical Gas Sensor with a Functional Nanocomposite and Thin Ionic Liquid Interface for Highly Sensitive and Rapid Detection of Hydrogen.

Hydrogen has been widely used in industrial and commercial applications as a carbon-free, efficient energy source. Due to the high flammability and explosion risk of hydrogen-air mixtures, it is vital to develop sensors featuring fast-responding and high sensitivity for hydrogen leakage detection. This paper presents a miniaturized electrochemical gas sensor by elaborately establishing a nanocomposite and thin ionic liquid interface for highly sensitive and rapid electrochemical detection of hydrogen, in which a remarkable response time and recovery time of approximately 6 s was achieved at room temperature. A screen-printed carbon electrode was modified with a reduced graphene oxide-carbon nanotube (rGO-CNT) hybrid and platinum-palladium (Pt-Pd) bimetallic nanoparticles to realize high sensitivity. To achieve miniaturization and high stability of the sensor, a thin-film room-temperature ionic liquid (RTIL) was employed as the electrolyte with a significantly decreased response time. The fast-responding hydrogen sensor demonstrates excellent performance with high sensitivity, linearity, and repeatability at concentrations below the lower explosive limit of 4 vol %. The engineered high-performance interface and gas sensor provide a promising and effective strategy for gas sensor design and rapid hazardous gas monitoring.

Influence of Reduced Graphene Oxide and Carbon Nanotubes on the Structural, Electrical, and Photoluminescent Properties of Chitosan Films.

Chitosan is a biopolymer with unique properties that have attracted considerable attention in various scientific fields in recent decades. Although chitosan is known for its poor electrical and mechanical properties, there is interest in producing chitosan-based materials reinforced with carbon-based materials to impart exceptional properties such as high electrical conductivity and high Young's modulus. This study describes the synergistic effect of carbon-based materials, such as reduced graphene oxide and carbon nanotubes, in improving the electrical, optical, and mechanical properties of chitosan-based films. Our findings demonstrate that the incorporation of reduced graphene oxide influences the crystallinity of chitosan, which considerably impacts the mechanical properties of the films. However, the incorporation of a reduced graphene oxide-carbon nanotube complex not only significantly improves the mechanical properties but also significantly improves the optical and electrical properties, as was demonstrated from the photoluminescence studies and resistivity measurements employing the four-probe technique. This is a promising prospect for the synthesis of new materials, such as biopolymer films, with potential applications in optical, electrical, and biomedical bioengineering applications.

Aminated reduced graphene oxide-carbon nanotube composite gas sensors for ammonia recognition

Composites based on carbon nanomaterials exhibit many advantageous properties for gas sensing, such as high and fast response, room-temperature operation, and tailoring sensitivity by energy level engineering. However, only the first attempts to employ such chemosensors for gas-sensing applications have been made. In this work, an on-chip multisensor array of carboxylated carbon nanotubes (CNT), aminated reduced graphene oxide (rGO-Am), and CNT/rGO-Am nanocomposite was fabricated using a simple and low-cost spray deposition method. The CNT/rGO-Am sensor demonstrated a fast and high response to NH3 in dry air at low (25 ppm) and high (400 ppm) concentrations of 70 and 115 %, respectively. The response to NH3 in humid air increased and reached 160 % at 400 ppm. The chemosensor exhibited high sensitivity and selectivity toward ammonia with a low detection limit estimated to be below 0.2 ppb. Linear discriminant analysis of the sensor responses to different concentrations of NH3, dry and humid air revealed better discrimination when CNT/rGO-Am composites were used in combination with CNT and rGO-Am sensors in an array. This study demonstrates that composite sensors with junctions between carbon nanomaterials have great potential for practical applications in fast and selective gas detection at room temperature and different humidity.

