Graphene Oxide Carbon Nanotubes Research Articles

Microwave-assisted hydrothermal synthesis of three-dimensional NbOPO4-reduced graphene oxide-carbon nanotube composite for high performance sodium-ion battery anode

Sodium-ion batteries (SIBs) have aroused more and more academic and industrial interest due to their decent electrochemical performance and the cost-effectiveness of sodium (Na) resource. However, fabricating an appropriate anode material with high specific capacity, long-term cycle stability and superior rate capability remains a great challenge. Here, we adopt an efficient microwave-assisted hydrothermal method to prepare layered niobium oxyphosphate (NbOPO4) nanosheets, which grows on the single-walled carbon nanotubes (SWCNT) and reduced graphene oxide (rGO) (NbOPO4-rGO-SWCNT). Benefiting from three-dimensional hierarchical architecture combining NbOPO4 nanosheets with rGO-SWCNT framework with excellent electrical conductivity, NbOPO4-rGO-SWCNT electrode delivers a higher reversible specific capacity (323.2 mAh g−1 at 0.1 A g−1) and superior rate capability (147.9 mAh g−1 at 5 A g−1) than that of NbOPO4 (143.1/43.5 mAh g−1). Ex-situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements further reveal the electrochemical mechanism that reversible reaction between niobium phosphate (NbPO4) and niobium (Nb) occurs after the initial intercalation-conversion reaction, which contributes to the stable reversibility and high-rate capability in the following cycling. This work not only indicates that NbOPO4-rGO-SWCNT can act as a desirable anode material for SIBs, but also provide new insights to material design for niobium oxyphosphate composite.

Application of nanoporous core–shell structured multi-walled carbon nanotube–graphene oxide nanoribbons in electrochemical biosensors

Here, we demonstrated the synthesis of nanoporous core–shell structured multi-walled carbon nanotube–graphene oxide nanoribbons (NP-MWCNT@GONRs) and their electrochemical applications to biosensors. The NP-MWCNT@GONRs were prepared by a hydrothermal method with ZnCl2 as the activation agent followed by an acid treatment. The NP-MWCNT@GONRs exhibited a hierarchical micro/mesoporous structure and a high surface area (2.4 times higher than that of MWCNTs). NP-MWCNT@GONR-modified glassy carbon electrodes (GCEs) were used to electrochemically detect biomolecules, including ascorbic acid (AA), dopamine (DA), and uric acid (UA). This NP-MWCNT@GONR-modified GCE exhibited high sensitivity of approximately 15 μA μM−1 cm−2 and low limits of detection of 0.12 μM in DA, demonstrating that it is a promising electrode for biosensors.

An electrochemical sensor based on reduced graphene oxide/β-cyclodextrin/multiwall carbon nanotubes/ polyoxometalate tetracomponent hybrid: Simultaneous determination of ascorbic acid, dopamine and uric acid

In this work, a novel tetracomponent hybrid electrochemical sensor was constructed with reduced graphene oxide/β-cyclodextrin/multiwall carbon nanotubes/ polyoxometalate (RGO-CD-MWCNT-POM), which achieved simultaneous detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA). First, the RGO-CD-MWCNT-POM was synthesized by assembly of graphene oxide (GO), β-cyclodextrin (CD), and multiwall carbon nanotube (MWCNT), with subsequent reduction of GO in the assistance of polyoxometalate (POM). Afterward, the morphology and structural properties were characterized by transmission electron microscope (TEM), energy dispersive X-ray mapping (EDS), scanning electron microscope (SEM), Raman spectroscopy, and thermogravimetric analysis (TGA). After its modification on glassy carbon electrode (GCE), RGO-CD-MWCNT-POM could simultaneously detect AA, DA, and UA by voltammetry method. Its enhanced electrochemical sensing performances derive from the combined merits of each component: supramolecular recognition from CD, excellent electronic properties from carbon components, and electrocatalyst from POM. Under optimal conditions, the linear ranges of AA, DA and UA were 5–2000, 0.5–300 and 1–400 μM with the detection limits with 0.84 μM, 0.04 μM, 0.05 μM, respectively. The proposed sensor was also well applied in practical simultaneous measurement in urine sample with the recovery ranges of 94%∼108%. Our work suggests the fabricated sensor is promising for constructing excellent sensing platform.

