Effect Of Carbon Materials Research Articles

Effect of carbon material and surfactant on ink property and resulting surface cracks of fuel-cell microporous layers

Ensuring the consistency of electrode structure in proton exchange membrane fuel cells is highly desired yet challenging because of wide-existing and unguided cracks in the microporous layer (MPL). The first thing is to evaluate the homogeneity of MPL with cracks quantitatively. This paper proposes the homogeneity index of a full-scale MPL with an area of 50 cm2, which has yet to be reported in the literature to our knowledge. Besides, the effects of the carbon material and surfactant on the ink and resulting MPL structure have been studied. The ink with a high network development degree produces MPL with low crack density, but the ink with high PDI produces MPL with low crack homogeneity. The polarity of the surfactant and the non-polarity of PTFE are not mutually soluble, resulting in the heterogeneous PTFE distribution. The findings of this study provide guidelines for MPL fabrication.

Revealing the effect of conductive carbon materials on the sodium storage performance of sodium iron sulfate.

Na2Fe2(SO4)3 (NFS), as a promising cathode for sodium-ion batteries, is still plagued by its poor intrinsic conductivity. In general, hybridization with carbon materials is an effective strategy to improve the sodium storage performance of NFS. However, the role of carbon materials in the electrochemical performance of NFS cathode materials has not been thoroughly investigated. Herein, the effect of carbon materials was revealed by employing various conductive carbon materials as carbon sources. Among these, the NFS coated with Ketjen Black (NFS@KB) shows the largest specific surface area, which is beneficial for electrolyte penetration and rapid ionic/electronic migration, leading to improved electrochemical performance. Therefore, NFS@KB shows a long cycle life (74.6 mA h g-1 after 1000 cycles), superior rate performance (61.5 mA h g-1 at a 5.0 A g-1), and good temperature tolerance (-10 °C to 60 °C). Besides, the practicality of the NFS@KB cathode was further demonstrated by assembling a NFS@KB//hard carbon full cell. Therefore, this research indicates that a suitable carbon material for the NFS cathode can greatly activate the sodium storage performance.

Effect of Carbon Material on Hydrogen Storage in Mg/MgH2

Effect of Carbon Material on Hydrogen Storage in Mg/MgH2

Effects of activated carbon, biochar, and carbon nanotubes on the heterogeneous Fenton oxidation catalyzed by pyrite for ciprofloxacin degradation

Pyrite and engineering carbon materials have received increasing attention for their catalytic potential in Fenton reactions due to their extensive sources and low cost. However, effects of carbon materials on the degradation of pollutants by pyrite-catalyzed heterogeneous Fenton oxidation have not been fully understood. In this study, the performance of pyrite-catalyzed heterogeneous Fenton system on the degradation of ciprofloxacin (CIP) was investigated in the presence of activated carbon (AC), biochar (BC), and carbon nanotubes (CNTs). Synchronous and asynchronous experiments (adsorption and catalysis) were conducted to elucidate the roles of the carbon materials in pyrite-catalyzed Fenton reactions. The results demonstrated that all the three carbon materials accelerated the pyrite-catalyzed Fenton oxidation of CIP. Under the experimental conditions, the reaction rates, which were obtained by fitting the synchronous experimental results with the pseudo-first-order kinetic model, of pyrite/AC, pyrite/BC and pyrite/CNTs with H2O2 for the removal of CIP were 8.28, 3.40 and 3.37 times faster than that of pyrite alone. Adsorption experiments and characterization analysis showed that AC had a higher adsorption capacity than BC and CNTs for CIP, which enabled it to distinguish itself in assisting the pyrite-catalyzed Fenton oxidation. In the presence of the carbon materials, the adsorption effect should not be neglected when studying the catalytic performance of pyrite. Free radical quenching experiments and electron spin-resonance spectroscopy (ESR) were used to detect and identify free radical species in the reactions. The results showed that hydroxyl radicals (•OH) contributed significantly to the degradation of CIP. The addition of carbon materials promoted the production of •OH, which favored the degradation of CIP. The results of this study suggested that the synergistic effect of oxidation and adsorption promoted the removal of CIP in pyrite/carbon materials/H2O2 systems, and coupling pyrite and carbon materials shows great potential in treating antibiotic wastewater.