Analysis of CNT and rGO Mediation for an Efficient Super-Capacitive Response in Cr-Doped Co3O4 Based Composites

The synthesis of novel and high capacitance electrode materials has attracted much attention over the last few decades to meet the needs of electrode materials in supercapacitors. Cobalt oxide, one of several vanadium oxides, has recently gained popularity due to its unique layered structure, phase transition, and applications in supercapacitors. Here, we present structural, morphological, and electrochemical analysis of Cr-doped Co3O4 nanostructures and their carbon nanotubes/reduced graphene oxide (CNT/rGO) based composites. Hydrothermal and solvothermal routes are followed to prepare the samples. The active material is developed via a polymer-based binder and is used as the electrode in a three-electrode electrochemical system. X-ray diffraction confirms the spinel-type cubic crystal structure, while the stoichiometric elemental contents are verified via an energy dispersive X-ray spectroscopy. Well-shaped layered growth of the nanocomposites is revealed by field emission scanning electron microscopy. The electrochemical analysis is performed using a 2 M KOH electrolyte solution and a three-electrode electrochemical setup. The pure and Cr-doped nanocomposite samples reveal a pseudo capacitive behavior in all samples. The systematic capacitive and resistive response of the samples has also been presented in this report. The aforementioned attributes make the synthesized specimen a potential candidate for an electrode material.

Enhanced electrochemical nitrate reduction to ammonia with nanostructured Mo2C on carbon nanotube-reduced graphene oxide hybrid support.

The electrochemical nitrate reduction reaction (NO3-RR) is emerging as a promising method for ammonia production under ambient conditions while simultaneously addressing nitrate pollution. Due to the complexity of NO3-RR, which involves multi-electron/proton transfer and competes with the hydrogen evolution reaction (HER), the development of efficient electrocatalysts with high activity and stability is crucial. In this study, we report the use of Mo2C nanoparticles homogeneously dispersed on a carbon nanotube-reduced graphene oxide hybrid support (Mo2C/CNT-RGO) as an effective electrocatalyst for NO3-RR. The three-dimensional CNT-RGO hybrid provides a large surface area for electrolyte contact, enhanced electrical conductivity, and prevents the aggregation of Mo2C nanoparticles. Consequently, the Mo2C/CNT-RGO electrocatalyst demonstrated high NO3-RR performance, achieving a maximum NH3 production rate of 5.23 mg h-1 cm-2 with a faradaic efficiency of 95.9%. Mo2C/CNT-RGO also exhibited excellent long-term stability during consecutive cycling tests. This work presents a promising strategy for developing high-performance and durable NO3-RR electrocatalysts.

Long-term stability of lithium–sulfur batteries via synergistic integration of nitrogen-doped graphitic carbon-coated cobalt selenide nanocrystals within porous three-dimensional graphene-carbon nanotube microspheres

Three-dimensional porous microspheres consist of highly conductive reduced graphene oxide-carbon nanotube (rGO‒CNT) framework with well-embedded cobalt selenide (CoSe2) nanocrystals coated with N-doped graphitic carbon (NGC) were synthesized (referred as “P–CoSe2@NGC/rGO‒CNT” microspheres) and utilized as an electrocatalytic interlayer to enhance the performance of lithium-sulfur (Li–S) batteries. The incorporation of the NGC layer and rGO‒CNT framework not only enhances the electronic conductivity significantly but also offers numerous conductive pathways (primary and secondary) for efficient electron transport. Macropores (φ = 100 nm) formed by the decomposition of PS nanobeads (φ = 200 nm) guarantee effective electrolyte penetration and short diffusion pathways. Moreover, the CoSe2 nanocrystals offer a multitude of polar active sites that effectively anchor polysulfide intermediates, reducing the loss of active material. Benefiting from the nanostructure merits, Li–S cells featuring a P–CoSe2@NGC/rGO‒CNT-coated separator and a conventional sulfur electrode demonstrated outstanding rate capability (up to 2.0 C) and remarkable cycling stability (1000 cycles at 2.0 C). Even under more demanding cell conditions, such as high sulfur content (71 %), high sulfur loading (4.6 mg cm−2), and low E/S (5.6 μL mg−1) ratio, the cell exhibits impressive cycling stability with 420 cycles at 0.1 C, along with feasible rate performance up to 0.3 C.

