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1.
The effects of iron phthalocyanine (FePc) and cobalt porphyrin (CoPp) on inner pressure and cycle behavior of sealed Ni-MH batteries were investigated in this study. The morphology of battery electrode was observed by SEM. The electrochemical impedance spectroscopy of floating-charge/discharge battery was also measured. Experimental results show that the addition of FePc or CoPp to the alloy electrode is an effective approach to decrease the internal pressure of battery during the process of charge and overcharge. In contrast to CoPp, the battery with FePc exhibits a slower capacity decay and a smaller overpotential at the same charge-discharge rate. As an electrocatalyst, FePc may more effectively speed up the reduction of oxygen, and decrease its reduction potential. As a result, the charge process is accelerated, the gas evolution is reduced and the pulverization of electrode materials is slowed down.  相似文献   

2.
A sodium modification-direct reduction coupled process was proposed for the simultaneous extraction of V and Fe from vanadium-bearing titanomagnetite. The sodium oxidation of vanadium oxides to water-soluble sodium vanadate and the transformation of iron oxides to metallic iron were accomplished in a single-step high-temperature process. The increase in roasting temperature favors the reduction of iron oxides but disfavors the oxidation of vanadium oxides. The recoveries of vanadium, iron, and titanium reached 84.52%, 89.37%, and 95.59%, respectively. Moreover, the acid decomposition efficiency of titanium slag reached 96.45%. Compared with traditional processes, the novel process provides several advantages, including a shorter flow, a lower energy consumption, and a higher utilization efficiency of vanadium-bearing titanomagnetite resources.  相似文献   

3.
A sodium modification–direct reduction coupled process was proposed for the simultaneous extraction of V and Fe from vanadium-bearing titanomagnetite.The sodium oxidation of vanadium oxides to water-soluble sodium vanadate and the transformation of iron oxides to metallic iron were accomplished in a single-step high-temperature process.The increase in roasting temperature favors the reduction of iron oxides but disfavors the oxidation of vanadium oxides.The recoveries of vanadium,iron,and titanium reached 84.52%,89.37%,and 95.59%,respectively.Moreover,the acid decomposition efficiency of titanium slag reached 96.45%.Compared with traditional processes,the novel process provides several advantages,including a shorter flow,a lower energy consumption,and a higher utilization efficiency of vanadium-bearing titanomagnetite resources.  相似文献   

4.
It is important to develop efficient technologies on removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from water due to their wide distribution and potential threat to human health. In this work, a durable and convenient electrosorption device was designed in continuous flow mode to investigate the adsorption of PFOX (X = A and S) on multiwalled carbon nanotubes (MWNTs) from water under electrochemical assistance. The electrosorption experiments were conducted under different influent and electrolyte concentrations, hydraulic retention time (HRT) and electrode distance to optimize the operation. The results showed that the highest removal efficiencies toward both PFOA and PFOS could come up to 90 % at 1 V. Compared with open circuit (OC) adsorption under the same conditions, the removal efficiencies were improved by 4.9 times (PFOA) and 4.2 times (PFOS) respectively. In addition, the MWNTs electrode was found to be reusable. These findings provide an efficient method to remove PFOX from water by electrosorption in continuous flow mode.  相似文献   

5.
Electrochemically assisted photocatalysis is an effective approach to improve photocatalytic efficiency. In this paper, modified β-PbO2 electrode was prepared by TiO2 co-deposition and characterized by SEM and XRD. Then 2.0g TiO2 modified β-PbO2 electrode (2.0 g TiO2 involved in the 200 mL co-deposition solution) was used in electrochemically assisted photocatalytic degradation of Acid Orange II and the influence of initial pH values was investigated when the potential applied across the electrodes was 1.5 V. When the potential applied was 2.5 V, the difference of the degradation process and the final products were studied. The results indicated that 2.0 g TiO2 modified β-PbO2 electrode was different from the unmodified one in that the β-PbO2 crystals became finer and the electrode became more compact and more uniform. The synergetic effect in electrochemically assisted photocatalytic degradation of Acid Orange Ⅱ was observed and degradation efficiency and TOC removal were the highest at initial solution pH 2.0. By UV-visible spectral analysis, it was proved that photoelectrochemical synergetic degradation of Acid Orange Ⅱ went through the step of producing main product maleic acid for the solution at the initial pH 2.0 within 2 h, but the degradation was slow for the solution at the initial pH 12.0.  相似文献   

