Surface Of Ni Foam Research Articles

Samarium oxide modified Ni-Co nanosheets based three-dimensional honeycomb film on nickel foam: A highly efficient electrocatalyst for hydrogen evolution reaction

The development of highly efficient and stable noble-metal-free electrocatalysts towards HER is of great significance. Herein, an electrodeposition method for the preparation of samarium oxide modified Ni-Co vertical nanosheets assembled three-dimensional honeycomb film on porous Ni foam (Sm2O3-Ni-Co/NF) is proposed. As-prepared Sm2O3-Ni-Co vertical nanosheets interweave together into a honeycomb morphology and uniformly cover the entire surface of Ni foam. The influence of content of Sm2O3 in electroplating bath on the electrocatalytic performances of Sm2O3-Ni-Co/NF electrode towards HER is studied in 1.0 M KOH electrolyte. Polarization curve indicates that the self-supported Sm2O3-Ni-Co/NF electrode exhibits remarkably enhanced electrocatalytic activity towards HER. To attain a current density of 10 mA cm−2, Sm2O3-Ni-Co/NF electrode needs lower overpotential (276 mV) than Ni-Co/NF electrode (301 mV). In addition, Sm2O3-Ni-Co/NF electrode exhibits a lower Tafel slope, demonstrating more favorable HER kinetics. Sm2O3-Ni-Co/NF electrode has smaller charge transfer resistance than Ni-Co/NF electrode, indicating a faster Faradic process and better HER kinetics. Besides, Sm2O3-Ni-Co/NF electrode features satisfactory long-term durability in alkaline media. The results indicate that Sm2O3-Ni-Co/NF electrode has potential application to water splitting devices for hydrogen generation.

MnO2/ZnCo2O4 with binder-free arrays on nickel foam loaded with graphene as a high performance electrode for advanced asymmetric supercapacitors.

ZnCo2O4 nanosheets were successfully arrayed on a Ni foam surface with graphene using a hydrothermal method followed by annealing treatment; then MnO2 nanoparticles were electrodeposited on the ZnCo2O4 nanosheets to obtain a synthesized composite binder-free electrode named MnO2/ZnCo2O4/graphene/Ni foam (denoted as MnO2/ZnCo2O4/G/NF). After testing the binder-free composite electrode of MnO2/ZnCo2O4/G/NF via cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy testing, we found that it exhibited ultrahigh electrochemical properties, with a high specific areal capacitance of 3405.21 F g−1 under a current density of 2 A g−1, and wonderful cycling stability, with 91.2% retention after 5000 cycles. Moreover, an asymmetric supercapacitor (ASC) based on MnO2/ZnCo2O4/G/NF//G/NF was successfully designed. When tested, the as-designed ASC can achieve a maximum energy density of 46.85 W h kg−1 at a power density of 166.67 W kg−1. Finally, the ASC we assembled can power a commercial red LED lamp successfully for more than 5 min, which proves its practicability. All these impressive performances indicate that the MnO2/ZnCo2O4/graphene composite material is an outstanding electrode material for electrochemical capacitors.

Mn (OH)2 electrodeposited on secondary porous Ni nano-architecture foam as high-performance electrode for supercapacitors

The preparation and capacitance performances of Mn (OH)2@ secondary porous Ni nano-architecture foam (Mn (OH)2@SPNiNF) hybrids are systematically studied. The SPNiNF structure is simply obtained via a NiC2O4·2H2O in situ growing process on Ni foam surface, combined with a thermally treated process under Ar gas. Then, a layer of Mn (OH)2 film was electrodeposited onto the above SPNiNF sheet by applying a galvanostatical technique. It is shown that the SPNiNF sheet is composed of interconnected nanoparticles with a diameter range of 100–200 nm. The fabricated Mn (OH)2@SPNiNF electrode exhibited a high specific capacitance of 532.7 F g−1 and an areal capacitance of 906 m F cm−2 at a current density of 0.5 A g−1. The Mn (OH)2@SPNiNF electrode also exhibited a low ions diffusion resistance and a good cycling performance along with 85.7% specific capacitance retained after 5000 cycles. An asymmetric Mn (OH)2@SPNiNF //AC super capacitor exhibited an energy density of 69.1 Wh kg−1 at a power density of 0.6 kW kg−1. These results demonstrated that the Mn (OH)2@SPNiNF was a promising electrode material for supercapacitors.