Study on the effect of carbon materials with different morphologies on the hydrogen generation performance of aluminum: A strategy to control the hydrogen generation rate of aluminum

Activated aluminum composites have received widespread attention because they can generate hydrogen by reacting with water at room temperature quickly and easily. Regulating the hydrogen generation rate of activated aluminum composites is urgent, and it is a challenging task for the application of activated aluminum composites in industrial hydrogen generation. Herein, three types of carbon materials with different morphologies are used to prepare three corresponding activated aluminum composites by ball milling. Their hydrogen generation rate and hydrogen generation volume are studied in detail. The results show that the activated aluminum composites prepared by adding graphene sheet materials with a two-dimensional planar structure have faster hydrogen generation rate than the activated aluminum composites prepared by adding cellulose with a one-dimensional linear structure and spherical carbon materials with a three-dimensional spherical structure. By observing the microscopic morphology of the activated aluminum composite and the collected quenched intermediate hydrolysis products, the regulation mechanism of different carbon materials on the water reaction rate of the activated aluminum composites is analyzed. In addition, the application of activated aluminum composite Al-7.5Bi-2.5GS in rapid gas generation is also simulated, and the results show that composite Al-7.5Bi-2.5GS has the potential to be used in rapid water rescue devices.

Effect of carbon materials as cathode on wastewater treatment and bioelectricity generation in a double chambered microbial fuel cell

Microbial fuel cell (MFC) is a promising and sustainable technology that has high efficiency to produce renewable energy and treat wastewater simultaneously. The effect of carbon materials on the removal of synthetic wastewater in the anodic chamber and electricity generation were investigated using a double chambered MFC. In this study, a double chambered reactor made up of anodic and cathodic chambers separated by proton exchange membrane has been developed. Carbon plate and carbon felt were characterized using scanning electron microscopy. Results revealed that 1.20 times higher chemical oxygen demand removal of synthetic wastewater using carbon felt (50.90%) as compared with that of carbon plate (43.52%). The maximum voltage output produced by carbon felt (280.20 mV) was 20.70% higher than carbon plate (222.20 mV) as cathode in MFC. The surface morphology of carbon materials has significant effect on the oxygen reduction reaction reactivity at cathodic chamber.

Crop Enhancement of Cucumber Plants under Heat Stress by Shungite Carbon.

Heat stress negatively impacts plant growth and yield. The effects of carbon materials on plants in response to abiotic stress and antioxidant activity are poorly understood. In this study, we propose a new method for improving heat tolerance in cucumber (Cucumis sativus L.) using a natural carbon material, shungite, which can be easily mixed into any soil. We analyzed the phenotype and physiological changes in cucumber plants maintained at 35 °C or 40 °C for 1 week. Our results show that shungite-treated cucumber plants had a healthier phenotype, exhibiting dark green leaves, compared to the plants in the control soil group. Furthermore, in the shungite-treated plants, the monodehydroascorbate content (a marker of oxidative damage) of the leaf was 34% lower than that in the control group. In addition, scavengers against reactive oxygen species, such as superoxide dismutase, catalase, and peroxidase were significantly upregulated. These results indicate that the successive pre-treatment of soil with a low-cost natural carbon material can improve the tolerance of cucumber plants to heat stress, as well as improve the corresponding antioxidant activity.

In English

By the density functional theory method with the exchange-correlation functional B3LYP, the basis set 6-31G(d,p) and Grimme dispersion corrections, the energy values has been calculated of intermolecular interaction between adjacent polyamide fragments, and the effect of graphene-like nanoclusters on the similar values for intermolecular complexes of polyamide fragments with graphene-like nanoclusters has been evaluated. The effect of carbon materials on the energy magnitudes of covalent bonds in the polymer matrix of polyamide has been also examined. Comparison of the energy values of intermolecular interaction between two monomers (‑86.0 kJ/mol, two hydrogen bonds) and two dimers (-302.0 kJ/mol, three hydrogen bonds) indicates that the energy of interaction between two components consists of that of hydrogen bonds and the energy contribution of dispersive forces. The energy of intermolecular interaction between two dimers with the graphene matrix (C 110 H 26 ) is approximately 40 kJ/mol higher (-346.2 kJ/mol) compared to respective value for two monomers. The less value of the interaction energy (-325.0 kJ/mol) for the nanocomposite with C 96 H 24 species is due to the insufficient size of the selected model for the graphene matrix. The analysis of the hydrogen bond lengths between the oxygen atom of carbonyl group and hydrogen one of amino group indicates that, regardless of length of linkage of the polymeric chain of polyamide (monomer and dimer) and the size of the graphene-like matrix (C 96 H 24 and C 110 H 26 ) in the nanocomposite, the hydrogen bond in composites is shorter in comparison with a those values in complexes without a carbon matrix. This indicates a greater strength of the bond, that is, the presence of a carbon matrix increases the strength of the formed nanocomposite, that explains the increase in the melting point compared with that of the original polymer. In the nanocomposite formed polyamide - a carbon matrix for all the models studied, the energy of intermolecular interaction in the nanocomposite increases significantly compared to respective value between two fragments of pure polyamide, so indicating an increase in the thermal stability of this nanocomposite what is confirmed by experimental data.