Boosting redox kinetics using rationally engineered cathodic interlayers comprising porous rGO–CNT framework microspheres with NiSe2-core@N-doped graphitic carbon shell nanocrystals for stable Li–S batteries

Here, we propose the synthesis of a three-dimensional (3D) nanostructure comprising NiSe2-core@N–doped graphitic carbon (NGC) shell nanocrystals securely implanted within a highly conductive and porous reduced graphene oxide–carbon nanotube (rGO–CNT) framework (3D P-NiSe2@NGC/rGO–CNT), using spray pyrolysis technique followed by selenization and utilized as multifunctional cathodic interlayers in lithium–sulfur (Li–S) cells. The uniformly distributed arrays of macropores (ϕ = 100 nm) were formed by thermal decomposition of polystyrene nanobeads (ϕ = 200 nm). The porous structure shortens the charge diffusion length, allowing rapid charge transport and efficient electrolyte percolation besides accommodating unwanted volume perturbations. The NGC shell surrounding the NiSe2 nanocrystals acted as the primary conduction conduit for electron transport, while the self-supporting rGO–CNT framework served as a secondary pathway for consecutive electron transfer besides enhancing the structural robustness. Further, the polar NiSe2 nanocrystals offered numerous chemisorption sites for effectively capturing polysulfides, thus minimizing the shuttling effect and increasing active material utilization. The Li–S cell exhibited improved rate performance (till 4.0C) and excellent cycling stability (1000 cycles at 2.0C, average capacity decay rate of 0.04% per cycle). Even at severe cell parameters (effective S content = 74%, S loading = 4.5 mg cm−2, and electrolyte/sulfur = 5.7 µL mg−1), the cells delivered a stable rate performance and long-term cycling (400 cycles at 0.1C, average decay rate of 0.10% per cycle). We believe the nanostructure design strategy that we developed for this study could spur the development of more enduring and practical Li–S battery technology.

An Electrochemical Screen-Printed Sensor Based on Gold-Nanoparticle-Decorated Reduced Graphene Oxide-Carbon Nanotubes Composites for the Determination of 17-β Estradiol.

In this study, a screen-printed electrode (SPE) modified with gold-nanoparticle-decorated reduced graphene oxide-carbon nanotubes (rGO-AuNPs/CNT/SPE) was used for the determination of estradiol (E2). The AuNPs were produced through an eco-friendly method utilising plant extract, eliminating the need for severe chemicals, and remove the requirements of sophisticated fabrication methods and tedious procedures. In addition, rGO-AuNP serves as a dispersant for the CNT to improve the dispersion stability of CNTs. The composite material, rGO-AuNPs/CNT, underwent characterisation through scanning electron microscopy (SEM), ultraviolet-visible absorption spectroscopy (UV-vis), Fourier-transform infrared (FTIR) spectroscopy, and atomic force microscopy (AFM). The electrochemical performance of the modified SPE for estradiol oxidation was characterised using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The rGO-AuNPs/CNT/SPE exhibited a notable improvement compared to bare/SPE and GO-CNT/SPE, as evidenced by the relative peak currents. Additionally, we employed a baseline correction algorithm to accurately adjust the sensor response while eliminating extraneous background components that are typically present in voltammetric experiments. The optimised estradiol sensor offers linear sensitivity from 0.05-1.00 µM, with a detection limit of 3 nM based on three times the standard deviation (3δ). Notably, this sensing approach yields stable, repeatable, and reproducible outcomes. Assessment of drinking water samples indicated an average recovery rate of 97.5% for samples enriched with E2 at concentrations as low as 0.5 µM%, accompanied by only a modest coefficient of variation (%CV) value of 2.7%.

Simultaneous Electrochemical Analysis of Uric Acid and Xanthine in Human Saliva and Serum Samples Using a 3D Reduced Graphene Oxide Nanocomposite-Modified Electrode

Accurate and effective diagnosis and individualized management of gout can be potentially achieved by detecting uric acid (UA) and xanthine (XT) simultaneously using an easy-to-use method. Herein, we report simultaneous detection of UA and XT using a 3-dimensional (3D) macroporous gold nanoparticle-incorporated reduced graphene oxide–carbon nanotube nanocomposite (GNP/rGO-CNT). The GNP/rGO-CNT was simply prepared on a glassy carbon electrode (GCE) by one-step electrochemical deposition/co-reduction. It displayed highly sensitive and selective responses to UA and XT, showing excellent stability and good reproducibility in neutral pH. It was demonstrated that 3D GNP/rGO-CNT on GCE could detect UA and XT in human saliva and blood serum simultaneously. This GNP/rGO-CNT for simultaneous detection of UA and XT in human body fluids can be utilized for monitoring drug adherence for gout treatment, together with gout diagnosis.

