Electrochemical Degradation of Indigocarmine Dye at Ni/Graphite Modified Electrode in Aqueous Solution

Nickel Graphite modified electrode (Ni/GME) was prepared by electrochemical method and degradation of Indigocarmine (IC) dye was carried out. An investigation between the efficiency of degradation by graphite electrode and the Ni/graphite modified electrode has been carried out. The different effects of concentration, current density and temperature on the rate of degradation were studied. This study shows that the rate of the degradation is more for Ni doped modified graphite electrode. UV-Visible spectra before and after degradation of the dye solution were observed. The thin film formation of Ni or encapsulated in graphite rod is observed by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM & EDAX). The instantaneous current effectiveness values of different experimental conditions are evaluated. The anodic oxidation by Ni/ graphite modified electrode showed the complete degradation of aqueous solution indigocarmine, which is confirmed by UV-Visible and chemical oxygen demand (COD) measurements. The dye is converted into CO2, H2O and simpler inorganic salts. The results observed for reuse of modified electrodes indicate that the Ni/graphite modified electrode would be a promising anode for electrochemical degradation of indigocarmine. This method can be applied for the remediation of waste water containing organics, cost-effective and simple.

Electrocatalytic Activity of Ni/C Electrodes Prepared by Metal Vapor Synthesis For Hydrogen Evolution in Alkaline Solution

The metal vapor synthesis (MVS) methed was used to prepare activatedcarbon supported nickel electrode. The electrocatalytic activity of the electrode forhydrogen evolution reaction(HGR) in alkaline solution was studied. Cathodicpolarization curves showed the electrocatalytic activity of Ni/C electrode prepared byMVS method was higher than that of the one prepared by conventional method.

Electrode Process of Y^(3+)Ion on Molybdenum and Nickel Electrodes in YCl_3-NaCl-KCl Melt

The electrode process of Y^(3+)ion on molybdenum and nickel electrodes has been studied by cyclic voltammetry and chronopotentiometry in the YCl_3-NaCl-KCl melt.The overall charge transfer process is a two-step reaction:Y^(3+)+e=Y^(2+);Y^(2+)+2e=Y.Yttrium reduced on the nickel electrode can form a series of Ni-Y alloys.X-ray diffraction analysis was employed to determine the alloy compositions formed under different con- ditions.

Preliminary study on electrochemical reduction of carbon dioxide on nickel and platinum electrodes

The electrochemical reduction of carbon dioxide was investigated on nickel and platinum electrodes in 0.5 mol dm^-3 KHCO3 solutions. The main products were formic acid and carbon monoxide during the electroreduction of CO2, and the Faradaic efficiency for this process depended on the characteristics of the electrode. At ambient temperature and pressure, the Faradaic efficiency was measured to be 8.6% and 2.5 % respectively for the production of formic acid and CO with Pt electrode at - 1.3V vs Ag/AgCl （saturated KCl）. At this same potential, the Faradaic efficiency was measured to be 8.9% and 1.7% respectively with Ni electrode. Tafel plots showed that the electrochemical reduction of CO2 was not limited by the mass transfer process in the range of -0.8 to - 1.2V vs Ag/AgCl （saturated KCl）.

Highly efficient FexNi1-xOy/CP electrode prepared via simple soaking and heating treatments for electrocatalytic water oxidation

The oxygen evolution reaction（OER） is a key step in the overall water splitting process. Numerous electrocatalysts have been developed to lower the overpotential and accelerate the kinetics of the OER. In this work, a simple soaking and heating treatment was used to form a stable and efficient FeNiO/CP electrode. The electrode combined nickel and iron oxides on a commercial carbon paper were used for electrocatalytic water oxidation. The best FeNiO/CP electrode（Ni/Fe = 15/1） displayed a current density of 10 mA/cmat a low overpotential of 290 mV in 0.1 M KOH solution with a Tafel slope of 52 mV/dec.A higher current density of0 mA/cmat the same overpotential and a lower Tafel slope of 43 mV/dec was obtained for this electrode in 1.0 M KOH solution. Excellent durability of the FeNiO/CP electrode in 1.0 M KOH solution was confirmed under a high current density of 136 mA/cmat an overpotential of 340 mV.

Microstructure and electrochemical characteristics of nonstoichiometric La-rich AB_5-type alloy for Ni/MH battery electrode

The nonstoichiometric La-rich mischmetal (designated by MI)-based hydrogen storage alloy with a composition of MI(Ni0.64Co0.2Mn0.12Al0.04)(4.76) was prepared by arc melting and annealed at 1173 K for 10 h to investigate the effect of annealing treatment on the microstructure and electrochemical characteristics of the alloy. X-ray diffraction analysis showed that annealing can cause a release of the crystal lattice strain and an increase in amounts of the La2Ni7-type second phase in MI(Ni0.64Co0.20Mn0.12Al0.04)(4.76) alloy. Scanning electron microscopy and electron probe microanalysis examinations indicated that annealing leads to disappearance of the dendrite structure in the as-cast alloy, growth of crystal grain, and decrease of composition segregation. The annealing at 1173 K for 10 h flattened and extended the potential plateau and increased the maximum discharge capacity to 328 mA center dot h/g from 310 mA center dot h/g and the cycling life. The mechanism of the improvement in electrochemical characteristics was discussed based on the alloy microstructure change induced by annealing.