Effects of carbon materials on fire protection and smoke suppression of waterborne intumescent coating

The new carbon materials bring significant progress in fire resistance coating and technology, especially carbon nano materials. Aiming to improve the fire resistance, expanded graphite (EG), carbon nanotubes (CNTs), fullerene (C60), graphene (Gr) were applied as filler in the waterborne intumescent coatings to investigate fire resistance, thermal stability, smoke suppression and water resistance. The effects of carbon materials on fire protection and smoke suppression of waterborne intumescent coating were investigated in detail by fire retardant test, thermogravimetry (TG), differential scanning calorimeter (DSC), smoke density test and water resistance test. The carbon layers were characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and particle size distribution. The results of fire protection test and SEM indicated that the fire resistance of coatings was enhanced by adding 1% content of carbon materials. TGA analysis showed that carbon materials could increase the residual weight and thermal stability of the coatings. After immersed in water for 360 h, the results of water resistance test, the carbon materials could form barrier to improve the water resistance of the coatings. Especially, the graphene exhibited the best performance among all the carbon materials.

Effect of carbon materials and bismuth particle size on hydrogen generation using aluminum-based composites

A series of activated aluminum/carbon/bismuth composites were prepared and characterized using scanning electron microscope (SEM) and X-ray diffraction (XRD). Then, the performance of these activated aluminum composites with respect to hydrogen generation was explored. The experimental results show that the hydrogen yield and generation rate of the aluminum composite are improved by adding carbon and bismuth to aluminum. In particular, the Al-7.5%nanoBi-2.5%GNS composite milled for 4 h demonstrated the best hydrogen generation in terms of yield and rate. The maximum hydrogen generation rate of Al-7.5%nanoBi-2.5%GNS composite could reach 23.3 mL s−1 g−1 at 30 °C. Besides, the relationship between initial reaction temperature, milling time, and hydrogen generation of these composites was studied. Moreover, the hydrolysis products of these aluminum composites were investigated.

Enhancement of Drought Tolerance in Cucumber Plants by Natural Carbon Materials.

Stress induced by climate change is a widespread and global phenomenon. Unexpected drought stress has a substantial effect on the growth and productivity of valuable crops. The effects of carbon materials on living organisms in response to abiotic stresses remain poorly understood. In this study, we proposed a new method for enhancing drought tolerance in cucumber (Cucumis sativus L.) using carbon nanotubes and natural carbon materials called shungite, which can be easily mixed into any soil. We analyzed the phenotype and physiological changes in cucumber plants grown under conditions of drought stress. Shungite-treated cucumber plants were healthier, with dark green leaves, than control plants when watering was withheld for 21 days. Furthermore, compared with the control cucumber group, in the shungite-treated plants, the monodehydroascorbate content of the leaf, which is a representative marker of oxidative damage, was 66% lower. In addition, major scavenger units of reactive oxygen species and related drought stress marker genes were significantly upregulated. These results indicate that successive pretreatment of soil with low-cost natural carbon material improved the tolerance of cucumber plants to drought stress.

Graphene oxide-ordered mesoporous silica composite supported Co-based catalysts for CO hydrogenation to higher alcohols

Higher alcohols synthesis (HAS) directly from syngas has attracted lots of attentions due to its advantages on environmental-friendliness, versatility and economy. Recently, researches proposed that the Co-Co2C dual sites could act as efficient active species for HAS. But the role of carbides as well as its formation process needs further investigation. Here, we synthesized a series of graphene oxide (GO)-ordered mesoporous silica (OMS) composite supported cobalt-based catalysts, which presented excellent activity and selectivity in HAS. It is found that the addition of GO could not only improve the dispersion of cobalt species, but also act as an electron donor to promote CO adsorption and disassociation on Co species, both leading to a higher catalytic activity. The electron donor effect of GO could facilitate the carbide formation process as well. The increased ratio of Co2C/Co with GO addition linearly improved the alcohol selectivity in HAS. However, excess GO addition would cover a part of active sites and weaken the electron donor effect, resulting in a lower alcohol yield. This work gives insights into the effects of carbon materials on active sites distribution and performance of cobalt-based catalysts, which could be used to rationalize the design of catalysts for HAS.