6.
《矿物冶金与材料学报》2020,27(12):1687-1694
Graphite materials are widely used as electrode materials for electrochemical energy storage. N-doping is an effective method for enhancing the electrochemical properties of graphite. A novel one-step N-doping method for complete and compact carbon paper was proposed for molten salt electrolysis in the LiCl?KCl?Li3N system. The results show that the degree of graphitization of carbon paper can be improved by the electrolysis of molten salts, especially at 2.0 V. Nitrogen gas was produced at the anode and nitrogen atoms can substitute carbon atoms of carbon paper at different sites to create nitrogen doping during the electrolysis process. The doping content of N in carbon paper is up to 13.0wt%. There were three groups of nitrogen atoms, i.e. quaternary N (N-Q), pyrrolic N (N-5), and pyridinic N (N-6) in N-doping carbon paper. N-doping carbon paper as an Al-ion battery cathode shows strong charge?recharge properties.  相似文献   

7.
The electrochemical reduction process has been used to reduce spent oxide fuel to a metallic form using pyroprocessing technology for a closed fuel cycle in combination with a metal-fuel fast reactor.In the electrochemical reduction process,oxides fuels are loaded at the cathode basket in molten Li_2O–LiCl salt and electrochemically reduced to the metal form.Various approaches based on thermodynamic calculations and experimental studies have been used to understand the electrode reaction and efficiently treat spent fuels.The factors that affect the speed of the electrochemical reduction have been determined to optimize the process and scale-up the electrolysis cell.In addition,demonstrations of the integrated series of processes(electrorefining and salt distillation) with the electrochemical reduction have been conducted to realize the oxide fuel cycle.This overview provides insight into the current status of and issues related to the electrochemical processing of spent nuclear fuels.  相似文献   

8.
A solid oxide electrolysis cell (SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper, the progress on structure and operational principle of an SOEC for co-electrolyzing H2O and CO2 to generate syngas was reviewed. The recent development of high temperature H2O/CO2 co-electrolysis from solid oxide single electrolysis cell was introduced. Also investigated was H2O/CO2 co-electrolysis research using hydrogen electrode-supported nickel (Ni)-yttria-stabilized zirconia (YSZ)/YSZ/Sr-doped LaMnO3 (LSM)-YSZ cells in our group. With 50 % H2O, 15.6 % H2 and 34.4 % CO2 inlet gas to Ni- YSZ electrode, polarization curves (I- U curves) and electrochemical impedance spectra (EIS) were measured at 800 ℃ and 900 ℃. Long-term durability of electrolysis was carried out with the same inlet gas at 900 ℃ and 0.2 A/cm2. In addition, the improvement of structure and development of novel materials for increasing the electrolysis efficiency of SOECs were put forward as well.  相似文献   

9.
Due to the unique structure and special physical and chemical properties, carbon nanotubes (CNTs) have potential applications in supercapacitors. Recently, CNTs and their composites as a kind of supercapacitor electrode material have been made many achievements. In this paper, a CNTs/TiO2 composite was prepared successfully with hydrothermal method, and was used as a supercapacitor electrode material. After the tests on surface chemistry and electrochemical property, it was found that: (1) the capacitance of the CNTs/TiO2 composite electrode increased by 56%, compared with pure CNTs electrode, (2) after UV light irradiation pretreatment, due to the special photoelectric effect of TiO2 which improves the interfacial property and electrochemical property of the composite electrode, the capacitance further increased by 53% when compared with the electrode without the pretreatment, and meanwhile, the cycle life also increased significantly, i.e., the capacitance was up to 97%, after 100 cycles of charge and discharge, (3) due to the improvement of the interfacial property, the ion transport in the composite electrode became smoother, and the pore utilization was also effectively enhanced during high-current charge and discharge, and (4) due to the generation of a large amount of oxygen-containing groups on the TiO 2 surface after UV pretreatment, the CNTs/TiO2 composite electrode earned extra large pseudo capacitance, and therefore the capacitance of the composite electrode was further increased. Based on the experimental results in the present study a new process to improve surface character and electrochemicalproperty of the electrode has been developed by using a metal oxide as both pseudo capacitive material and surface modification material of the composites with a UV light irradiation.  相似文献   