Unveiling the role of Ni in Ru-Ni oxide for oxygen evolution: Lattice oxygen participation enhanced by structural distortion

Introducing Ni in Ru oxide is a promising approach to enhance the catalytic activity for the oxygen evolution reaction(OER).However,the role of Ni(which has a poor intrinsic activity)is not fully understood.Here,a Ru NiO_(x)electrode fabricated via a modified dip coating method exhibited excellent OER performance in acidic media,and neutral media for CO_(2)reduction reaction.We combined in-situ/operando X-ray absorption near-edge structure and on-line inductively coupled plasma mass spectrometry studies to unveil the role of the Ni introduced in the Ru oxide.We propose that the Ni not only transforms the electronic structure of the Ru oxide,but also produces a large number of oxygen vacancies by distorting the oxygen lattice structure at low overpotentials,increasing the participation of lattice oxygen for OER.This work demonstrates the real behavior of bimetallic oxide materials under applied potentials and provides new insights into the development of efficient electrocatalysts.

High-performance (K,Na)NbO_(3)-based multilayer piezoelectric ceramic actuators with nickel inner electrodes

Multilayer ceramic actuator(MLCA)has been widely employed in actuators due to the large cumulative displacement under the low driving voltage.In this work,the MLCA devices consisting of a lead-free MnCO_(3-)and CuO-doped 0.96(K_(0.48)Na_(0.52))(Nb_(0.96)Ta_(0.04))O_(3)-0.04CaZrO_(3) piezoelectric ceramics and a base nickel(Ni)metal inner electrode were well co-fired by the two-step sintering process in a reducing atmosphere.The ceramic layer/electrode interface is well-integrated and clearly continuous without distinct interdiffusion and chemical reaction,which is beneficial to the electrical reliability of the MLCA.As a result,the MLCA laminated with nine active ceramic layers obtains an ultrahigh piezoelectric coefficient d_(33) of 3157 pC/N,about 9 times than bulk ceramics.The 0.5 mm-thick MLCA composed of a series of~50μm-thick ceramic layers and~3μm-thick Ni electrodes reaches a high 1.8μm displacement under the low applied voltage of 200 V(the same displacement requires a voltage as high as 3700 V for~1 mm-thick bulk ceramics).The excellent electrical performance and low-cost base electrode reveal that the(K,Na)NbO_(3)(KNN)-based MLCAs are promising lead-free candidate for actuator application.

Electrochemical Behaviour of Magnesium（Ⅱ） on Ni Electrode in LiCl-KCl Eutectic

The electrochemical behaviour of magnesium（Ⅱ） and the formation mechanism of Mg-Ni alloys on Ni electrode were studied in LiCl-KCl eutectic using various electrochemical techniques. Cyclic voltammogram and square-wave voltammogram revealed that under-potential deposition of magnesium occurred on Ni electrode because Mg-Ni alloy compounds were formed. The thermodynamic properties of the Mg-Ni intermetaUics, Mg2Ni and MgNi2, were determined using open circuit chronopotentiometry in the temperature range of 8186893 K. Moreover, the Mg-Ni alloys were produced by potentiostatic and galvanostatic electrolysis under different conditions and characterized by means of scanning electron microscopy（SEM） equipped with energy dispersive spectrometry（EDS） and X-ray diffraction（XRD）. The experimental results indicate that Mg-Ni intermetaUic compounds can be selectively produced by potentiostatic electrolysis.

Electrochemical behavior of Y(Ⅲ) and preparation of Y-Ni intermetallic compounds in molten LiCl-KCl salts

The work concerned the electrochemical behaviors of Y（Ⅲ） on W and Ni electrodes in molten LiCl-KCl salts by a series of electrochemical techniques. The electrochemical reaction of Y（Ⅲ） to Y（0） proceeded in a one-step reduction process with the exchange of three electrons, Y（Ⅲ）＋3e^–→Y（0）. Compared with the cyclic voltammogram and square wave voltammogram obtained on W electrode, the reduction potential of Y（Ⅲ） on Ni electrode was observed at less negative potential than the one of Y（Ⅲ） to give pure Y metal on W electrode, which revealed the occurrence of underpotential deposition of Y（Ⅲ） on Ni electrode. Electromotive force（emf） measurements were performed to calculate the relative partial molar Gibbs energies and activities of Y in Y-Ni alloys. The standard Gibbs energies of formation for different Y-Ni intermetallic compounds were also estimated. The different Y-Ni alloys were formed by potentiostatic electrolysis at different potentials and characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and energy dispersive spectrometry（EDS）. It was found that four intermetallic compounds, YNi5, Y2Ni7, YNi3 and YNi2, were selectively produced by controlling applied potential.

A promising energy storage system:rechargeable Ni-Zn battery

The sharp depletion of fossil fuel resources and its associated increasingly deteriorated environmental pollution are vital challenging energy issues, which are one of the most crucial research hot spots in the twenty-first century.Rechargeable Ni–Zn batteries（RNZBs）, delivering high power density in aqueous electrolytes with stable cycle performance, are expected to be promising candidates to alleviate the current energy and environmental problems,and play an important role in green power sources. Many efforts have been focused on the investigations and improvements of RNZBs in recent decades, and it is necessary to summarize and review the achievements and challenges in this advancing field. In this paper, we review various batteries, compare and highlight the advantages of RNZBs, and introduce the recent advances in the development of electrode materials and electrolytes of RNZBs,especially the applications of novel nanostructured materials for the active electrodes. Some prospective investigation trends of RNZBs are also proposed and discussed.

Resistive switching characteristics of Ni/HfO_2/Pt ReRAM

This study investigated the resistive switching characteristics of the Ni/HfCVPt structure for nonvolatile memory application.The Ni/HfO_2/Pt device showed bipolar resistive switching（RS） without a forming process, and the formation and rupture of conducting filaments are responsible for the resistive switching phenomenon.In addition,the device showed some excellent memory performances,including a large on/off ratio（〉 3×10~5）,very good data retention（〉 10~3 s @ 200℃） and uniformity of switching parameters.Considering these results,the Ni/HfO_2/Pt device has the potential for nonvolatile memory applications.