S/N-codoped carbon nanotubes and reduced graphene oxide aerogel based supercapacitors working in a wide temperature range

Among many supercapacitor electrode materials, carbon materials are widely used due to their large specific surface area, good electrical conductivity and high economic efficiency. However, carbon-based supercapacitors face the challenges of low energy density and limited operating environment. This work reports a facile self-assembled method to prepare three-dimensional carbon nanotubes/reduced graphene oxide (CNTs/rGO) aerogel material, which was applied as both positive and negative electrodes in a symmetric superacapacitor. The fabricated supercapacitor exhibited prominent capacitive performance not only at room temperature, but also at extreme temperatures (−20 ∼ 80 °C). The specific capacitances of the symmetric supercapacitors based on CNTs/rGO at a weight ratio of 2:5 respectively reached 107.8 and 128.2 F g−1 at 25 °C and 80 °C with KOH as the electrolyte, and 80.0 and 144.6 F g−1 at −20 °C and 60 °C with deep eutectic solvent as the electrolyte. Notably, the capacitance retention and coulombic efficiency of the assembled supercapacitors remained almost unchanged after 20,000 cycles of charge/discharge test over a wide temperature range. The work uncovered a possibility for the development of high-performance supercapacitors flexibly operated at extreme temperatures.

Sensitive electrochemical detection of enrofloxacin in eggs based on carboxylated multi-walled carbon nanotubes-reduced graphene oxide nanocomposites: Molecularly imprinted recognition versus direct electrocatalytic oxidation

A sensitive electrochemical method for detecting enrofloxacin was proposed using carboxylated multi-walled carbon nanotubes-reduced graphene oxide (MWCNT-COOH-RGO) nanocomposites. The MWCNT-COOH-RGO nanocomposites were firstly electrodeposited on a bare electrode, followed by electropolymerization of molecularly imprinted polymers. Enrofloxacin was determined by the mechanisms of direct electrocatalytic oxidation and molecularly imprinted recognition, respectively. Under the optimized conditions, a response range of 5.0×10–7 M to 5.5×10–5 M and limit of detection (LOD) of 2.3×10–7 M were obtained by direct electrocatalytic oxidation of enrofloxacin using chronoamperometry. By contrast, the response range of 1.0×10–10 M to 5.0×10–5 M and LOD of 2.5×10–11 M were achieved by molecularly imprinted recognition of enrofloxacin using square-wave voltammetry. Moreover, the proposed method exhibited good repeatability, stability and selectivity, and could be used for enrofloxacin detection in egg samples with satisfactory results.

Preparation of reduced graphene oxide-carbon nanotubes membranes for conductive heating membrane distillation treatment of humic acid

Membrane distillation (MD) has attracted extensive attention as a technology to solve water scarcity in the fields of desalination. Surface-heated membrane distillation techniques that have emerged in recent years have improved flux due to the elimination of temperature polarization, but still suffer from membrane fouling. The use of electrochemical techniques for in-situ cleaning of membrane fouling in MD is expected to be an effective solution. Herein, electroactive membranes were prepared by loading mixtures of reduced graphene oxide (rGO) and carbon nanotube (CNT) with four mass ratios on polytetrafluoroethylene (PTFE) hydrophobic membranes. A series of analytical methods, such as scanning electron microscopy, atomic force microscopy, pore size analysis, water contact angle, Raman spectroscopy, membrane surface zeta potential, and cyclic voltammetry curve, were employed to characterize the properties of the rGO-CNT membranes. The best separation performance and conductivity were achieved at a 2:1 mass ratio of rGO to CNTs (R2 membrane). Then, the rGO-CNT membranes were applied to a conductive heating vacuum membrane distillation system to treat humic acid (HA). Compared with the PTFE membrane, the four rGO-CNT membranes showed a significant improvement in the rejection of HA. Using the rGO-CNT membranes as the cathode and the titanium as the anode, after a certain potential was applied, the flux decreases slowly. The fluxes of all rGO-CNT membranes were maintained over 9.5 kg/(m2·h) for 10 h of continuous operation. An increase in potential helps to increase change by alleviating membrane fouling. The highest flux and HA rejection reached 13 kg/(m2·h) and 99.8 %, respectively, with R2 membrane and −5 V potential applied. The mechanism of antifouling included electrostatic repulsion and electrocatalytic oxidation.

