Nickel Carbon Research Articles

Flexible PVDF/carbon materials/Ni composite films maintaining strong electromagnetic wave shielding under cyclic microwave irradiation

In current work, multiwalled carbon nanotubes (MWCNTs), graphene nanoplatelets (GnPs) and nickel (Ni chains or flowers) were evenly dispersed in poly(vinylidene fluoride) (PVDF) matrices to fabricate composite flexible films.

P-doped 3D graphene network supporting uniformly vertical MoS2 nanosheets for enhanced hydrogen evolution reaction

In order to optimize the conductivity of molybdenum disulfide (MoS2) and promote its large-scale application as a catalyst for hydrogen evolution, MoS2 is usually used to form composites with conductive materials, but these hybrid materials suffer from scare active sites, overlapping and complicate process. In this work, phosphoric acid is used as a builder of stereoscopic structures, which can not only twist graphene sheets into a P-doped three-dimensional (3D) graphene network but also promote surface electron transport between graphene sheets. Without adding additional framework materials such as carbon nanotubes or nickel foam, stereoscopic MoS2/graphene structures are formed with a large number of twisted graphene sheets to support the vertical growth of MoS2 and expose the edge sites of MoS2, showing a low Tafel slope about 35 mV dec−1, a high current density of 900 mA cm−2 at about 300 mV and a robust stability over 2000 cycles. Thus, this work shows a possibility to synthesize an efficient catalyst on a large-scale for hydrogen evolution reaction, which can promote the realization of hydrogen economy.

Catalytic Dry Reforming and Cracking of Ethylene for Carbon Nanofilaments and Hydrogen Production Using a Catalyst Derived from a Mining Residue

In this study, iron-rich mining residue (UGSO) was used as a support to prepare a new Ni-based catalyst via a solid-state reaction protocol. Ni-UGSO with different Ni weight percentages wt.% (5, 10, and 13) were tested for C2H4 dry reforming (DR) and catalytic cracking (CC) after activation with H2. The reactions were conducted in a differential fixed-bed reactor at 550–750 °C and standard atmospheric pressure, using 0.5 g of catalyst. Pure gases were fed at a molar ratio of C2H4/CO2 = 3 for the DR reaction and C2H4/Ar = 3 for the CC reaction. The flow rate is defined by a GHSV = 4800 mLSTP/h.gcat. The catalyst performance is evaluated by calculating the C2H4 conversion as well as carbon and H2 yields. All fresh, activated, and spent catalysts, as well as deposited carbon, were characterized by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), temperature programmed reduction (TPR), and thermogravimetric analysis (TGA). The results so far show that the highest carbon and H2 yields are obtained with Ni-UGSO 13% at 750 °C for the CC reaction and at 650 °C for the DR reaction. The deposited carbon was found to be filamentous and of various sizes (i.e., diameters and lengths). The analyses of the results show that iron is responsible for the growth of carbon nanofilaments (CNF) and nickel is responsible for the split of C–C bonds. In terms of conversion and yield efficiencies, the performance of the catalytic formulations tested is proven at least equivalent to other Ni-based catalyst performances described by the literature.

RF Signal Multiplexer Embedded Into Multifunctional Composite Structure

This article describes the design and fabrication of an active four-port microwave switching network embedded into a multilayer aerospace composite structure. The multifunctional design is based on three broadband Integrated Device Technology (IDT) F2972 single-pole-double-throw (SP2T) RF switches and also includes a control and power supply circuit. The composite structure has been developed using a preimpregnated structural glass (S-Glass) material (Hexcel HexPly 914E). The conductive tracks of the switch and its ground plane have been fabricated using a nonwoven carbon–nickel–copper (CNC) veil material and a semiflexible conducting silver ink. This article contains an analysis of the electrical properties of both materials at microwave frequencies. The equivalent electrical conductivities of materials were determined using a curve fitting method that was then used to verify the computational modeling of the switching network. The RF switching network was developed based on a hybrid manufacturing approach. The RF transmission lines and a component of the control circuitry were transferred onto uncured pre-preg material using a laser to ablate select regions of the CNC veil material. Postcuring, flexible silver ink was additively printed onto the surface to create the remaining control circuits. The RF performance of the design has been evaluated, and it indicates that the overall performance was consistent with the measured S-parameters of the same circuit fabricated on Rogers 5880 substrate.

