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金属阳极涂层的析氧电位 总被引:1,自引:0,他引:1
以金属阳极涂层的析氯电位检测方法为基础,在进行部分改变后,对金属阳极的析氧电位进行检测。在十几个金属阳极生产(修复)单位,实际生产的金属阳极产品抽取的试样中,以对几十个试片的析氧电位检测结果为依据,进行分析讨论,给出了不同涂层的析氧极化情况,析氧电位和的氧析氯电位差的统计情况。同时证明,甘汞电极也可以做为金属阳极涂层析氧电位检测的参比电极。 相似文献
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近年来基于阳极析氧催化的电解水制氢技术引起了广泛关注,安全、高效的阳极析氧催化剂是实现该技术的核心。银基析氧催化剂具有操作条件温和、析氧过电位低及结构易于调变的特性,是一种颇具发展前景的新型阳极析氧催化剂。本文综述了Ag基析氧催化剂的制备及其在电解水制氢方面的应用,着重介绍了Ag基析氧催化剂的两种调控改性方法,包括原位调控方法和后制备调控方法,其中原位调控方法主要有电解质溶液的匹配、电解质(浓度、酸碱度、温度)的调变和工作电极的修饰,后制备调控方法主要有金属氧化物复合、石墨烯复合和银氧化物纳米晶的调控。将原位调控和后制备调控相结合,可为制备具有较低过电势、较高催化活性的新型Ag基阳极析氧催化剂提供方法指导和为后续研究提供依据。 相似文献
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寻找一种高效、稳定和低成本的析氧阳极材料对于在碱性环境中电解水的研究具有非常重要的实际意义。近年来,Ni-Fe基材料以其低成本及在碱性条件下具有高催化活性的特点成为析氧反应电极材料的研究热点。本文概述了近几年国内外学者对不同的Ni-Fe基析氧材料(包括Ni-Fe合金、Ni-Fe氧化物、Ni-Fe层状双金属氢氧化物及Ni-Fe基复合材料等)在合成方法、物理形态、化学结构和催化性能等方面所进行的研究,介绍了Ni-Fe基材料的析氧反应机理的进展,探究了析氧反应活性相以及Fe的掺入对Ni基氢氧化物的结构和活性的影响,最后指出了合成方法的改进及详细反应机理的探究将会成为未来Ni-Fe基析氧阳极材料的重点研究方向。 相似文献
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金属阳极表面活性及电化学特性评价 总被引:1,自引:0,他引:1
丁泽华 《化学工业与工程技术》2004,25(6):38-40
通过对电极析氯电位和析氧电位测定及电极极化曲线、电极强化寿命测试,评价金属阳极表面活性及电化学特性,指导金属阳极电解槽管理。 相似文献
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A model has been developed to illustrate the complex interplay between the acidifying electrode reactions for oxygen evolution, mass transport and homogeneous reactions in pH-neutral electrolytes. Modelled polarisation curves of the oxygen evolution reaction were verified by polarisation curves experimentally measured in 5 M NaClO4 on a RDE of DSA material. The conditions in the simulations and in the experiments were similar to those in the chlorate process (high ionic strength, 70 °C, chromate-containing electrolyte, DSA electrode), in which the oxygen evolution reaction is one of the possible side reactions. The model predicted the concentration gradients of H+, OH−, CrO42− and HCrO4− during oxygen evolution on the RDE. It was found that an important part of the chromate buffering effect at high current densities occurs in a thin (in the order of nanometers) reaction layer at the anode. From comparisons between the model and experiments, a buffering reaction has been proposed. The most likely reaction for the chromate buffering in the investigated system is CrO42− reacting with water to HCrO4− and OH−. In the chlorate process, where chromate is a buffer and oxygen evolution is a side reaction, it is likely that chromate promotes oxygen evolution from OH−. 相似文献
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The oxidation of sulphite ion to sulphate ion appears to offer attractions as an anodic reaction for cells operated at high current density such as those used in the fluidized bed electrodeposition of metals. In the present investigation several anodes were tried in a cell where the anolyte was aqueous ammonium sulphite solution and copper was electrowon from acidified aqueous cupric sulphate solution onto a fluidized cathode. The cell voltage was determined as a function of current density and a porous anode consisting of reticulated vitreous carbon with a lead coating was found to yield low cell voltages as did a DSA anode. The former anode did not evolve oxygen in the current density range up to 5500 A m–2 whereas the latter showed the onset of oxygen evolution as the current density was raised. Some effects of anolyte flow rate and extent of conversion of sulphite to sulphate, as well as the distribution of potential drops in the cell were determined. Below 3500 Am–2, sulphite ion oxidation using the reticulated vitreous carbon anode resulted in cell voltages below those of conventional commercial cells for copper electrowinning. 相似文献
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T. Subbaiah P. Singh G. Hefter D. Muir R.P. Das 《Journal of Applied Electrochemistry》2000,30(2):181-186
The growing interest in the electrowinning of copper has lead to several modifications including anodic reactions proposed to reduce the high energy requirement. The addition of sulphurous acid to a copper sulphate electrolyte has been studied to avoid oxygen evolution at the anode which requires a potential in excess of 2V. In particular, the effect of different anode materials, concentration of sulphurous acid, current density, copper and sulphuric acid concentrations in the electrolyte have been investigated. Measurements of anode potential, cell voltage, current efficiency and energy consumption during the electrowinning of copper have been made using a diaphragm cell. It was found that graphite and lead coated with Ir–O2 are better electrode materials than lead and DSA anodes and sulphurous acid can be used as anodic depolarizer. 相似文献
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Jari Aromaa 《Electrochimica acta》2006,51(27):6104-6110
Most of the hydrometallurgical processes use sulphuric acid solutions. The main anodic reaction is oxygen evolution by decomposition of water. Traditional anode materials have been lead alloys that have high overpotential towards oxygen evolution. Oxide type anodes are more active but they are also more expensive. In this work, the activities of binary RuO2-TiO2 anodes were measured using different electrochemical techniques. The activity measurements were based on the measurement of the redox reaction between Ru(III) and Ru(IV) in cyclic voltammetry and on the oxygen evolution reaction in potentiostatic tests and galvanostatic electrochemical impedance spectroscopy. Factors related to intrinsic electrocatalytic properties and electrochemically active surface area could be separated. Above 30 mol% no significant increase in activity towards oxygen evolution is gained by increasing the concentration of active oxide. With low amount of active oxide most of the active sites are inside the pores and cracks. This will cause anode failure by bubble formation inside the anode. 相似文献
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The problem at hand is the electrochemical oxidation of oxalate ion, which is accelerated by fluoride ion at a platinum anode. The hypothesis that fluoride ion traps incipient hydroxyl radicals as hydroxyfluoride radical anions was not supported by ESR experiments in which hydroxyl radicals were generated in the presence of the spin trap α-(4-pyridyl-1-oxide) N-tert-butyl-nitrone with and without the addition of fluoride ion. The electrochemical oxidation of oxalate at constant current followed current controlled kinetics both at a platinum anode, as observed previously, and at a boron-doped diamond anode, but the rate of the latter reaction was indifferent to the presence of fluoride ion. We propose that the competition of fluoride and hydroxide ions for the Pt/PtOn surface inhibits the dimerization reactions that lead to oxygen evolution; the displacement of oxygen evolution to more positive potentials overcomes the overpotential for the oxidation of oxalate at this anode. Fluoride ion has no influence on the oxidation of oxalate at BDD because oxygen evolution inherently occurs at more positive potentials at this anode. 相似文献