Copper tungsten sulfide anchored on Ni-foam as a high-performance binder free negative electrode for asymmetric supercapacitor

Transition binary metal sulfides have fascinated much attention as electrode materials for energy storage applications. Herein, we report the use of binder-free copper tungsten sulfide (CWS) anchored on Ni foam and investigated its electrochemical properties as a negative electrode for supercapacitor application. The mechanism of CWS growth on the surface of Ni foam via hydrothermal process is explained based on recrystallization of metastable precursors (RMP) process and confirmed using laser Raman spectroscopic analysis. The electrochemical analysis using three-electrode configuration reveals that the charge-storage mechanism is due to the Type-B pseudocapacitance (due to intercalation with partial redox) nature of the CWS/Ni electrode with a high specific capacitance (areal capacitance/specific capacity) of 2666.6 F g−1 (888.8 mAh g−1/1866.6 mF cm−2) at a constant current of 10 mA. To emphasize the potential use of CWS/Ni electrode in energy storage sector, we fabricated an asymmetric supercapacitor device using CWS/Ni (negative electrode) and graphene (positive electrode) which delivers a device specific capacitance (107.93 F g−1/226.67 mF cm−2) with a high energy density (48.57 Wh kg−1/102 μWh cm−2), and excellent electrochemical stability for 10,000 charge-discharge cycles. These results confirm that the CWS/Ni electrode can act as an effective energy-storage electrode material for high performance supercapacitors.

TiO2 sol/graphene modified 3D porous Ni foam: A novel platform for enzymatic electrochemical biosensor

An integrated system based on nickel foam (Ni foam), titanium dioxide sol/graphene nanocomposite and lactate oxidase (LOx) has been successfully developed for the sensing of lactate. A TiO2/graphene nanocomposite was readily synthesized and coated on a 3D porous Ni foam electrode to develop a novel electrode in an electrochemical biosensor. The as-prepared nanocomposite and the modified Ni foam were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) to verify the well intercalation of graphene within TiO2 sol and successful coating of such nanocomposite on Ni foam surface, respectively. Comparing with an unmodified Ni foam, TiO2 sol/graphene modified Ni foam offered a drastic increase in current response signal (a 28-fold) toward H2O2 detection, suggesting a potential application of this system as a sensitive electrochemical sensor. Then, LOx was immobilized onto the modified electrode for lactate sensor via H2O2 detection. Interestingly, the combination between graphene and TiO2 sol enhanced both sensitivity and stability of this sensor. A wide linear range of 50μM to 10mM with a detection limit of 19μM was obtained for lactate without interfering effect from ascorbic acid, dopamine, and glucose. This platform was sensitive enough for early diagnosis of severe sepsis and septic shock via the detection of concerned lactate level. Eventually, it was successfully applied to detection of lactate in a complex biological fluid.

A facile electrodeposition technique for synthesis of nickel sulfides/carbon nanotubes nanocomposites as high performance electrodes for supercapacitor

We reported a facile and easily controllable electrodeposition-and-ion exchange technique for synthesis of Ni3S2/carbon nanotubes (CNTs) nanocomposites on the surface of Ni foam for supercapacitor applications. When tested as electrode for a supercapacitor, a large surface area of the Ni3S2/CNTs hybrid nanoarchitecture was proven and it showed an excellent specific capacitance of 1643 F/g at the current density of 1 A/g, and maintains 999 F/g at 20 A/g. The Ni3S2/CNTs electrode also displayed good cycle stability with capacitance retention of 91.5% after 2000 cycles in 3 M KOH electrolyte. Because of these outstanding properties, the Ni3S2/CNTs nanocomposites are becoming promising candidates for the high performance binder-free supercapacitor electrodes.

