Electrode For Hydrogen Evolution Reaction Research Articles

MoS2 nanoflower-decorated reduced graphene oxide paper for high-performance hydrogen evolution reaction.

A facile, one-pot solvothermal method is developed to synthesize MoS2 nanoflowers (MoS2NFs) coated on reduced graphene oxide (rGO) paper. The resulting MoS2NF/rGO paper serves as a freestanding, flexible and durable working electrode for hydrogen evolution reaction (HER), exhibiting an overpotential lowered to -0.19 V with a Tafel slope of ∼95 mV per decade.

Electrocatalytic activity of Ni–Fe–M (M = Cr, Mn, Cu) sintered electrodes for hydrogen evolution reaction in alkaline solution

Ternary Ni60Fe30M10 (M=Cr, Mn, Cu) sintered alloys have been characterized by means of microstructural and electrochemical techniques in view of their possible applications as electrocatalytic materials for hydrogen evolution reaction (HER). Well-mixed powders of nickel, iron and copper, manganese, or chromium were pressed together under high pressure at room temperature and then sintered in vacuum at high temperature. The surface morphology of the alloys was examined by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDXS). The electrochemical efficiency of the electrodes has been studied on the basis of electrochemical data obtained from steady-state polarization and electrochemical impedance spectroscopy (EIS) techniques in 1M NaOH solution at 298K. The results were compared with those obtained on binary Ni60Fe40 sintered alloy. The overall experimental data indicate that alloying Ni–Fe with Cr, Mn and Cu leads to an increase of electrocatalytic activity in hydrogen evolution with respect to the Ni60Fe40 electrode. High catalytic efficiencies were achieved on Ni60Fe30Mn10 and Ni60Fe30Cr10 electrodes, the latter being the best electrocatalyst for the HER.

Development of Fe2O3–TiO2 mixed oxide incorporated Ni–P coating for electrocatalytic hydrogen evolution reaction

Considering the electronic parameters and chemical characteristics, a synergistic catalytic effect of Fe2O3 along with TiO2 could be achieved for electrochemical reactions if both the oxides are produced in a mixed oxide form. The present study explored the mixed oxide composite viz; Fe2O3–TiO2, synthesized via thermal decomposition method, to increase the catalytic efficiency of Ni–P electrodes, the well known catalytic electrodes for hydrogen evolution reaction in alkaline medium. The incorporation of the Fe2O3–TiO2 mixed oxide into Ni–P matrix substantially reduced overpotential during hydrogen evolution reaction (HER) in 32% NaOH solution. A significant improvement on the electrochemical activity of the Ni–P coated electrodes was achieved as evidenced from the results of Tafel and impedance studies. The incorporation of Fe2O3–TiO2 mixed oxide composite into the Ni–P matrix has improved both metallurgical and electrochemical characteristics and hence its amount of incorporation should be optimum. The electrodes exhibited high stability under dynamic experimental conditions. The role of the composite and the possible mechanism are discussed in this paper.

High electrocatalytic effect of Au–Pd alloy nanoparticles electrodeposited on microwave assisted sol–gel-derived carbon ceramic electrode for hydrogen evolution reaction

Various Au–Pd bimetallic nanoparticles were electrodeposited on microwave irradiated carbon ceramic electrodes (MWCCE). Au:Pd molar ratios of 75:25, 50:50 and 25:75 were electrodeposited on MWCCE and their electrocatalytic activities for hydrogen evolution reaction (HER) were evaluated. Among them, the alloy with Au:Pd molar ratio of 25:75 showed highest electrocatalytic activity for HER. The structure and nature of these alloys were characterized by scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, inductively coupled plasma, and cyclic voltammetry. Alloying degree of bimetallic nanoparticles and electrodeposition time were optimized. The electrocatalytic activity of bimetallic nanoparticles was also compared with individual non-alloyed Au and Pd catalysts and the results showed that alloy nanoparticles have higher electrocatalytic activity for hydrogen evolution. The Tafel slopes ranges are obtained from 136 mV dec−1 to 165 mV dec−1 for HER on bare and modified MWCCE and kinetic parameters show that the Volmer step must control the HER. The stability of the best electrode is determined by chronopotentiometric and it showed a good stability.