The application of an analytical model to solve an inverse heat conduction problem: Transient solidification of a Sn-Sb peritectic solder alloy on distinct substrates

Three distinct alloy/substrate couples were considered. In order to treat the reaction interface problem effectively, sheets of commercially pure copper (Cu), electrolytic nickel (Ni) and low carbon steel were chosen so that solidification of a Sn-Sb peritectic alloy could be evaluated comprehending very different conditions. A straightforward view of the mechanisms affecting the heat transfer efficiencies was consistent with a number of techniques applied in the present investigation, which includes directional solidification experiments, analytical modelling, wettability analyses and characterization of the reactions between the alloy and the substrates. The proposed analytical model was perceptive to these reactions. For the Cu substrate, the motion of Cu towards the alloy was more effective as compared to the motion of Ni from the Ni substrate. As a consequence, the alloy/Cu interface presented a higher level of Kirkendall voids. The higher fraction of voids at the interface resulted in lower interfacial thermal conductance for the Sn-Sb/Cu couple. Hence, the present experimental-theoretical approach is useful to indicate the solder joint integrity in terms of the presence of empty spots. Despite the higher thermal conductivity of Cu and lower contact angle between the alloy and the Cu in comparison to the Ni substrate, the high porosity at the Cu interface during alloy soldering was shown to reduce the heat transfer capability.

Relation between carriers hopping rate and structural constants in amorphous carbon nickel films with different nickel nanoparticles distributions

In this paper, the films were prepared by radio frequency magnetron co-sputtering technique. The effect of different mosaic targets made of nickel strips and graphite pure on the dielectric relaxation time, the carriers hopping rate, the fractal dimensions and the optical loss of films were studied. The values of the optical band gap of films using the cross-point between the tangent of the plot of lower and higher values of the photon energy were calculated. The films deposited at 4.64% have maximum hopping rate of about 8.6 × 1012 S−1. It can be seen that the films deposited at 3.92% have minimum value of fractal dimension of 2.27. With increasing Ni content of films a nonmetal–metal transition is observed which it is explainable by the power law of percolation theory. Critical metal content and the critical exponent of films were 87.25% and 1, respectively. With increasing Ni content, the carriers effective mass of films decreased and average lattice separation values of films increased. Films deposited at 3.92% have minimum value of Debye frequency νD of about 1.09 × 1012 Hz. The value of energy loss by free charge carriers when traversing the bulk and surface of films at 3.92% has maximum value and it has an increasing function behavior with energy.

Antipoisoning Nickel–Carbon Electrocatalyst for Practical Electrochemical CO2 Reduction to CO

The feasibility of utilizing electrochemical reduction of CO2 (CO2RR) to close the global carbon cycle is hindered by the absence of practical electrocatalysts that can be adopted in large CO2 emit...

Hollow Ni/C microspheres derived from Ni-metal organic framework for electromagnetic wave absorption

Hollow nickel/carbon (Ni/C) microsphere was synthesized by in situ pyrolysis of the Ni-based trimellitic acid framework (Ni-MOF) at argon atmosphere. The morphology of Ni-MOF precursor can be easily controlled by adjusting the volume ratio of DMF and H2O in solvothermal process. When the volume ratio of DMF: H2O is 2: 1, hollow Ni-MOF microspheres can be obtained and the corresponding Ni/C composite exhibits extremely strong electromagnetic wave absorption. The maximum reflection loss is up to −57.25 dB with the matching thickness of only 1.8 mm, while the corresponding effective absorption bandwidth (reflection loss below −10 dB) achieves 5.1 GHz. The excellent electromagnetic wave absorbing capabilities is related to the hollow structure and the synergistic effect between carbon and nickel nanoparticles. This work confirms that the as-prepared Ni/C composite with superior electromagnetic wave absorption properties is a promising candidate for lightweight electromagnetic wave absorbing materials.

Electrospun metal-organic frameworks with polyacrylonitrile as precursors to hierarchical porous carbon and composite nanofibers for adsorption and catalysis

A facile and effective method has been developed to prepare hierarchical porous carbon nanofibers (PCNFs), carbon nanofibers supported nickel nanoparticles (PCNFs-Ni) and carbon nanofibers encapsulating gold nanoparticles (PCNFs-Au). PCNFs or PCNFs-Au were obtained by embedding metal-organic frameworks (e.g. ZIF-8 or ZIF-8-Au) into polyacrylonitrile via electrospinning and subsequent carbonization. In addition, PCNFs-Ni were obtained by impregnating PAN/ZIF-8 nanofibers in Ni(NO3)2·6H2O followed by carbonization. Both PCNF and PCNF–Ni exhibited excellent adsorption activities for methylene blue (MB) and congo red (CR). Especially, PCNF–Ni could be removed and separated via a magnet. PCNFs-Au showed excellent catalytic properties in the reduction reaction of 4-nitrophenol (4-NP).