Electrochemical reduction of nitrate via Cu/Ni composite cathode paired with Ir-Ru/Ti anode: High efficiency and N2 selectivity

To address the severe nitrate contamination of water sources, a Cu/Ni bimetallic composite electrode was successfully prepared via cathodic electrodeposition method. Characterization by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction confirmed that Cu nanoparticles were successfully deposited on the surface of Ni foam as irregular spherical structures with a diameters of 900 nm. The Cu/Ni electrode was applied as a cathode in nitrate electroreduction experiments, achieving nearly complete removal of nitrate within 60 min compared to a Ni foam electrode (15.0% removal). The improved performance was attributed to the dramatically increased catalytically active sites and the decreased resistance of the electrode, as shown by linear sweep voltammetry and electrochemical impedance spectroscopy analyses. The parameters influencing electrolysis, including current density, Cl− concentration, and solution pH were evaluated. It was concluded that (a) Increasing the current density favored nitrate removal, but reduced the electronic energy utilization efficiency; (b) Cl− presence hindered nitrate removal slightly, but facilitated NH4+-N removal significantly; (c) Acidic conditions were detrimental to nitrate and total nitrogen removal. Additionally, reusability experiments of the Cu/Ni electrode over eight cycles were performed. These indicated that the Cu/Ni electrode possessed excellent stability, maintaining a high removal efficiency of >95.0% over eight cycles. Finally, a possible removal pathway of nitrate electroreduction with the Cu/Ni cathode was proposed.

Electrochemical Study of Graphene Coated Nickel Foam as an Anode for Lithium-Ion Battery

This study reports the synthesis of a few-layered graphene (GF) thin film on Ni foam by chemical vapor deposition (CVD) technique and investigation of its electrochemical performance as a negative electrode for lithium-ion batteries (LIBs). A standard deposition procedure with a methane precursor was employed to prepare the GF films. The SEM studies revealed the formation of a dark uniform film on the surface of Ni foam’s wires upon the CVD deposition. The film consisted of numerous GF sheets replicating the shape of the Ni grain boundaries over the Ni wire surface. The Raman spectroscopy of the prepared films on the Ni foam confirmed that the samples are a few-layered GF with high quality and purity. In order to evaluate the potential of the use of the prepared materials as an anode in LIBs, their electrochemical performance was studied in coin-type lithium half-cells using cyclic voltammetry (CV) and galvanostatic cycling. The results of CV showed that both graphene and native oxide layer (NiO) on nickel foam exhibit electrochemical activity with respect to lithium ions. Galvanostatic cycling revealed that both GF and NiO contribute to the overall capacity, which increases upon cycling with a stable Coulombic efficiency of around 99%. The designed 3D GF coated NiO/Ni anode demonstrated a gradual increase of its areal charge capacity from 65 μAh cm-2 at the initial cycle to 250 μAh cm-2 at the final 250th cycle.

Facile synthesis of hexagonal single-crystalline ZnCo2O4 nanosheet arrays assembled by mesoporous nanosheets as electrodes for high-performance electrochemical capacitors and gas sensors

A facile strategy has been developed to realize the controllable synthesis of two dimensional (2D) single crystalline ZnCo2O4 nanosheet arrays (h-ZCO NSs) on the Ni foam surface. According to the SEM, TEM and BET analysis, it was found that the h-ZCO NSs have a hexagonal structure with a thickness of ca. 84 nm, and display a high specific surface area of 94.1 m2 g–1 with the pore size distribution of ca. 8 nm. As electrochemical capacitor electrode, h-ZCO NSs show large specific capacitance (1004.9 F g−1 at 3.3 A g–1), good rate capability and excellent cycling stability (93.5% capacitance retention after 2000 cycles at 10.0 A g–1), indicating better electrochemical performance. Additionally, serving as a gas sensor, h-ZCO NSs also exhibit remarkable sensitivity and selectivity towards methanol gas. All these impressive performances suggest that the h-ZCO NSs are a promising electrode material for electrochemical capacitors and gas sensors.