Effects of carbon materials on the formation of disinfection byproducts during chlorination: Pore structure and functional groups

Release of carbon materials (CMs) into water and wastewater treatment systems occurs due to their increasing utilization as adsorbents for water treatment. When the CMs, mixed with natural organic matter (NOM), interact with disinfectants used during water treatment (e.g. chlorine), the released CMs can affect the formation of disinfection byproducts (DBPs). In this study, three common CMs were investigated to reveal their possible effects and the mechanisms of DBP formation during the chlorination of NOM. The experimental results indicate that DBPs generation decreased by 10–40% in the presence of CMs when Suwannee River humic acid (SRHA) was chlorinated. The adsorption of SRHA by CMs was hypothesized as the major cause for the DBPs inhibition. CMs could irreversibly adsorb DBP precursors in their mesopores through π-π bonding and hydrophobic effects. OH groups on the surface of CMs were shown to be critical for DBPs inhibition through linking with the OH or COOH groups on the surface of NOM via hydrogen bonding. The study also showed that water chemistry parameters, such as pH and salinity, can affect DBP formation by changing the adsorption of NOM onto CMs. With diverse NOM components, the presence of CMs resulted in decreased formation of trichloromethane from 57.1 μg/L to 23.8, 38.4, and 40.4 μg/L when coal-made activated carbon (CAC), wheat straw-made BC pyrolyzed at 300 °C (WSBC300), and multiwalled carbon nanotubes (MWCNTs), respectively, were added to surface water; and from 30.6 μg/L to 20.0, 19.2, and 13.2 μg/L when CAC, WSBC300, and MWCNTs, respectively, were added to wastewater.

Effect of Carbon Materials on the Slag Foaming in EAF Process

Effect of Carbon Materials on the Slag Foaming in EAF Process

Carbon Material with High Specific Surface Area Improves Complex Copper Ores’ Bioleaching Efficiency by Mixed Moderate Thermophiles

The catalysis of carbon materials with different specific surface areas (SSA) (2, 400, 800 and 1200 m2/g) on complex copper ores bioleaching by moderately mixed thermophiles was investigated. The copper extractions increased with the rise in SSA of carbon materials. A recovery of 98.8% copper in the presence of 1200 m2/g activated carbon was achieved, and improved by 30.7% and 76.4% compared with biotic control and chemical leaching. Moreover, the addition of 1200 m2/g activated carbon adsorbed large amount of bacteria, accelerated the oxidation rate of ferrous iron and maintained the solution redox potential at relatively low values, and significantly increased the dissolution of primary copper sulfide (62.7%) compared to biotic control (6.0%). Microbial community succession revealed that activated carbon changed the microbial community composition dramatically. The S. thermosulfidooxidans ST strain gained a competitive advantage and dominated the microbial community through the whole bioleaching process. The promoting effect of carbon material with higher SSA on copper extraction was mainly attributed to better galvanic interaction, biofilm formation, direct contact and lower redox potential.

The effects of carbon materials with different dimensionalities on the flow instabilities of LLDPE (linear low density polyethylene)

Melt flow instability of LLDPE (Linear Low Density Polyethylene) and its composites with three kinds of carbon fillers with different dimensionalities, including multi-wall carbon nanotubes (MWCNTs), thermally reduced graphene (TRG) and carbon black (CB), was evaluated. A periodic oscillation in entrance pressure drop during the process of wall slip was observed. It was demonstrated that the dimensionalities of the fillers played a significant role in the rheological behaviors for LLDPE composites. The critical shear rate for the onset of the stick-slip transition increased when MWCNTs added but decreased with the addition of TRG. However, in terms of the LLDPE/CB composites, there was no obvious changes for this critical shear rate. Mechanisms for the effects of these fillers on the flow instabilities were proposed according to the molecular structure and the movement of polymer chains.

Direct Synthesis of Pure H2O2 Aqueous Solution by CoTPP/Ketjen-Black Electrocatalyst and the Fuel Cell Reactor