Study of NiO/CNSs hybrid nanostructure as an electrode material: synthesis and excellent electrochemical performance for application of supercapacitors

A hybrid nanostructure comprising nickel oxide nanoparticles and carbon nanospheres (NiO/CNSs), synthesized via wet chemical process is demonstrated as high-performance electrochemical supercapacitors. The resulting structure exposes that NiO/CNSs electrode possesses irregularly shaped nanoparticles. The NiO/CNSs hybrid nanostructure gives a smaller contact angle of 7° for 6 M KOH electrolyte solution revealing better surface wettability, which enhances the transportation of electrolytic ions into the surface of the electrode material. Furthermore, oscillator strength of Raman active modes confirms the presence of disorder and lower degree of graphitization, which play an important role to improve the electrochemical performance. The NiO/CNSs electrode exhibits a high-specific capacitance of 1380 F g−1 at a current density of 4 A g−1 and long cycle life with 97% charge retention after 1000 cycles. These outcomes reveal that NiO/CNSs can be a promising electrode material for supercapacitors.

Synthesis of carbon nanofibers/poly(para-phenylenediamine)/nickel particles nanocomposite for enhanced methanol electrooxidation

Several studies have been conducted on direct methanol fuel cells (DMFCs) to resolve major issues such as the high cost of the catalyst and the poisoning of the electrode. Herein, a low-cost catalyst based on nickel particles (NiPs), carbon nanofibers (CNF) and poly(para-phenylenediamine) (PpPD) was carried out using a simple electrochemical method. The morphology and structure of the nanocomposite electrodes are characterized by field-emission gun scanning electron microscopy coupled with an energy dispersive X-ray detector, X-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy. The effects of various parameters such as the PpPD film thickness and the NiPs content on the electrocatalytic performance of CPE/CNF/PpPD/NiPs are evaluated which lead to the optimized composition. The results of the methanol electrooxidation reaction at room temperature showed that the optimized CPE/CNF/PpPD/NiPs nanocomposite exhibits a high catalytic activity (Ip = 38.11 mA cm−2), good stability and durability for more than 6 h in comparison with CPE/CNF/NiPs. These findings truly highlight the synergetic effect of CNF/PpPD in enhancing the electrochemical activity and stability and the vast potential of CPE/CNF/PpPD/NiPs as low-cost catalyst and electrodes for DMFCs.

Modelling of a Reversible SOC in Ansys Fluent

Reversible Solid Oxide Cells (SOC) are quite susceptible to variations in operating parameters, and especially the switching of operating modes is not yet well understood. Effects like thermal stress from changes in the current density pattern, as well as carbon deposition and nickel oxidation can destroy SOC. Thus, in order to design a robust SOC system a SOC stack model has been built in ANSYS Fluent 17.0. In this work, this model is used to study the impact of operating mode transition from fuel cell to electrolysis on the stack. It is found that the thermal gradients resulting from switching operation modes are largely depending on the gas compositions fed during both operating modes. Therefore, at fixed operating temperature especially by adjusting the gas feeds thermal gradients can be flattened, so that their effect on the lifetime of the SOC can be significantly reduced.

Carbon black/nickel hybrid filler reinforced conductive polypropylene composites

In current study compatibilized polypropylene filled conductive composites were prepared by melt blending process. A hybrid filler combination at 0.6 to 5 wt% of carbon black and nickel at 50/50 (filler1/filler2) ratio were employed as conducting and reinforcing fillers for polypropylene. Based on quantity of polypropylene in composite, 5 wt% of polypropylene grafted maleic anhydride was utilized for compatibilizing the composite. Melt blending was carried out at 200 °C temperature and 45 rpm rotor speed in a laboratory scale internal mixer. Effect of carbon black and nickel flakes on mechanical, thermal and electrical properties were studied. Electrical conductivity increased with filler loading, whereas mechanical properties increased up to filler loading of 2 wt%. FTIR analysis revealed the presence of compatibilization between metallic fillers and polypropylene. Thermal properties remained unaffected by addition of fillers. SEM micrographs also showed uniform dispersion and distribution of metallic fillers due to better compatibilization provided by polypropylene grafted maleic anhydride.