The high performance mushroom-like Pd@SnO2/Ni foam electrode for H2O2 reduction in alkaline media

A novel mushroom-like electrode (Pd@SnO2/Ni foam) is designed and prepared through two step method including of a simple hydrothermal process and an electrodeposition technology. Rutile SnO2 nanorod arrays grow vertically on the Ni foam surface with diameters of around 40 nm, lengths up to around 300 nm and Pd nanoparticles decorate on the top of SnO2 nanorods to form a mushroom-like electrode structure with SnO2 as stem and Pd nanoparticles as mushroom head. The Pd@SnO2/Ni foam electrode exhibits superior catalytic activity and excellent stability at the higher concentration of hydrogen peroxide(H2O2). The reduction current density achieves successfully 320 mA cm−2 at −0.54 V, and it changes barely during 800 potential cycles in 0.5 mol L−1 H2O2 + 3.0 mol L−1 NaOH. The improved performance suggests its promising application as an efficient electrode for H2O2-based fuel cells.

Electrodegradation of Resorcinol on Pure and Catalyst-Modified Ni Foam Anodes, Studied under Alkaline and Neutral pH Conditions.

This work reports on the kinetics of electrochemical degradation of the resorcinol molecule, examined on nickel foam-based electrodes in contact with 0.1 M NaOH and 0.5 M Na2SO4 supporting electrolytes. The electrooxidation of resorcinol was examined on as-received, as well as on Pd-modified, nickel foam catalyst materials, produced via spontaneous deposition of trace amounts of palladium element. Electrochemical (cyclic voltammetry and a.c. impedance) experiments were carried out by means of a three-compartment, pyrex glass electrochemical cell, whereas continuous resorcinol electrooxidation tests were conducted galvanostatically (or potentistatically) with a laboratory-size, single-cell electrolyzer unit. In addition, quantitative determination of resorcinol and its possible electrodegradation products was performed by means of instrumental HPLC: High-Performance Liquid Chromatography/MS: Mass Spectrometry methodology. Also, SEM (Scanning Electron Microscopy) and EDX (Energy Dispersive X-ray spectroscopy) techniques were employed for Ni foam (Pd-modified Ni foam) surface characterizations.

All-solid-state, flexible, ultrahigh performance supercapacitors based on the Ni-Al LDH-rGO electrodes

In this work, we investigate the application of Ni-Al LDH-rGO composite directly synthesized on nickel foam by a low cost and facile CV electrodeposition method as a new electrode for all-solid-state flexible supercapacitors. Due to the synergistic effects between the Ni-Al LDH and the graphene sheets, directly grown on the surface of Ni foam, the as prepared electrodes exhibit an ultrahigh specific capacitance of 2693.25 F g−1 at a current density of 2 A g−1. When these electrodes are used in asymmetric (Ni-Al LDH-rGO//Fe2O3-rGO) and symmetric (Ni-Al LDH-rGO//Ni-Al LDH-rGO) all-solid-stat supercapacitors, the as-prepared devices show excellent flexibility with a maximum specific capacitance and energy density of 214.4 F g−1 and 76.23 Wh Kg−1 for asymmetric device, and 412.30 F g−1 and 36.65 Wh Kg−1 for symmetric device.