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.

Gas sensing performance of biomass carbon materials promoted by nitrogen doping and p-n junction

In order to realize the resource utilization of waste orange peel, N-doped porous carbon derived from orange peel (NCOP) was prepared by simple carbonization and first used in the field of gas sensors. Compared with the reduced graphene oxide (RGO) and multi walled carbon nanotubes (MWCNTs), the responses of NCOP to five analytes were improved by 3.32 ∼ 66.72 times and the effect of N doping on the gas sensitivity of NCOP was analyzed by First-principles calculations. Furthermore, the NCOP/RGO composite with p-n junctions was prepared to improve the gas sensing properties. The theoretical limit of detection of NCOP and NCOP/RGO composites to formaldehyde vapor was determined to be 16.7 and 7.7 ppb, respectively. The response time and recovery time of NCOP and NCOP/RGO to all five analytes were no more than 15.9, 5.4 s and 14.4, 5.0 s, respectively. More importantly, the sensor array based on RGO, MWCNTs, NCOP and NCOP/RGO can discriminatively and quickly detect multiple analytes at room temperature. The study showed that both self-doping and heterojunction can effectively improve the gas sensitivity of biomass carbon materials, which provided a useful reference for the resource utilization of biomass waste and the development of gas sensors.

Broad-Spectrum Antimicrobial ZnMintPc Encapsulated in Magnetic-Nanocomposites with Graphene Oxide/MWCNTs Based on Bimodal Action of Photodynamic and Photothermal Effects.

Microbial diseases have been declared one of the main threats to humanity, which is why, in recent years, great interest has been generated in the development of nanocomposites with antimicrobial capacity. The present work studied two magnetic nanocomposites based on graphene oxide (GO) and multiwall carbon nanotubes (MWCNTs). The synthesis of these magnetic nanocomposites consisted of three phases: first, the synthesis of iron magnetic nanoparticles (MNPs), second, the adsorption of the photosensitizer menthol-Zinc phthalocyanine (ZnMintPc) into MWCNTs and GO, and the third phase, encapsulation in poly (N-vinylcaprolactam-co-poly(ethylene glycol diacrylate)) poly (VCL-co-PEGDA) polymer VCL/PEGDA a biocompatible hydrogel, to obtain the magnetic nanocomposites VCL/PEGDA-MNPs-MWCNTs-ZnMintPc and VCL/PEGDA-MNPs-GO-ZnMintPc. In vitro studies were carried out using Escherichia coli and Staphylococcus aureus bacteria and the Candida albicans yeast based on the Photodynamic/Photothermal (PTT/PDT) effect. This research describes the nanocomposites’ optical, morphological, magnetic, and photophysical characteristics and their application as antimicrobial agents. The antimicrobial effect of magnetics nanocomposites was evaluated based on the PDT/PTT effect. For this purpose, doses of 65 mW·cm−2 with 630 nm light were used. The VCL/PEGDA-MNPs-GO-ZnMintPc nanocomposite eliminated E. coli and S. aureus colonies, while the VCL/PEGDA-MNPs-MWCNTs-ZnMintPc nanocomposite was able to kill the three types of microorganisms. Consequently, the latter is considered a broad-spectrum antimicrobial agent in PDT and PTT.