Well-dispersive Pt nanocrystals anchored onto 3D boron and nitrogen double-doped reduced graphene oxide–carbon nanotube frameworks as efficient electrocatalysts for methanol oxidation

A bottom-up self-assembly method is developed to the fabrication of well-dispersive Pt nanocrystals anchored onto 3D B and N double-doped reduced graphene oxide-CNT frameworks, which express superior electrocatalytic performance for methanol oxidation. • 3D B and N double-doped graphene-CNT frameworks are fabricated via a co-assembly strategy; • The homogeneous distribution of Pt nanocrystals on the hybrid frameworks is realized; • The interconnected porous network and optimized electronic structure provide numerous active sites; • The as-derived catalysts express exceptional electrochemical performance toward methanol oxidation. The development of direct methanol fuel cell (DMFC) technology is an effective way to solve the problems of environmental pollution and energy shortage, while the scarcity of the highly-efficient anode catalysts with low cost severely limits its commercial use. In this work, we report a robust and convenient approach for the bottom-up construction of well-dispersive Pt nanocrystals anchored onto three-dimensional (3D) porous boron and nitrogen double-doped reduced graphene oxide–carbon nanotube frameworks (Pt/BNRGO-CNT) via a controllable co-assembly process. This architectural design can achieve a series of useful structural merits, such as 3D cross-linked porous network, large presence of B and N atoms, homogeneous Pt dispersibility, and high electrical conductivity. Consequently, the resulting Pt/BNRGO-CNT electrocatalysts exhibit excellent catalytic activity, strong anti-toxicity ability, and good long-term stability for methanol oxidation reaction, far exceeding those of Pt catalysts supported by the conventional undoped reduced graphene oxide, carbon nanotube, and carbon black matrixes.

Preparation and reinforcement performance of RGO-CNTs-SiO2 three-phase filler for rubber composites

Rubber reinforcement technology is developing towards the direction of high efficiency and multi-functionality, and the reinforcement of rubber by a single-component filler can no longer meet the requirements. Nanocomposite fillers have become the development trend of high-performance reinforcing fillers due to the complementary advantages and synergistic reinforcing effects of each component. Reduced graphene oxide-carbon nanotubes (RGO-CNTs) composites were prepared by a method of electrostatic assembly. The non-covalent modified RGO-CNTs was used as a substance to grow in situ SiO2 nanoparticles (RGO-CNTs-SiO2), and the RGO-CNTs-SiO2 three-phase fillers were obtained. The RGO-CNTs-SiO2 three-phase fillers were further used to study the reinforcing properties of hydrogenated nitrile rubber (HNBR). Furthermore, the effects of RGO-CNTs-SiO2 with different component contents on the reinforcing properties of HNBR were systematically studied. The TEM images of RGO-CNTs-SiO2 show that the RGO and CNTs promotes mutual dispersion, and the SiO2 nanoparticles (average diameter 7 nm) are highly dispersed on the surface of RGO-CNTs. The characterization of RGO-CNTs-SiO2/HNBR indicates that the RGO-CNTs-SiO2 efficiently weaken the filler network and improve the filler-rubber interaction. The results show that the three-phase fillers produce obvious synergistic reinforcing effects. The highest tensile strength (30.1 MPa) of RGO-CNTs-SiO2/HNBR is achieved at the RGO:CNTs mass ratio of 1:5, the RGO-CNTs mass percentage of 2%, and the filler loading of 50 phr. This work demonstrates the considerable promise for developing three-phase filler-based rubber composites.