Engineering hierarchical ultrathin CuCo2O4 nanosheets array on Ni foam by rapid electrodeposition method toward high-performance binder-free supercapacitors

In the present work, we engineer hierarchical ultrathin CuCo2O4 nanosheets arrays on Ni foam through a facile, controllable and low-cost electrodeposition method by controlling deposition time and adjusting precursor’s type, as a binder-free electrode for high performance supercapacitors. The effects of deposition time and types of precursors on the morphology of the as-prepared electrodes were investigated by X-ray diffraction, energy dispersive X-ray analysis, field-emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. As a results, the CuCo2O4 electrode prepared by nitrate salts at the deposition time of 10 min, includes the most uniform and ultrathin nanosheet arrays and exhibits the highest capacitance performance, such as ultrahigh specific capacitance of 1330 F g−1 at 2 A g−1 with 70% capacitance retention (938 F g−1) at ultrahigh current density of 60 A g−1, excellent cycling stability of 93.6% capacitance retention after 5000CD cycles and the maximum energy density of 29.55 Wh kg−1 at the power density of 0.4 kW kg−1. These superior electrochemical performances have been attributed to its unique structures with direct connected ultrathin nanosheets on the surface of Ni foam and abundant pores provide large electroactive sites for electrochemical reactions, as well as facile electron, ion transport and high electrical conductivity.

Formation of SnS2/Ni2S3 heterojunction on three-dimensional nickelframework for treating chromium(VI)-containing wastewater

Heterojunction system, as a considerable method, has been proved a good solution to improve photocatalysis. Herein, a novel SnS2/Ni3S2 heterojunction deposited on Ni foam (NF) (SnS2/Ni3S2@NF) has been successfully synthesized by hydrothermal method. The photocatalytic activity has been improved due to the special heterostructure. Scanning electron microscopy, x-ray diffraction, Raman, UV–vis diffuse reflectance spectroscopy and photocatalytic test were employed to prove it. The SEM pictures showed that the surface of NF deposited a certain amount of SnS2/Ni3S2. And SnS2/Ni3S2@NF heterojunction photocatalyst exhibits an excellent catalytic ability in the visible light region. Compared to pristine SnS2, the as-prepared SnS2/Ni3S2@NF heterojunction showed increased photocatalytic activity toward Cr(VI) photoreduction under visible light irradiation. This work will be useful for the design of other photocatalyst for application in Cr(VI) removal.

Heterooctamolybdate-Based Clusters H3[(Cp*Rh)4PMo8O32] and H5[Na2(Cp*Ir)4PMo8O34] and Derived Hybrid Nanomaterials with Efficient Electrocatalytic Hydrogen Evolution Reaction Activity.

Polyoxometalates (POMs), emerging as a new class of porous molecular materials, play a promising role in homo- and heterogeneous catalysis. Among them, noble-metal-decorated POMs have a profound impact as catalytic materials. Thus, it is imperative to design and structurally explore new catalysts including noble metals. Herein, two new clusters, H3[(Cp*Rh)4PMo8O32]·14H2O (1) and H5[Na2(Cp*Ir)4PMo8O34]·13H2O (2) (Cp* = pentamethylcyclopentadienyl), based on a heterooctamolybdate anionic core were successfully obtained via a one-pot reaction using [Cp*MCl2]2 [M = Rh (1) and Ir (2)] and Na2MoO4 in acidic conditions. Compounds 1 and 2 were well characterized in the solid state by single-crystal X-ray diffraction, IR, and thermogravimetric analysis and in solution by UV-vis, electrospray ionization mass spectrometry, and electrochemistry. Compounds 1 and 2 represent an important class of structurally isolated organometallic POM-based clusters that were successfully nanostructured onto Ni foam and electrochemically reduced after 48 h of electrolysis to M/MoO2, where M = Rh (3) and Ir (4), nanocomposite hybrid materials on a Ni foam surface in a 0.1 M KOH solution. The modified electrocatalysts (3 and 4) show efficient hydrogen evolution reaction activities almost comparable to those of high-grade Pt/C at 0.1 M KOH. The nanostructured POMs [1- and 2@NF (Ni foam)] and their corresponding reduced products (3 and 4) were observed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy and further proven by transmission electron microscopy (TEM) and high-resolution TEM.