Electrospun and hydrothermal techniques to synthesize the carbon-coated nickel sulfide microspheres/carbon nanofibers nanocomposite for high performance liquid-state solar cells

To achieve optimal electrochemical performance, a highly efficient and stable noble-metal-free catalyst which consists of carbon-coated nickel sulfide microspheres (Ni3S4@C) and carbon nanofibers (CNFs) are synthesized through the electrospinning and hydrothermal method. The optimized sample provides a large amount of active sites that benefit electron transfer which is further applied as a counter electrode (CE) in dye-sensitized solar cells (DSSCs). A series of electrochemical measurements reveal that the resultant Ni3S4@C/CNFs show higher catalytic activity toward the reduction of I3− to I− in comparison to the benchmark Pt, Ni3S4@C, pure Ni3S4 and CNFs. As a result, the DSSC device assembled with Ni3S4@C/CNFs-based CE affords a decent power conversion efficiency (PCE) of 8.29%, which surpasses the corresponding values of the device using the commercial Pt (7.35%), Ni3S4@C(6.81%), pure Ni3S4(6.51%) and CNFs (6.11%) CE under identical conditions. This work unfolds a new strategy for developing low-cost and effective CE materials in DSSCs.

Electrical, mechanical and dynamic properties of ternary composites from acrylonitrile butadiene rubber and conductive fillers

This paper presents comparative investigations on dual and ternary composites based on nitrile butadiene rubber. These composites were filled with carbon black and nickel powder at various ratios with each filler or with a combination of both. The focus of this study is on the electrical, mechanical and dynamic properties of the materials as influenced by the loading rate, applied pressure and bending degree have on the specific volume electrical resistivity. The investigations of the dynamic properties view the effect that the amount and chemical nature of the fillers have on the storage modulus and the tangent of the mechanical loss angle. It has been established that the specific characteristics of each of the fillers (particle size, specific surface, tendency to aggregate and agglomerate, interaction with the elastomeric matrix) have the greatest impact on composite properties. Scanning electron microscopy studies of the fillers and composites also confirm the results obtained.

Noble Metal-Free Photocatalysts Consisting of Graphitic Carbon Nitride, Nickel Complex, and Nickel Oxide Nanoparticles for Efficient Hydrogen Generation.

A facile and simple synthetic route is developed to prepare earth-abundant and noble metal-free hybrid photocatalysts, which are composed of graphitic carbon nitride (CN), nickel complex, and NiO x nanoparticles. Bimolecular nucleophilic substitution reaction was employed to attach a nickel complex onto a graphitic CN framework through covalent bonds to support its high loading and dispersion. NiO x nanoparticles were further incorporated into the catalysts to serve as a hole-transporting medium to improve the separation of photogenerated carriers for higher photocatalytic activity. Both yNiL/CN and yNiL/NiO x/CN exhibit superb H2 evolution activity. The optimum H2 evolution rate of the binary photocatalysts yNiL/CN reaches 303.3 μmol·h-1·g-1, whereas that of the ternary photocatalysts yNiL/NiO x/CN reaches 524.1 μmol·h-1·g-1, and the apparent quantum efficiency reaches 1.46% at 450 nm. This finding reveals that coordination of a nickel complex is significant in promoting photocatalytic performance, and the incorporation of NiO x nanoparticles as a hole-transporting medium is beneficial for separation of the photogenerated charge carriers. The novel hybrid system offers a new horizon for designing transition-metal complex-modified graphitic CN as noble metal-free and highly active photocatalysts for efficient visible light-driven hydrogen generation.

Electrochemically Activated Nickel-Carbon Composite as Ultrastable Cathodes for Rechargeable Nickel-Zinc Batteries.