Electrochemical synthesis of Ni–S/CeO2 composite electrodes for hydrogen evolution reaction

Ni–S/CeO2 electrodes have been prepared by a composite electrodeposition technique using nickel sulfaminate bath containing suspended micro- or nano-sized CeO2 particles. The composite electrodes exhibit a high activity for the hydrogen evolution reaction (HER) in alkaline solutions, most likely due to the synergistic effects between Ni and CeO2, as well as the increased surface area of the electrodes upon addition of CeO2 particles. It is found that the addition of CeO2 particles can lead to an increase of the sulphur content, resulting in more amorphous structures in the composite coatings. The Ni–S/micro-CeO2 composite electrode yields a higher HER activity than that measured with Ni–S/nano-CeO2 electrode, which is 2.2 times higher than that on the Ni–S coating. The relevant discussion was provided to elucidate the promotional roles of CeO2 particles in the composite electrodeposition process and corresponding HER activity.

One-step electroless deposition of Pd/Pt bimetallic microstructures by galvanic replacement on copper substrate and investigation of its performance for the hydrogen evolution reaction

A facile and one-step method for fabrication of Pd/Pt bimetallic microstructure using galvanic replacement reaction is presented. This electroless deposition was performed without any additive reagent via simple immersion of the copper sheet in cation aqueous solution of Pd and Pt. The as-prepared electrode was characterized by using the techniques of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and cyclic voltammetry and tested for the hydrogen evolution reaction (HER) in the acidic media. Comparison of the HER on the Pd/Pt bimetallic catalysts with different Pd:Pt percentage compositions indicated that the Pd60Pt40 catalyst had the highest HER activity among all the Pd/Pt catalysts and a better performance than the pure Pt. The effects of galvanic replacement time and concentration of H2SO4 on the catalytic activity of as-prepared electrode for HER were comparatively investigated.

Comparison of four nickel-based electrodes for hydrogen evolution reaction

Hydrogen evolution reaction was investigated in 0.50M Na2SO4+0.10M H2SO4 solution at room temperature on four types of nickel-based electrodes: (I) pure nickel electrode electrodeposited in acid solution (pH 4.0), (II) pure nickel electrode electrodeposited in ammoniacal solution (pH 9.0), (III) nickel/zeolite electrode co-deposited in ammoniacal solution containing zeolite particles and (IV) porous nickel electrode obtained by leaching out zeolite particles from nickel/zeolite electrode. The morphology and the microstructure of four types of electrodes were characterized by scanning electron microscopy and X-ray diffraction, and the electrocatalytic efficiency was evaluated based on steady-state polarization curves, Tafel plots and electrochemical impedance spectroscopy. It was shown that the electrocatalytic activity of as prepared electrodes depended on the morphology and the microstructure and, especially, the porous nickel electrode has the lowest charge transfer resistance, the highest exchange current density and electrocatalytic activity compared to the others for hydrogen evolution reaction.

Ni–CeO2 composite cathode material for hydrogen evolution reaction in alkaline electrolyte