Enhanced naproxen adsorption by a novel β-cyclodextrin immobilized the three-dimensional macrostructure of reduced graphene oxide and multiwall carbon nanotubes

In this study, a novel β-cyclodextrin immobilized the three-dimensional macrostructure of reduced graphene oxide and multiwall carbon nanotubes (β-CD/rGO-MWCNTs) was synthesized with hydrothermal reduction and chemical crosslinking, adopting as an effective adsorbent for naproxen removal in aquatic environments. With a larger specific surface area (SSA) and excellent porous structure, β-CD/rGO-MWCNTs ensured a large internal space, which was conducive to the preservation of adsorption sites and naproxen diffusion. The maximum naproxen adsorption capacity (qm) value of β-CD/rGO-MWCNTs stood at 132.09 mg g−1 at room temperature, higher than that of most of the commonly used naproxen adsorbents. Such immense adsorption was attributed to hydrophobic interaction, electrostatic interaction, π/n-π interaction and hydrogen bonding. The naproxen adsorption kinetics and isotherm on the adsorbents match the pseudo-second-order kinetics model and the Freundlich model better. The thermodynamic parameters certified the naproxen adsorption on β-CD/rGO-MWCNTs as a favorable, thermodynamically feasible and exothermic process. The stable three-dimensional (3D) structure endowed the adsorbent with an excellent regeneration performance and practical application potential.

Sulfonated Poly(arylene ether nitrile)-Based Composite Membranes Enhanced with Ca2+ Bridged Carbon Nanotube-Graphene Oxide Networks

As the core component of proton exchange membrane fuel cells, proton exchange membranes (PEM) have attracted much attention of researchers. To trade-off the proton conductivity, dimensional stability and anti-oxidation ability of PEM, graphene oxide (GO) and acidized multi-walled carbon nanotubes (MWCNT) using calcium ion as coordination bridge (GO-Ca2+-MWCNT) was synthesized, and then incorporated into sulfonated poly(arylene ether nitrile) (SPEN) to fabricate SPEN/GO-Ca2+-MWCNT organic–inorganic composite membranes by solution-casting method and explore the influence of varying loading on performances as PEM. It was found that the proton conductivity of the composite membranes was higher than that of SPEN, while maintaining better dimensional stability, excellent anti-oxidation ability and good mechanical properties. All of these were attributed to the formation of three-dimensional structure between GO and MWCNT bridged by Ca2+ and the interaction between the sulfonic acid group and calcium ions in SPEN/GO-Ca2+-MWCNT composites. Particularly, the SPEN/GO-Ca2+-MWCNT-1 composite membrane exhibited excellent tensile strength of 71.45 MPa, better thermal stability as well as high proton conductivity (0.054 S/cm at 30 °C, and 0.193 S/cm at 90 °C), above 10–2 S/cm, satisfying the requirement of PEM. All in all, the results indicate that the filler with three-dimensional network structure can effectively improve the performances of SPEN, and the prepared composite membranes show potential applications in many fields.

Development of emphatic catalysts for waste water remediation via synchronized free radical and non-free radical routes with composites of strontium hexaferrite, graphene and multi-walled carbon nanotubes

Magnetic nanoparticles have shown exceptional potential in catalysis, however, their tendency to agglomerate has confined their use. The present work encompasses synthesis of eco-friendly and magnetic retrievable catalysts with different fractions of reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNT) as support for strontium hexaferrite (SrFe12O19) for the oxidative degradation of organic pollutants. The morphological, structural and magnetic properties of composites were estimated via PXRD, FT-IR, VSM, FE-SEM, HR-TEM, XPS and BET. The crystallite size decreased from 41.46 nm for SrFe12O19 to 35.85 nm and 33 nm for composites with 20% rGO and MWCNTs, respectively while the surface area increased substantially from 88.1 m2/g for SrFe12O19 to 118.4 and 131.3 m2/g. Further, the composites were employed as catalysts for the oxidative degradation of selected antibiotics and colourant via stimulation of two different oxidants, potassium peroxymonosulphate (PMS) and hydrogen peroxide (H2O2). The degradation followed pseudo first order kinetics with rate constant values increasing with rGO and MWCNT content. The increase in catalyst effectiveness can be ascribed to the synergistic interactions between rGO or MWCNT and SrFe12O19, which provided larger specific surface areas for adsorption and augmented number of catalytically active sites. Systematic chemical quenching studies unveiled a combined role of radical and non-radical species in oxidative degradation of pollutants. Moreover, the synthesized composites exhibited excellent recyclability upto four cycles forming the basis for their utilization as industrial catalysts.

