Papers by Keyword: Electrochemical (EC)

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Authors: Qi Zhou Dai, Fei Liao, Shao Qing Cai, Jia De Wang, Jian Meng Chen
Abstract: Organic wastewater pollution control was one of the focus researches for environmental workers. In this study, high active electrode was made and hydrogen peroxide production via cathodic reduction of oxygen was studied, the H2O2 generated in the optimization of research and the effect of dye wastewater degradation under the typical conditions were explored. The effects of mass ratio between graphite and PTFE, Na2SO4 concentration, cathodic potential, pH and gas flow rate on hydrogen peroxide output were investigated. The optimized operational parameters were as follows: graphite and PTFE 5:1, pH=6, Na2SO4 concentration 0.5 mol/L, oxygen flow rate 450mL/min, and cathodic potential -1.2 V (vs SCE). Hydrogen peroxide concentration could reach 66.17 mg/L after 2h at optimized condition. Meanwhile, dye removal could reach about 70% at the same time. Therefore, the use of active electrode as cathode has shown promising prospect in dye wastewater treatment.
Authors: Zhen Jing Zhuang
Abstract: Pd nanoparticles have been prepared on the surface of glassy carbon electrode (GCE) by electrochemical deposition method and applied for the nonenzymatic detection of H2O2. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to investigate the as-prepared Pd nanoparticles on the surface of GCE. The electrochemical properties of Pd nanoparticles modified GCE were also characterized by cyclic voltammetry and chronoamperometry. The results showed that Pd nanoparticles modified GCE had a favorable catalytic ability for the reduction of H2O2 in PBS medium (pH=7.6). At an applied potential of -0.06 V, the nonenzymatic H2O2 sensors produce high and reproducible sensitivity to H2O2 with 52.45 μA/mmol۰dm–3. Linear responses were obtained over a concentration range from 0.15 mmol۰dm–3 to 18 mmol۰dm–3 with a detection limit of 25 μmol۰dm–3 (S/N=3). Additionally, it exhibited a rapid response time (within 1s), which was much faster than some nonenzymatic H2O2 sensors.
Authors: Sung Hyun Kim, Sang Gyun Lee, Seung Geon Choi, Eun Sang Lee, Seung Bok Choi, Chul Hee Lee
Abstract: Electropolishing, the anodic dissolution process without contact with tools, is a surface Treatment method to make a surface planarization using an electrochemical reaction with low current density. Stainless steel can be put various applications which require purity and high precision surface of products. The aim of this study is to investigate the characteristic of electropolishing effect for stainless steel workpieces. In order to analyze the characteristics of electropolishing effect, surface roughness and micro-burr size were measured in terms of machining conditions such as current density, machining time and electrode gap. The tendencies about improvement of surface roughness by electropolishing for stainless steel workpieces were determined.
Authors: Seiji Ban, Norihiro Arimoto, A. Harada, J. Hasegawa, S. Maruno
Authors: Yu Ye Xu, Bi Lan Lin
Abstract: HRB400 reinforcing steel due to high strength and high ductibility is as the main reinforcing steel in “Code for design of concrete structures (GB50010-2002)” in China. Cyclic potentiodynamic polarization technique was used to investigate the electrochemical corrosion bebavior of HRB400 reinforcing steel in Simulated Concrete Pore solutions (SCP solutions) differently contaminated by bicarbonate ions and/or chloride ions. The evolution feature of the corrosion parameters was analyzed and was compared with that of HPB235 reinforcing steel. The results show that the corrosion characteristics of HRB400 and HPB235 were exceedingly similar before the destruction of the passivation film. However, HRB400 is remarkedly more susceptible to chloride ions and carbonation than HPB235 during the failure of the passivation films. The pH threshold for HRB400 is larger than that for HPB235, and the chlorides threshold for the former is smaller than that of the latter. When HRB400 and HPB235 were connected and exposed to an aggressive environment, the galvanic corrosion will occur where HRB400 is anode and HPB235 is cathode. To ensure the durability of the reinforcing concrete structures, it is necessary to make the connection points insulate.
Authors: Lu Lu Zhang, Da Fu Cui, Xing Chen, Hao Yuan Cai, Hui Li, Jian Hai Sun
Abstract: The construction and performance of a novel electrochemical (EC) surface plasmon resonance (SPR) instrument based on a mini three electrode flow cell that was designed and manufactured by MEMS technology is described. The working electrode is 50nm gold and counter and reference electrodes, made of Au and Ag/AgCl separately, are 0.6 mm in diameter. The flow channel is made of polydimethylsiloxane (PDMS) with 1mm in width, 200μm in depth, 5μL in volume. The process for activating and modifying the working electrode is given by the real-time SPR detection. The Cyclic voltammetry (CV) and SPR detection are conducted simultaneously in potassium ferricyanide solution system. It is proved that the signal of redox reaction and the change of refractive index have a well correlation by the potential sweep experiment. Four kinds of concentration of potassium ferricyanide are analyzed and the peak oxidizing current, obtained from the curve, is proportional to the respective concentration of the sample. The EC-SPR experiment is also carried out in CuSO4 system and the results is similar to potassium ferricyanide.
Authors: Jing Wang, Dao Bin Mu, Feng Wu, Shi Chen
Abstract: La1-xMgxNi2.8Co0.7 (x=0.1, 0.3, 0.5) hydrogen storage alloy was synthesized by solid diffusion method. The microstructure of the alloy was analyzed by XRD when the content of Mg was changed. When x equaled to 0.3, there was relative much La2Ni7 phase in the alloy and the alloy exhibited better integrated electrochemical performance. Its maximum discharge capacity reached 355.4mAh/g and capacity retention after 50 cycles(S50)was 77.80%. The results showed the existence of La2Ni7 phase would be conductive to the integrated electrochemical performance of the alloy.
Authors: Chuan He, Xu Chen, Yang Xu, Zhi Yong Liu
Abstract: X80 pipeline steel specimens were treated by electrochemical hydrogen charging under various current density and charging time. The polarization resistance and corrosion rate of X80 steel were analyzed in Yingtan simulated soil solution under the different hydrogen charging conditions. The results showed that hydrogen accelerated anodic dissolution and enhanced corrosion sensitivity. With hydrogen in the steel, the charge transfer resistance and polarization resistance decreased, double electric layer capacitor and corrosion current increased. The effects were enhanced with the increase of hydrogen charging time and current density.
Authors: Chang Yeoul Kim, Seong Geun Cho, Seok Park, Tae Yeoung Lim, Duck Kyun Choi
Abstract: Electrochromic WO3 thin film was prepared by using tungsten metal solution in hydrogen peroxide as a starting solution and by a sol-gel dip coating method. The thermal analysis was conducted by DSC/TG method. A DSC/TG analysis and the XRD patterns showed that a tungsten oxide crystal phase was formed at 400oC. WO3 thin film when heat-treated at 300oC was amorphous and had a better electrochemical property than that of the crystalline phase. Crystallization of tungsten oxide decreased active sites of ion intercalation so that the current density decreased with heat-treatment temperature.
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