In this work, nickel-based electrodes were prepared using composite electrodeposition technique in a nickel sulphamate bath containing suspended micro- or nano-sized CeO2 particles. The prepared Ni–CeO2 composite electrodes exhibit an enhanced high catalytic activity toward hydrogen evolution reaction (HER) in alkaline solutions. X-ray diffraction patterns indicated that the CeO2 particles have been successfully incorporated into the Ni matrix and altered the texture coefficient (TC) of the Ni layer. The morphology of the obtained coatings was characterized by Scanning Electron Microscopy, and the CeO2 content was determined by coupled energy dispersive X-ray spectrometry. The thermal stability of the composite electrodes was analyzed by thermogravimetric and differential scanning calorimetry, showing a good thermal stability. The catalytic activity of the composite electrodes for HER was measured by steady-state polarization and electrochemical impedance spectroscopy techniques in 1.0 M NaOH solution at room temperature. The exchange current density of HER on the Ni–CeO2 composite electrodes was much higher than that on Ni electrode. EIS results suggested that a synergetic effect on HER may exist between CeO2 particles and Ni matrix. Compared to nano-CeO2, the micro-CeO2 derived composite electrodes showed higher electrochemical activity. The possible correlation among particle size, content and catalytic activity is discussed.

Double-template fabrication of three-dimensional porous nickel electrodes for hydrogen evolution reaction

Three-dimensional (3D) porous nickel structures were fabricated via a double-template electrochemical deposition process. The construction of the foam structures was achieved by means of a hydrogen bubble dynamic template, prepared from Cu electrodeposition at high current densities. Subsequently, a Ni layer was electrodeposited on the Cu 3D template. During the nickel coating, the typical finger-like microstructure of the Cu foam becomes denser and changes to a cauliflower microstructure. The hydrogen evolution reaction (HER) on these macroporous Ni electrodes was evaluated in 30 wt.% KOH solution by means of polarization curves and electrochemical impedance spectroscopy (EIS). Results demonstrate greater apparent activity of the developed electrodes towards HER in comparison with commercial smooth Ni electrode. The 3D porous Ni electrocatalyst obtained from Cu templates synthesized at the lowest current density and the highest electrodeposition time yielded the best electrochemical activity for HER.

Electrochemical performance of porous Ni 3Al electrodes for hydrogen evolution reaction

Porous Ni 3Al intermetallic material with a mean pore diameter of around 1 μm was prepared by step sintering Ni and Al powder pressed compacts in vacuum furnace at 900 °C. The electrocatalytic activity of the as-fabricated porous Ni 3Al material as an electrode for hydrogen evolution reaction (HER) in alkaline solutions was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques. It is found that the onset potential of porous Ni 3Al for HER shifted in the positive direction favoring hydrogen generation with lower overpotential, compared with foam Ni and dense Ni electrodes. Effects of electrolyte concentration and temperature on HER as well as the electrochemical stability in alkaline solution were investigated and the electrochemical activation energy was determined for the porous Ni 3Al. The increased activity for HER was attributed to the high porosity, an increased electrochemical surface area and the nanostructure of porous Ni 3Al electrode. The corrosion tests showed that the corrosion resistance of porous Ni 3Al electrode changed during the immersion process due to the formation of passive film layers.

Effect of carbon content on Ni–Fe–C electrodes for hydrogen evolution reaction in seawater

Hydrogen evolution reaction (HER) on the Ni–Fe–C electrodes electrodeposited at current density ranging from 100 to 300 A/m 2, as well as their electrochemical properties in 3.5% NaCl solution at 90 °C and pH = 12, had been investigated by polarization measurements, EIS technique. It was shown that the carbon content and grain size of Ni–Fe–C coatings are affected by current density. In addition, the hydrogen evolution overpotential of Ni–Fe–C electrodes was related with carbon content and grain size. The Ni–Fe–C electrodes with optimum catalytic activity for the HER were found to contain the maximum carbon content 1.59% and the minimum grain size 3.4 nm. The results of a comparative analysis between carbon content and intrinsic activity are that carbon content plays an important role in intrinsic activity of Ni–Fe–C electrodes.

Fabrication of Ni nanoparticles on ordered mesoporous carbon using an immersion-electrodeposition method

Ni nanoparticles have been fabricated on the surface of CMK-3 mesoporous carbon through an immersion-electrodeposition (IE) technique. Transmission electron microscopy analysis indicated that it was a facile approach to electrochemically prepare nano-sized Ni clusters. The electrocatalytic properties of Ni/CMK-3 nanocomposites electrode for hydrogen evolution reaction have been investigated by liner scanning voltammetry in alkaline solution, and high electrocatalytic activity was observed. Therefore, for the first time, we report this IE method as a new route to prepare metal/CMK-3 nanocomposites which have potential applications in the catalytic field.