Carbon-supported nano tungsten bronze aerogels with synergistically enhanced photothermal conversion performance: Fabrication and application in solar evaporation

Solar interfacial evaporation is an effective and sustainable strategy to solve the shortage of fresh water. Nowadays, fully converting the near-infrared light with significant thermal effect, and reducing the energy loss in evaporation stage are the key factors to achieve higher evaporation rate. Herein, the nano cesium tungsten bronze (Cs0.32WO3) with exceptional near-infrared absorption property was loaded on reduced graphene oxide-carbon nanotubes (rGO-CNTs) composite aerogel, drastically enhancing the evaporation efficiency from 61.0% to 85.9%, which can be explained by the remarkable synergistic effect between rGO-CNTs and nano Cs0.32WO3 in improving the photothermal conversion performance. As a result, the solar evaporators assembled by the fabricated rGO-CNTs-Cs0.32WO3 aerogels and corn straw grooves achieved an evaporation rate of 1.93 kg m−2 h−1, exceeding the previously-investigated carbon aerogels/foams, natural plants and tungsten-based compound systems. The characterization results reveal that the loading of nano Cs0.32WO3 contributes to the partial restoration of π-conjugated structure in rGC, increasing solar absorption and the corresponding thermal energy released by the lattice vibration. Meanwhile, the oxygen vacancies and carrier density of Cs0.32WO3 nanoparticles increase after compositing with rGC, which further enhances the local surface plasma resonances (LSPR) effect. Significantly, the hydrophilic functional groups and excellent wettability of composite aerogel and corn straw play crucial effect in accelerating water transport, activating water molecules and reducing evaporation energy consumption. In a word, the unique construction of rGO-CNTs-Cs0.32WO3 aerogels presents a novel approach for the design of solar-driven freshwater production system, the application expansion of nano tungsten bronze and carbon aerogels.

Resistance matching materials nanoarchitectonics for better performances in water evaporation-driven generators

The improvement of electricity production for water evaporation-driven generators (WEGs) remains a challenge. Herein, two types of WEGs were designed to study the resistance matching for improving the electricity production using the method of nanoarchitectonics. One type of reduced graphene oxide/carbon nanotube (RGO/CNT) WEG was constructed using RGO with adjustable resistances as working material and CNTs with fixed resistance as electrode material. The other type of graphene oxide (GO)/RGO WEG was constructed using RGO with adjustable resistance as electrode material and GO with fixed resistance was used as working material. The open circuit voltage of RGO/CNT increased from 15 to 56 mV and then decreased to 22 mV with increasing RGO resistance. The short circuit current of RGO/CNT also first increased and then decreased. The performance of GO/RGO was similar with that of RGO/CNT. Typically, the RGO/CNT and GO/RGO WEG showed the highest performance when the working material to electrode material resistance ratio was 2272 and 2365, respectively. It showed that the best resistance ratio of working material to electrode material was in the range of 2000–2500, which helped to improve about 2–5 times of electricity efficiency in the WEG. The present work provides a new direction for optimizing performance of WEGs.

Preparation and properties of reduced graphene oxide-carbon nanotubes aerogel/cotton flexible composite fabric with electromagnetic shielding function

The electromagnetic pollution has become a serious problem with the rapid development of electromagnetic industry. The present work prepared an electromagnetic interference (EMI) functional composite fabric. Reduced graphene oxide (rGO)-carbon nanotubes (CNTs) aerogel with three-dimensional (3-D) architecture were coated to the cotton fabric with the assistance of waterborne polyurethane (WPU). The structure of graphene aerogel was affected by the amount of CNTs. Small amount of CNTs is helpful to minish the pore size of aerogel and thus improve the EMI value. However, it has been shown that excess CNTs will destroy the 3-D architecture of graphene aerogel. Result shows that the EMI shielding effectiveness exceeded 35 dB when the weight ratio of rGO and CNTs was 7:3, and EMI value of the corresponding composite fabric samples reached 34 dB. Consequently, excellent EMI results were obtained by the unique 3-D rGO-CNTs aerogel in the case of a small nano-carbon material amount. The present work will be expected to make contributions to the practical application of rGO-CNTs aerogel.