Crystallization Behavior and Electrical Properties of Nanoparticle-Reinforced Poly(lactic Acid)-Based Films.

Graphene oxide (GO) and multiwalled carbon nanotubes with silver particles (MWNT-Ag) of different concentrations were used as nanofillers to prepare poly(lactic acid) (PLA) nanoparticle films through the solvent casting method. In this study, the effects of nanoparticles on the crystallization behavior, relationships between the dispersion and electrical properties, and hydrolytic degradation behaviors were investigated for the PLA/MWNT-Ag and PLA/rGO films. Differential scanning calorimetry was used to evaluate the crystallization behaviors of the PLA/MWNT-Ag and PLA/reduced GO (rGO) films. Electron probe microanalysis was performed to characterize the dispersion of MWNT-Ag, and X-ray diffraction and Raman spectroscopy were used to determine the degree of dispersion of rGO in the PLA matrix. The results showed that nanoparticles enhanced the crystallization kinetics of PLA as well as the hydrolytic degradation rate. From the measurement of electrical properties, the electrical conductivity of PLA/MWNT-Ag 1.0 wt% was much higher than that of the pure PLA and PLA/rGO films, showing that MANT and Ag nanoparticles contribute greatly to enhancing the electrical conductivity of the PLA/MWNT-Ag films.

Graphene Oxide-Carbon Nanotube (Go-Cnt) Hybrid Mixed Matrix Membrane for Pervaporative Dehydration of Ethanol

Graphene Oxide-Carbon Nanotube (Go-Cnt) Hybrid Mixed Matrix Membrane for Pervaporative Dehydration of Ethanol

Enhanced Naproxen Adsorption by a Novel Β-Cyclodextrin Immobilized the Three-Dimensional Macrostructure of Reduced Graphene Oxide and Multiwall Carbon Nanotubes

Enhanced Naproxen Adsorption by a Novel Β-Cyclodextrin Immobilized the Three-Dimensional Macrostructure of Reduced Graphene Oxide and Multiwall Carbon Nanotubes

Study the Effects of Carbon Nanotubes and Graphene Oxide Combinations on the Mechanical Properties and Flame Retardance of Epoxy Nanocomposites

Carbon-based fillers have attracted a lot of interest in polymer composites because of their ability to alter beneficial properties at low filler concentrations, good surface bonding with polymers, availability in different forms, etc. Carbon-based materials (such as fullerene, CNTs, graphene, and graphite) have been studied as fillers with enhanced fire resistance to epoxy resins. In order to reduce the flammability and improve the thermal stability of epoxy resin-based nanocomposite materials, which can be achieved by a simultaneous combination of graphene oxide and multiwall carbon nanotubes, the graphite oxide (GO) epoxy nanomaterial was developed by 1% wt.% GO combined with 0.02 wand 0.04 wt.% MWCNT. The homogeneous dispersion of GO and MWCNTs in epoxy resins is supported by ultrasonic vibrations. The results showed that when nanocomposite materials were present at the same time MWCNTs and GO, their mechanical properties and fire resistance were significantly improved. Nanomaterials are characterized by FT-IR spectroscopy and SEM imaging, mechanical strength, and flame retardant properties (LOI, UL94).

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.