Hydrogen peroxide as an important and green oxidant for chemical process is manufactured by the anthraquinone (AQ) process, which is an indirect synthesis method and consumes a large quantity of energy. We have reported the direct and efficient synthesis of pure H2O2 aqueous solutions by O2 and H2 fuel-cell reactions using the Co-N-C compound cathode. Catalysis of Co-N-C-compound was improved in this work. Precursors of Co-N-C compounds were prepared by impregnation of 5,10,15,20-tetrakis(phenyl)-21H, 23H-porphyrin cobalt (II) (CoTPP) on various carbon materials. Effects of carbon materials, heat-treatment temperatures, Co loadings of the precursors on the electrocatalysis for H2O2 synthesis were studied from a current density (j), a H2O2 formation rate (R(H2O2)), a H2O2 concentration (C(H2O2)) and a faradic efficiency for H2O2 formation (FE(H2O2)). The most active and effective Co-N-C electrocatalyst is Ketjen-Black supported CoTPP (0.05 Co-wt%) activated at 1023 K in He stream as denoted 0.05 wt%/CoTPP/KB(1023 K) and shows a highest C(H2O2) and FE(H2O2) of 5.5 mol dm−3 (18.7 wt%) and 55%, respectively, with a high Co turnover-frequency of 26 s−1. Effects of amounts of the 0.05 wt%/CoTPP/KB(1023 K) electrocatalyst coated on the VGCF-base cathode were studied on the H2O2 synthesis and distributions of open-circuit voltages as electromotive forces to cathode and anode over-potentials and an IR-drop (VGCF: vapor-growing carbon fiber).

Unexpected co-immobilization of lactoferrin and methylene blue from milk solution on a Nafion/MWCNT modified electrode and application to hydrogen peroxide and lactoferrin biosensing

Lactoferrin (LAF), an iron-binding glycoprotein has several health benefits ranging from anti-cancer, anti-inflammatory and antimicrobial activities against large number of microorganisms and is present abundantly in milk. Enzyme linked immunosorption assay based analytical protocol has been often referred for the selective detection of LAF in real samples. Herein, we report a simple electrochemical methodology for the direct recognition of LAF in raw milk using a methylene blue (MB) immobilized iron impurity (2.1wt.%) containing multiwalled carbon nanotube/nafion modified glassy carbon electrode system. It is interesting to observe that upon potential cycling of GCE/Nf-MWCNT in MB dissolved milk system, both MB and LAF got co-immobilized on the electrode surface, designated as GCE/Nf-MWCNT@MB-LAF and showed a selective bio-electrocatalytic reduction signal for H2O2 at −0.4V vs Ag/AgCl in milk or pH 7 PBS system. From control electrochemical experiments such as loading MB in pH 7 phosphate buffer solution and simulated milk sample and effect of carbon material (activated charcoal, graphite nanopowder and functionalized MWCNT) on preparation of the LAF modified electrode, it is revealed that iron impurity in the MWCNT, MB and LAF of the modified electrode involved in the electron-shuttling process to facilitate the H2O2 reduction reaction. By utilizing this novel process, selective bio-electrocatalytic sensing of H2O2 with current sensitivity and detection limit values 0.035μA μM−1 and 3.2μM respectively and specific recognition of LAF in raw and water diluted milksamples have been successfully demonstrated.

The effect of carbon material on the electroanalytical determination of 4-chloro-3-methylphenol using the sol-gel derived carbon ceramic electrodes

A surface renewable ceramic electrode modified in its entire volume with multi-walled carbon nanotubes (CNT-CCE) was obtained by the sol-gel method. Bare carbon ceramic electrode (GP-CCE) was also produced for comparison. The surface morphology and electrochemical properties of the electrodes were analyzed. The morphology and topography were tested by means of, respectively, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Cyclic voltammetry was used to analyze the electrochemical features (e.g. potential window). Moreover, the obtained electrodes were used for square wave voltammetric (SWV) determination of 4-chloro-3-methylphenol (PCMC). The calibration curves were obtained for GP-CCE and CNT-CCE in the chosen optimal experimental conditions (composition of the supporting electrolyte, step potential, amplitude, frequency). The concentration ranges of 9–29μmolL−1 and 3–32μmolL−1 were recorded, respectively, for GP-CCE and CNT-CCE. The proposed method was validated, and the limit of detection (LOD) and the limit of quantitation (LOQ) were calculated. Finally, the obtained electrodes and the developed procedure were successfully applied to determine PCMC in spiked tap water. Satisfactory results were obtained, and they demonstrated that using MWCNTs instead of GP improves the quality of the CCE electrodes.

Effect of carbon material on Pd catalyst for formic acid electrooxidation reaction

Effect of several usually used carbon materials on Pd catalyst for formic acid electrooxidation reaction is studied by physical characterization and electrochemical measurements. New active sites are formed due to the Pd and carbon interaction which is confirmed by the XPS measurements, and electrochemical impedance spectroscopy confirms that the presence of the carbon material reduced the charge transfer resistance. Further, an improved fuel cell performance is observed when integrating the carbon-modified Pd catalyst in to a direct formic acid fuel cell. The results reveal that the carbon material is not only used as support, but also involves the new active sites formation.