Vertical silica nanochannels supported by nanocarbon composite for simultaneous detection of serotonin and melatonin in biological fluids

Herein we report the simultaneous determination of serotonin (5-HT) and melatonin (MT) by using highly ordered and vertically-oriented mesoporous silica-nanochannel films (VMSF) on highly electrochemically reduced graphene oxide-carbon nanotubes (HErGO-CNT) composite substrate. Such VMSF/HErGO-CNT with compact 2D–2D layered structure is fabricated on indium tin oxide (ITO) electrodes via a two-step electrochemical process, namely the electrodeposition of ErGO-CNT film onto the ITO surface by cyclic voltammetry and subsequently growth of VMSF on the ErGO-CNT/ITO surface by electrochemically assisted self-assembly method, during which graphene oxide (GO) is subjected to the two-time electrochemical reduction to form HErGO. The CNT encased in the GO sheets served as electronic conducting wires, which not only can promote the electrochemical reduction of GO but also contribute to a certain degree of hydrophobicity, facilitating the controllable electrodeposition of ErGO-CNT composites on ITO under its safe use potential window. In addition, doping CNT is able to enlarge the layer gap between graphene sheets and thus improves the electroactive area and mass transfer of the nanocarbon composite substrate. Furthermore, the underlying HErGO-CNT acts as an efficient electroactive layer and the outer VMSF possesses electrostatic preconcentration and anti-fouling functions, synergistically realizing the direct electrochemical analysis of 5-HT and MT in two complex biological fluids (human whole blood and artificial cerebrospinal fluid).

Enhanced Oxygen Evolution Reaction with a Ternary Hybrid of Patronite-Carbon Nanotube-Reduced Graphene Oxide: A Synergy between Experiments and Theory.

This work reports the hybridization of patronite (VS4) sheets with reduced graphene oxide and functionalized carbon nanotubes (RGO/FCNT/VS4) through a hydrothermal method. The synergistic effect divulged by the individual components, i.e., RGO, FCNT, and VS4, significantly improves the efficiency of the ternary (RGO/FCNT/VS4) hybrid toward the oxygen evolution reaction (OER). The ternary composite exhibits an impressive electrocatalytic OER performance in 1 M KOH and requires only 230 mV overpotential to reach the state-of-the-art current density (10 mA cm-2). Additionally, the hybrid shows an appreciable Tafel slope with a higher Faradaic efficiency (97.55 ± 2.3%) at an overpotential of 230 mV. Further, these experimental findings are corroborated by the state-of-the-art density functional theory by presenting adsorption configurations, the density of states, and the overpotential of these hybrid structures. Interestingly, the theoretical overpotential follows the qualitative trend RGO/FCNT/VS4 < FCNT/VS4 < RGO/VS4, supporting the experimental findings.

Rational design of multi-walled carbon nanotube-reduced graphene oxide hierarchical porous paper toward superior electromagnetic interference shielding

The ever-intensifying electromagnetic (EM) pollution drives the intense demand for EM shielding materials. Through evaporative self-assembly and hydrazine hydrate vapor reduction strategy, intricate multiwalled carbon nanotube (MWCNT) ingeniously anchors on the porous reduced graphene oxide (RGO) paper. The synthesized MWCNT-RGO composite paper manifests a better EMI shielding performance compared with pure RGO. Typically, S5-15 (5 wt% MWCNT, 15 g mixture) furnishes the maximum electromagnetic shielding effectiveness up to 47.88 dB with a thickness of 1.04 mm in the X band. These ingenious bicomponent microstructures possess abundant heterointerfaces and defects. Consequently, they synergistically balance the impedance matching, and contribute to conduction loss, polarization relaxation and multiple reflection and scattering. This work supplies the inspiration for the facile preparation of carbon composite with high EM shielding efficiency and thin lamellation by consolidating MWCNT and RGO to form porous heterostructure.