A water permeability model of nano-reinforced cement pastes based on general effective media theory and multifractals

A theoretical model to predict the water permeability of nano-reinforced cement pastes from the pore structure (including the pore size distribution, pore interconnection, porosity and microcracks) is presented. The model is based on the general effective media (GEM) theory and multifractals, considering both the bridging of microcracks and capillary pores and the filling of nano gel pores of cement pastes reinforced with nano-admixtures. To validate the model, water permeability experiments were conducted using a cementitious composite reinforced with graphene oxide and multi-walled carbon nanotubes. The calculated results showed good agreement with the experimental measurements, with a decrease in the maximum error from 67.8% to 9.7% compared with the previously proposed GEM theory. Moreover, the theoretical calculations suggest that the reinforcing roles of nano-admixtures in cement paste to improve permeability-related properties may be mainly due to bridging effects in microcracks and capillary pores, rather than the filling of nano gel pores. The findings of this study enrich understanding of the mechanism of reinforcing cement-based materials with nano-admixtures. In addition, the permeability of cementitious composites can be measured directly, rather than the use if other using time-consuming methods.

Comparative Electrocatalytic Oxygen Evolution Reaction Studies of Spinel NiFe2O4 and Its Nanocarbon Hybrids

Electrocatalytic oxygen evolution reaction (OER) is one of the crucial reactions for converting renewable electricity into chemical fuel in the form of hydrogen. To date, there is still a challenge in designing ideal cost-effective OER catalysts with excellent activity and robust durability. The hybridization of transition metal oxides and carbonaceous materials is one of the most effective and promising strategies to develop high-performance electrocatalysts. Herein, this work synthesized hybrids of NiFe2O4 spinel materials with two-dimensional (2D) graphene oxide and one-dimensional (1D) carbon nanotubes using a facile solvothermal approach. Electrocatalytic activities of NiFe2O4 with 2D graphene oxide toward OER were realized to be superior even to the 1D carbon nanotube-based electrocatalyst in terms of overpotential to reach a current density of 10 mA/cm2 as well as Tafel slopes. The NiFe2O4 with 2D graphene oxide hybrid exhibits good stability with an overpotential of 327 mV at a current density of 10 mA/cm2 and a Tafel slope of 103 mV/dec. The high performance of NiFe2O4 with 2D graphene oxide is mainly attributed to its unique morphology, more exposed active sites, and a porous structure with a high surface area. Thus, an approach of hybridizing a metal oxide with a carbonaceous material offers an attractive platform for developing an efficient electrocatalyst for water electrochemistry applications.

Effect of the ratio of graphene oxide(GO) and multi-walled carbon nanotubes(MWCNTs) on metal friction and wear during mixing

Internal mixer is an important mixing component in industrial applications. Studies show that when a mixer operates for a long time, wear may appear at the end face of the internal mixer. On the other hand, abrasion of the end face increases the gap between the mixing chamber and the end face. Then, leakage occurs, which reduces the mixing effect and affects the rubber performance. Therefore, it is of significant importance to study the wear of the end face during the mixing process. Graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) have excellent electrical characteristics and thermal conductivity so that they have been widely used in various fields such as synthesized composite rubbers. GO and MWCNTs are mechanically blended into natural rubber to obtain GO/MWCNTs composite material. In the present study, the influence of the GO/MWCNTs ratio on the friction and wear of the end face of the internal mixer is analyzed. The obtained results show that MWCNTs and GO molecules interact to form a three-dimensional network structure, which has a greater impact on the degree of silica dispersion, silanization reaction, and metal wear. As the GO content increases, the average friction coefficient between rubber and metal, metal roughness, the proportion of abrasive wear, and the amount of metal wear gradually decrease. The lowest values can be achieved when the amount of added GO is set to 3 phr. When the GO in the mixture exceeds 3 phr, the friction coefficient between rubber and metal, and the metal roughness change, thereby affecting the proportion of abrasive wear and increasing the amount of metal wear in the mixing process. In this experiment, the amount of CNT that reduces GO aggregation is 6 phr. On the whole, when the ratio of GO/MWCNTs is 3/6, the synergistic effect of MWCNTs and GO molecules is maximized, the area of the three-dimensional network structure of GO/MWCNTs is the largest, the dispersibility of SiO2 is the best, and the amount of wear of the composite material on the metal is the lowest.