Room-temperature synthesis of NiS hollow spheres on nickel foam for high-performance supercapacitor electrodes

NiS hollow spheres were synthesized directly on the surface of Ni foam (NiS@NF) at room temperature via a simple electrodeposition in a KOH/thiourea solution without any Ni precursors. Morphological analysis revealed the formation of NiS hollow spheres, which consisted of nanoparticles. The NiS@NF nanocomposite exhibited a very high specific capacitance of 1553Fg−1 (2.64Fcm−2) at a current density of 2.35Ag−1 (4mAcm−2) in 6M KOH electrolyte. The NiS@NF nanocomposite also demonstrated excellent cycling stability (95.7% specific capacitance retention after 2000 cycles).

Permeability studies on 3D Ni foam/graphene composites

This study investigates the permeability of new 3D Ni foam/graphene composites (Ni foam covered with graphene) using compressed air, Ar and N2 as the probe gases. The results show that the introduction of graphene on the surface of Ni foam via in situ chemical vapour deposition is not detrimental to the permeability of the composites; on the contrary, in some cases it improves permeability. A modified Ergun-type correlation has been proposed, which represents very well the permeability of the Ni foam/graphene composites, especially at flow rates higher than 0.3 m s−1. Further studies show that graphene also helps to improve the thermal conductivity of the composite. These results suggest that the graphene involvement will make the Ni foam/graphene composite a good candidate for potential applications such as filters or heat exchangers suitable for working under harsh conditions such as at high temperatures, in corrosive environments, etc.

The effect of graphene coated nickel foam on the microstructures of NiO and their supercapacitor performance

Cotton-like NiO is formed on the surface of bare Ni foam after hydrothermal process and calcination process, while ultrathin NiO nanoflakes occur on Ni foam coated with graphene. The high specific capacitance of 1782Fg−1 at 1Ag−1 and 90.2% capacity retention at 1Ag−1 after 5000cycles charge-discharge test are found. The graphene induces the high electrical conductivity and excellent interfacial contact, in addition, the graphene facilitates the forming of ultrathin NiO nanoflakes which result in huge pseudocapacitance due to large surface area and abundant mesoporous. The unique microstructure characteristic promotes interfacial electron transport in the electrode material and improves ion diffusion during the electrochemical reaction process.

Comparing different microstructures of CoS formed on bare Ni foam and Ni foam coated graphene and their supercapacitors performance

Few layer graphene was formed on the surface of Ni foam using the chemical vapor deposition technique, which effectively decreased flaws and inhibited stack of graphene. The CoS nanorods were synthesized on the surface of bare Ni foam after hydrothermal method, while graphen on Ni foam facilitated to form CoS nanowires with porosity surface structure and large specific surface area. The CoS nanowires on Ni foam coated with graphene showed an high specific capacitance of 1506Fg−1 at 1Ag−1 and 88.2% capacity retention at a current density of 1Ag−1 after 5000 cycles charge-discharge test. The improved electronic conductivity of current collector Ni foam by graphene and porous microstructure of CoS nanowires catalyzed by graphene enhanced significantly supercapacitors performance. This was attributed to large CoS nanowires electrode-electrolyte contact area and reduced volume change during the charge-discharge process.

Investigation of microstructures of ZnCo2O4 on bare Ni foam and Ni foam coated with graphene and their supercapacitors performance

The graphene coating was deposited on the surface of Ni foam using the chemical vapor deposition process. A large amount of flower-like ZnCo2O4 microspheres with short nanowires were formed on bare Ni foam by hydrothermal method, while large-scale ZnCo2O4 nanowires arrays homogeneously aligned and separated adequately on Ni foam coated with graphene. This ZnCo2O4 nanowire structure exhibited superior supercapacitors properties. The excellent supercapacitors were mainly attributed to the large specific surface and the porosity on the nanowires which promoted the electrons and ions transportation. In addition, graphene improved conductivity of substrate for current collecting.