Aqueous rechargeable nickel-zinc batteries are highly attractive for large-scale energy storage for their high output voltage, low cost, and excellent safety; however, their inferior cycling durability due to the degradation of the Ni-based cathode is a major obstacle for their applications. In this context, we develop a new kind of porous electrochemically activated Ni nanoparticle/nitrogen-doped carbon (Ni/NC) composite material as ultrastable cathodes for advanced aqueous rechargeable nickel-zinc batteries. The in situ formation of a highly active NiO x(OH) y layer on Ni nanoparticles and a unique hydrophilic porous architecture endow the activated Ni/NC composite with high accessible area, abundant active sites, easy electrolyte permeation, and shortened charge/ion transport pathway. Consequently, a high capacity of 381.2 μAh cm-3 with an outstanding rate capability is achieved by the Ni-Zn battery using the optimized activated Ni/NC composite as the cathode (about 30-fold enhancement compared to that with the pristine Ni/NC composite as the cathode). More impressively, the as-assembled Ni-Zn battery achieves an unprecedented cyclic stability with no capacity loss after 36 000 charge/discharge cycles. This is the highest cyclic durability ever for Ni-Zn batteries and other aqueous rechargeable batteries. This novel efficient electrochemical activation strategy to achieve a high-performance cathode and demonstration of an ultrastable aqueous rechargeable Ni-Zn battery may open up new vistas on the development of more advanced and reliable energy storage materials and devices.

Potential Corrosion Issue in CO2 Pipeline

In this paper we investigate the increasing atmospheric concentration of carbon dioxide originating from human activities which include burning fossil fuels for heat and electricity generation, and combustion of other fuels in industry lead to greenhouse gases (GHG) mainly CO 2 which has an impact on the global climate warming. It is necessary to scale down the impact of these gases on the global climate by minimizing or preventing greenhouse gas emission to the atmosphere. Carbon capture and storage (CCS) from the source or power plant will help in reducing the emission of CO 2 from the atmosphere with the means of transporting the gas through the pipeline from the captured sources or power plant to storage sites underground or for enhanced oil recovery (EOR). However, this gas has some contaminant or impurities which affect the mechanical and chemical properties of the pipeline system during transportation. This paper examines various contaminants such as CO 2, H 2 S, CO, NO X , SO X , and H 2 O in carbon dioxide transmission pipelines with a particular focus on assessing how the contaminants causes corrosion in the pipeline and also considered materials that can be used as alternative to carbon steel for CO 2 transportation pipeline. The materials examined ranges from weldable 13%Cr super modified martensitic stainless steel, 22%Cr duplex and 25% Cr super duplex stainless steel, 316L clad pipe or Lined carbon steel and nickel alloy, and some parameters in materials selection were examined. The alternative materials considered are 13 %Cr super-modified martensitic stainless steel, and 25 %Cr super-duplex stainless steel. Keywords: CO 2 Corrosion, CO 2 Contaminant, Material Selection. DOI : 10.7176/JEP/10-12-19 Publication date : April 30 th 2019

Nanoparticle-Enhanced Laser Induced Breakdown Spectroscopy Using Copper–Silver and Nickel–Carbon Nanocomposites on Aluminium

Composite Ag–Cu and Ni–C nanoparticles were synthesized by laser ablation and spark discharge in liquid, respectively. An amplification of the signal during laser induced breakdown spectroscopy was observed after deposition of the nanoparticles on the surface of an aluminum foil. The emission intensity of the laser plume increased from 2 to 20 times depending on the spectral lines used for the measurements. The intensity growth was higher for Ag–Cu nanoparticles.

Holey nickel nanotube reticular network scaffold for high-performance flexible rechargeable Zn/MnO2 batteries

Developing uniform and interconnected conductive networks is critically important for future electrochemical electrodes. Reticular holey metallic nanotube networks can be a competitive candidate for this purpose, taking the advantages of a large surface area (both inner and outer surface can host active material) and excellent mechanical flexibility. However, due to the limited available fabrication techniques, there have not been any report regarding the controllable and large-scale fabrication of such a structure. Herein, we report an industry-compatible fabrication method for highly interconnected and conductive network of holey nickel nanotube membrane (HNNM) for electrode conductive scaffold, which is highly conducive for mass and charge transfer and shows superior mechanical flexibility. The as-obtained HNNM presents a high surface area of 8.67 m2 g−1 and conductivity (∼10-1 Ω/□ with the thickness of 15 μm), which is superior than those of nickel foam, carbon cloth and stainless-steel mesh etc. By electrodepositing a thin layer of MnO2 on HNNM (HNNM@MnO2) as cathode, and Zn metal on HNNM (HNNM@Zn) as anode, an aqueous flexible rechargeable Zn/MnO2 battery was successfully assembled with a capacity of 275.5 mA h g−1 at 0.2 A g−1 and a working voltage of 1.38 V. Moreover, it achieves an energy density of 380.19 Wh kg−1 with a maximum power density of 1.38 kW kg−1 and a high capacity retention after 500 cycles, which represents a critical step forward toward environmentally benign, low cost, and high performance electrochemical energy storage for practical applications.