Electrodeposited Ni–S intermetallic compound film electrodes for hydrogen evolution reaction in alkaline solutions

Tailoring of nickel–sulfur (Ni–S) intermetallic compound film electrodes for hydrogen evolution reaction in alkaline solutions was attempted by electrodeposition from a typical Watts bath containing sodium thiosulfate as sulfur source and sulfosalicylic acid as additive. The XRD analysis shows that the as-deposited Ni–S film electrode with fine morphological features comprised of intermetallic compound phase structure and amorphous phase structure. The intermetallic compound film electrodes generate a higher catalytic activity for the hydrogen evolution reaction in alkaline solution in comparison with Ni–S film electrodes comprised of amorphous phase structures, even with commercial Ni mesh or Ni/RuO 2 composite electrode.

Study of molybdenum electrodes for hydrogen evolution reaction

The molybdenum electrode, Mo, has been investigated for hydrogen production via water electrolysis in 10 vol.% aqueous solutions of 1-butyl-3-methylimidazolium tetrafluoroborate (BMI·BF4) using electrochemical impedance spectroscopy (EIS). The EIS measurements show that the Mo system has much higher interfacial capacitance, and correspondently the electrical double layer formed on this electrode is thicker than those formed on nickel or platinum. The positive displacement of potential of zero charge (PZC) values indicates the specific adsorption of the imidazolium cation on the Mo surface. This study provides an elegant explanation for the better performance of Mo electrodes in the hydrogen evolution reaction (HER): the BMI cation acts as an intermediate for the proton transfer from water to the electrode surface, thereby decreasing the overpotential of HER. This model explains the synergism between Mo and the BMI cation in the HER process.

Electrochemical Preparation and Electrocatalytic Mechanisms of Ni-S Active Cathode for Hydrogen Evolution

Nickel-sulfur electrodes with different crystallographic structures were obtained by galvanostatic electrodeposition from a typical Watts bath containing sodium thiosulfate as a sulfur source. The chemical composition, crystalline structures, and surface morphologies of deposited films were determined by energy dispersion spectrum (EDS), X-ray diffraction (XRD) pattern, and scanning electron microscope (SEM) analyses. The electrocatalytic activities of the electrodes for hydrogen evolution reaction were studied in detail. The XRD result shows that the Ni-S active electrodes comprise amorphous/Ni3S2 mixed phase structures and intermetallic compound phase structures (Ni3S2) as the S content in the deposited films is increased. When the S content is 33.9% (atomic fraction) the amorphous/Ni3S2 mixed phase electrodes have a higher catalytic activity for the hydrogen evolution reaction in an alkaline solution because of the strong hydrogen adsorption ability of the Ni3S2 intermetallic compound phase. The alternating current (AC) impedance analysis results indicate that hydrogen evolution from the Ni3S2 intermetallic compound belongs to a one-step electrochemical reaction process and that for the amorphous/Ni3S2 mixed phase structures involves three steps.

Electrocatalytic activities of nanocomposite Ni 81P 16C 3 electrode for hydrogen evolution reaction in alkaline solution by electrochemical impedance spectroscopy