10.
A gas diffusion electrode (air electrode) with a high current efficiency of electro-synthesizing H2O2 using O2 in air was prepared. The several systems with air electrode as cathode of electro-synthesizing H2O2 on the reaction spot for degrading aniline in aqueous--electro-Fenton system, photo-excitation electro-H2O2 system and photo-electro-Fenton system, were developed. The rates of decomposition of H2O2 and mineralization of aniline were experimentally measured respectively under different conditions, and the results indicated there has an excellent parallel relation between decomposition rate of H2O2 and mineralization rate of aniline. Especially, photo-electro-Fenton system, where H2O2 is decomposed the fastest, is the best system of oxidizing and degrading organic toxicants. Compared photo-electro-Fenton system with photo-Fenton system, important role is revealed in the interface of air electrode. In this paper, the mineralization mechanism of aniline in the photo-electro-Fenton system was also discussed.  相似文献   

11.
 制备了聚谷氨酸修饰碳糊电极,通过循环伏安法和交流阻抗法研究了K4Fe(CN)6/K3Fe(CN)6在修饰电极上的电化学行为,结果显示碳糊电极修饰聚谷氨酸后,K4Fe(CN)6/K3Fe(CN)6的氧化还原峰电流变大、交流阻抗变小.采用阳极溶出伏安法将所修饰碳糊电极用于铜离子的检测,在pH=4.50的醋酸-醋酸钠缓冲液中,于-0.20 V 电位下将Cu2+还原富集后再进行阳极氧化扫描,在0.14 V处获得一灵敏的铜的溶出峰,峰电流与铜浓度在1.57×10-8~1.57×10-5 mol/L的范围内呈良好的线性关系,最低检测限为5.00×10-9 mol/L.制备的聚谷氨酸修饰碳糊电极成功用于铜离子的测定.  相似文献   

12.
糖精钠和山梨酸电极产物的高效液相色谱分析   总被引:1,自引:0,他引:1  
用电化学和高效液相色谱法对糖精钠和山梨酸在-1.6V处的还原进行分离和表征,为鉴定电极反应,推断电极反应机理,提供了一种新的方法.  相似文献   

13.
 在20%的乙醇和B-R缓冲溶液(pH为7.2)中,分别比较了青蒿素(artemisinin,qhs)在金电极、银电极、铂电极、玻碳电极上的电化学行为,结果表明:在+0.00~-1.30V(vs.SCE)的电位范围内,青蒿素在金电极和铂电极上无氧化还原峰信号;而在银电极和玻碳电极上有一还原峰,无氧化峰,峰电位为分别-0.64V和-0.91V.此外在银电极和玻碳电极上,血红素(hemin)能够催化青蒿素的还原.  相似文献   

14.
银掺杂聚L-苏氨酸修饰电极的制备及对多巴胺的测定   总被引:1,自引:1,他引:0  
利用循环伏安法,研究了银和L-苏氨酸在玻碳电极表面电化学聚合的条件,制备了银掺杂聚L-苏氨酸修饰电极。并研究了多巴胺在修饰电极上的电化学行为,建立了测定多巴胺的新方法。在pH=6.5磷酸盐缓冲溶液中,扫描速率为20mV/s,多巴胺在修饰电极上产生一对明显的氧化还原峰,峰电位分别为Epa=0.218V,Epc=0.189V。用示差脉冲伏安法测定时,峰电流与多巴胺浓度分别在8.00×10-7~1.00×10-5和1.00×10-5~1.00×10-4mol/L范围内呈良好的线性关系,检出限为1.0×10-7mol/L。用于药物中多巴胺的测定,结果满意。  相似文献   