Synthesis and characterization of Pt/graphene-CNTs electrocatalyst for direct methanol fuel cell

In the present work we report a facile method for the synthesis of Pt nanoparticles supported reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) nanocomposite by an in-situ chemical reduction. The incorporation of MWCNTs to rGO leads to decrease in agglomeration between rGO sheets due to π – π interactions and higher loading of Pt nanoparticles. In this process, a mixture of exfoliated graphene oxide, CNTs and chloroplatinic acid was treated with a mixture of hydrazine hydrate and ammonium hydroxide at 95° C in an oil bath for 1 h. Pt nanoparticles of 4-6 nm size were homogeneously dispersed on rGO-CNTs nanocomposite as revealed by TEM analysis. Cyclic voltammetry measurements depict an anodic current density of 11.74 mA/cm2 that could be obtained using Pt/rGO-CNTs catalyst and 6.2 mA/cm2 using Pt/rGO catalyst during methanol oxidation, indicating that the catalytic activity of Pt/rGO-CNTs catalyst is almost 2 times higher than that of Pt/rGO catalyst. The electrochemical stability of Pt/rGO-CNTs catalyst was also found to be much higher as compared with that of Pt/rGO catalyst. Thus, Pt/rGO-CNTs catalyst has the potential to be used in the preparation of a promising anode material for direct methanol fuel cell. Copyright © 2016 VBRI Press

Construction of orderly self-growing nanosheet arrays on nickel foam by introducing novel carbon composite materials for high-performance supercapacitors

In this work, multiwalled carbon nanotube–graphene oxide nanoribbon@graphitic carbon nitride/NiCo layered double hydroxide/nickel foam (MWCNTs-GONRs@g-C3N4/NiCo-LDH/NF), named as MW-CN-LDH, is synthesized by a single-step microwave-assisted method using MWCNTs-GONRs@g-C3N4 as a novel carbon composite material. This synthesis strategy produces an electrode by self-growing nanosheet arrays on a nickel foam. It avoids the use of adhesives and reduces electrode impedance. Consequently, the MW-CN-LDH electrode exhibits high specific capacitance (2532.80 F∙g−1 at 1 A∙g−1) and exceptional performance (75.81% capacitance retention at 20 A∙g−1). Moreover, density functional theory (DFT) calculations reveal the material’s excellent conductivity and strong affinity to OH−, providing theoretical support to the experiment. The analysis results are consistent with test data. When used as an asymmetric supercapacitor, MW-CN-LDH//AC (active carbon) delivers high capacitance (193.36 F∙g−1) and long cycle life (91.92% capacitance retention after 10 000 cycles). Moreover, the maximum energy density (i.e., 77.61 Wh∙kg−1 at 0.85 kW∙kg−1 power density) is attained. This synthetic approach is a promising strategy for rapidly synthesizing high-performance supercapacitors, thus facilitating the extensive application of supercapacitors in the future.

A study on the effects of the addition of graphene oxide and multi-walled carbon nanotubes for surface modification on polyvinylidene fluoride membranes

We report graphene oxide (GO) and multi-walled carbon nanotube (MWCNT)-based polyvinylidene fluoride (PVDF) to improve the nanopore properties of pure PVDF for water treatment. The surface properties such as morphology, size of pores, and hydrophilicity were characterized using an optical microscope, FE-SEM, Raman spectra, and a capillary flow porometer. The membrane performance was evaluated for free residual chlorine and water flux. GO and MWCNTs were uniformly synthesized in the PVDF, and the hydrophobic properties of pure PVDF became hydrophilic because of the oxygen functional group of GO and the hydrophilic functional group of MWCNTs. The membrane with GO dramatically increased the number of pores from 145 to 1,197, with greater pore depth than that of pure PVDF. Additionally, the free residual chlorine removal performance of the GO and MWCNTs added PVDF was about 270 % and 415% improved compared to the pure PVDF and commercially used ultra-filter, respectively. These results reveal that the number and size of pores on the PVDF can be controlled and performance of the water treatment can be increased by the addition of carbon nanomaterials.