Kinetics of hydrogen evolution reaction (HER) was studied in 1 M NaOH at 298 K on nickel–phosphorous–carbon ( Ni 81 P 16 C 3 ) composite electrode. Evaluation of the electrode activities was carried out by steady-state polarization Tafel curves, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The kinetic parameters obtained by Tafel curves revealed that Ni–P composites modified by incorporation of carbon from L-lysine source during the electroplating process were active toward the HER. Thus, to study more precisely the electrode activities, the EIS measurements were performed. A surface roughness factor ( R f ) more than three orders of magnitude was obtained for the Ni 81 P 16 C 3 electrode. The HER rate constants were estimated using Tafel-impedance data assuming the Volmer–Heyrovský path. Analysis of the R f in conjunction with the values obtained for rate constantans showed that the increase in activity of the electrode was originated by 18% from increase in R f and by 82% from increase in the intrinsic activity (synergetic effect). Microstructure and composition of the electrodes were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), and elemental microanalysis (EDX). Besides the good electrocatalytic activity, excellent chemical and electrochemical stability was observed for Ni 81 P 16 C 3 composite electrode toward the HER.

A new method to improve surface morphology of Ni-Fe-Mo-Co alloy electrode and its catalytic activity for HER

Abstract A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction (HER). The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy electrode in 30% KOH solution containing 10% potassium sodium tartrate at 70°C for 2 h, until some of the Mo and Fe elements are leached out. The surface morphology of the Ni-Fe-Mo-Co alloy demonstrates a unique hive-like structure after the pretreatment, which has the pore size in a nanometer range (about 50 nm), a very large real surface area, and good stability. The results of the electrochemical studies show that compared to other similar electrode materials and the treated Ni-Fe-Mo-Co electrode by leaching method, the pre-treated Ni-Fe-Mo-Co electrode has a much lower overpotential and much higher exchange current density for HER. In addition, a long-term continuous electrolysis test with a current interruption shows that the Ni-Fe-Mo-Co alloy has excellent catalytic stability.

Development of nano IrO2 composite-reinforced nickel–phosphorous electrodes for hydrogen evolution reaction

Electroless and electroplated nickel electrodes are extensively used for hydrogen evolution reaction (HER). In the present work, TiO2-supported IrO2 mixed oxide composite was prepared and used to reinforce Ni–P electroless plates to be used as catalytic electrodes for HER. The electrodes exhibited high electrocatalytic activity when the electrodes were used for HER. All the parameters including particle size of the catalyst, surface roughness, and surface active sites were studied. The particle size of the IrO2 catalyst in the mixed oxide was found to have high influence on the catalytic activity of the electrodes. Low overpotential as low as 70 mV at a current density of 200 mA cm−2 was achieved with the mixed oxide-reinforced Ni–P electrodes.

Influence of Fe contamination and temperature on mechanically alloyed Co–Ni–Mo electrodes for hydrogen evolution reaction in alkaline water

Ni–Co–Mo–Fe solid solutions, such as Co 30Ni 70, Co 30Mo 70, Ni 30Mo 70, Co 10Ni 20Mo 70, Fe 10Co 25Ni 65, Fe 20Co 20Ni 60 and Fe 30Co 15Ni 55 wt.% alloys, have been produced by mechanical alloying using commercial Ni, Co, Mo and Fe powders. The electrocatalytic properties of these nanocrystalline materials have been studied for hydrogen evolution reaction (HER) in 30 wt.% KOH aqueous solution at three different temperatures (308, 323 and 343 K) to determine the effect of Fe contamination. The methods employed were cyclic voltammetry, steady-state polarization (Tafel) techniques and ac impedance. For comparison, it was found that iron improved electrocatalytic activity for the hydrogen evolution reaction. Important changes in the activity were obtained when the temperature was increased. The electrocatalytic effect of Mo became important at high overvoltages and temperatures. The MA Fe 30Co 15Ni 55 and Co 10Ni 20Mo 70 alloyed powders showed the best catalytic activities for HER.

A branched material based on biomimetic design: Synthesis and electrochemical properties

Based on the biomimetic route the metal material with tree-like fractal structure was prepared, which showed a rough surface observed by scanning electron microscopy. According to the electrochemical experiments, the formed material exhibited the strong catalytic capability as an electrode in hydrogen evolution reaction, comparing with other conventional structure materials under comparable scales. We suggested this promotion of property arose from the contribution of the great surface area and the excellent connectivity offered from the fractal structure.