15.
有机体系下,采用循环伏安法(CV)在活性炭电极表面电聚合聚苯胺制备聚苯胺/活性炭复合电极,通过循环伏安、恒流充放电和电化学交流阻抗谱(EIS)测试了电极的电化学特性,结果表明,聚苯胺/活性炭复合电极具有良好的电容行为,在-1.0~1.5V参比极为Ag/AgCl,测试区间内具有较大的电化学容量,电极比电容高达276F·g-1,较活性炭电极的比电容92F·g-1有了很大提高.并且交流阻抗法测得活性炭电极的电荷转移电阻Rct为4.9Ω,而复合电极Rct仅2.4Ω.1000次充放电测试后,复合电极比电容仅衰减15.7%.由此表明,在有机体系下聚苯胺/活性炭复合电极是一种具有良好循环寿命和高比电容的复合电极材料.  相似文献   

16.
近年来,CO_2的光电化学还原引起人们极大的兴趣,已有利用SiC粉末进行CO_2光催化还原的报道。本研究首次利用p-SiC膜光阴极还原CO_2,得到较高的CH_3OH产率。1 实验 在导电玻璃上采用水银光敏化CVD法制得微晶p-SiC膜,电极表面用4.6%HF溶液抛  相似文献   

17.
提出了由两束碳纤维和Ag/AgCl丝制备组合电极的方法和处理方法,系统地讨论了电化学条件对组合电极响应的影响,利用该组合电极,测定国家标准物质锌(CRMGBW02703)中微量钢,相对标准偏差2.0%.相对误差0.5%,结果令人满意.  相似文献   

18.
以L-半胱氨酸作为电极修饰剂,采用循环伏安法研究L-Cys/GC电极的制备和DA在该修饰电极的电化学行为及其测定.DA在pH=6.684的磷酸盐缓冲溶液中,在L-Cys/GC电极上产生一对灵敏的氧化还原峰,峰电位分别为Epa=0.180 V和Epc=0.125 V(vs.SCE).同时用伏安法测定DA的线性范围为1×1...  相似文献   

19.
以L-半胱氨酸作为电极修饰剂,采用循环伏安法研究L-Cys/GC电极的制备和DA在该修饰电极的电化学行为及其测定.DA在pH=6.684的磷酸盐缓冲溶液中,在L-Cys/GC电极上产生一对灵敏的氧化还原峰,峰电位分别为Epa=0.180 V和Epc=0.125 V(vs.SCE).同时用伏安法测定DA的线性范围为1×10-3~1.0×10-6 mol/L,检出限可低达1.0×10-7mol/L(S/N=3).对1×10-4 mol/L DA平行测定50次,其相对标准偏差约为2.5%.该电极可望进一步发展为微电极,用于生物活体内的神经递质DA的实际检测.  相似文献   

20.
方波溶出伏安法快速测定染发剂中对苯二胺   总被引:1,自引:0,他引:1  
采用循环伏安法研究了对苯二胺在铂电极上的电化学行为。实验发现,在0.1 mol/LpH=6.0的磷酸盐缓冲溶液中,对苯二胺能在铂盘电极上产生良好的氧化还原峰,对苯二胺氧化还原峰峰电位分别为+0.25 V和+0.19 V(vs.Ag/AgC l,饱和KC l溶液)。考察了扫描速度和pH对峰电位和峰电流的影响,结果表明对苯二胺在铂盘电极上的电极反应属于等电子等质子反应,反应过程受吸附控制。基于此建立了方波溶出伏安法快速测定染发剂中对苯二胺的分析方法。该方法具有分析时间短、操作简单等优点。该方法的线性范围为3.24-108.14 mg/L,R=0.9990,检出限为1.1mg/L,浓度为43.2 mg/L时相对标准偏差(n=11)为1.57%,对4种市售染发剂中对苯二胺含量进行了测定,结果满意。  相似文献   

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