Electrochemical discharges—Discovery and early applications

Electrochemical discharge phenomenon, as well known as plasma electrolysis, electrode effects or contact glow discharge electrolysis, was first described in literature more than 150 years ago. Today this effect is studied only in quite specialised applications. This was not always the case. During the 19th century and early 20th century, electrochemical discharges were intensively studied and a broad spectrum of applications, ranging from X-ray imaging to wireless telegraphy, was developed. This communication retraces this early history of electrochemical discharges by highlighting the interesting electrochemical effects and applications linked to them. The paper ends by shortly mentioning today's applications of electrochemical discharges which are in the field of micro-machining, surface engineering, nanotechnology and waste water treatment.     

Bacterial exopolysaccharides for corrosion resistance on low carbon steel

Corrosion is a global issue that affects safety and economics. There is an increasing demand for bio‐based polymers for industrial applications and production of polymers by micro‐organisms is especially attractive. This work reports on the electrochemical and physical properties of exopolysaccharides produced from lactic acid bacteria and their suitability as anti‐corrosive coatings. Bacterial exopolysaccharide coatings protected low carbon steel from corrosion by reducing ionic diffusion rates and maintaining a relatively passive metal‐coating interface. The data suggest the kinetics of film deposition are fast (<5 min) and there is little excess (loosely bound) material when hydrated. Measurements show thin (50 nm) coatings that when exposed to water exhibit self‐repairing phenomenon. The corrosion protection offered by the coatings is reported as the corrosion rate calculated from the corrosion current obtained by electrochemical impedance and polarization spectroscopy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45032.     

Milestones and perspectives in electrochemically promoted catalysis

Electrochemical promotion of catalysis is a unique tool for the in situ tuning of catalytic activity of electronically conductive metals or metal oxides in contact with solid electrolytes. The importance of electrochemical promotion to heterogeneous catalysis, surface science and electrochemistry research for the investigation of spillover phenomena and metal–support interactions is well recognized. The unlimited applications of the phenomenon, in terms of catalysts, solid electrolytes or catalytic reactions selection, has been proven through numerous laboratory investigations. Though the molecular origin of electrochemical promotion has been revealed, using a variety of experimental techniques and theoretical calculations, there is still a shortage on the practical level. However, in the last decade, spectacular progress has been made in the development of effective, low cost electropromoted catalysts and reactors. The major technological advances and milestones towards the practical utilization of electrochemical promotion are surveyed in view of electrocatalysts development and system/reactor engineering.     

碳纳米管阵列在电化学中的应用

高定向的碳纳米管阵列由于有优越的电导率、高比表面积、发达的多孔结构而具有良好的电化学性能如大容量、优异的速率性能和较长的循环寿命,这些独特的性质使其在电化学领域显现出巨大的应用潜力。本文简要介绍了碳纳米管阵列的制备,并从电化学储能、电化学催化和电化学传感器等领域综述近年来碳纳米管阵列在电化学应用中的最新研究进展,分析了其所面临的问题,并提出了未来碳纳米管阵列在电化学应用中的发展方向。关键词：碳纳米管阵列；电化学性能；储能；催化；传感器中图分类号：     

Blue Fluorescence and Bipolar Transport Materials Based on Anthracene and Their Application in OLEDs

The phenomenon of organic electroluminescence (EL) was first discovered from studies on anthracene crystals in the 1960s. Since then, its derivatives have been studied extensively in applications such as organic light-emitting diodes (OLEDs) and organic thin-film transistors because of their excellent EL, transport, and good electrochemical properties. A blue fluorescence emitter based on anthracene is also important in constructing hybrid tandem white OLEDs for lighting applications. This article provides a review about the development of blue host OLED materials based on molecules designed and derived from the core structure of anthracene and their application as bipolar charge-carrier transport materials in OLEDs. The recent development of efficient, stable, blue-doped p-i-n OLEDs with simplified device architecture based on the single common host 2-methyl-9,10-di(2-napthyl)anthracene, with its stable thin-film morphology, large band gap energy, high fluorescence quantum yield, and ambipolar charge-carrier transport properties, is also highlighted.     

Photoinduced layer phenomenon caused by iodine formation in MoSe2: electrolyte (iodide) junctions

When iodide is photooxidized at a n-type MoSe₂ electrode at a high rate, a dim film is observed to spread over the metallic bright electrode and the reflected light intensity throughout the visible and near ir spectral region drops by 70–80%. The phenomenon can — in a reversible way — be controlled by small potential variations (0 ? +0.5 V) and beyond +1.0 V produces electrochemical oscillations, which are paralleled by an additional reflection change which can be seen to propagate across the electrode surface.The phenomenon could be reproduced in absence of light at semiconducting p-type MoSe₂, at metallic NbSe₂ and at Pt-electrodes which excluded the possibility that the pronounced optical changes are produced by a photoelectrochemical or electrochemical modification of layer-type electrode material in presence of iodide. The reflection anomalies can be explained by physical properties of an iodine layer, which is formed in the iodide-depleted diffusion region at the electrode surface.Evidence is given that the spreading of the dim film is actually a phase transition from dispersed to crystalline iodine with an asymmetrical size distribution within the I^? depleted diffusion layer. The resulting gradient of the refraction index works like an anti-reflecting coating. The described phenomenon will have to be considered in attempts to optimize solar cells based on the I^?/I₂ redox couple and it might be of some practical interest for antireflecting layer-technology and electro-optical applications.     

Charge density in non‐isotropic electrolytes conducting current

This article presents applications of an electrochemical model that can predict concentrations and electric current distributions assuming neither electroneutrality nor negligible concentration gradients. This numerical model is used to analyse two cases: a liquid‐junction and a lithium‐ion cell. For both cases, it is shown how the inclusion of charge density effects on the electric field is beneficial. For the case of a liquid‐junction the predicted potential gradient is compared with values experimentally and numerically determined by other researchers. For the case of a charging lithium‐ion cell, a phenomenon seen experimentally (but not previously reported by other models) is predicted. © 2011 Canadian Society for Chemical Engineering     

Highlights in Coupled Electrochemical Flow Cell-Mass Spectrometry,EC/MS

Probing electrochemical processes by mass spectrometry (EC/MS) is a developing field that benefits from the unmatched identification power of mass spectrometry and from the rapid transfer of electrochemical cell products to the mass spectrometer. Most of the current EC/MS efforts are directed towards the development of differential electrochemical mass spectrometry (DEMS) using the electro-ionization source for identification of volatile compounds, and towards the application of electrospray mass spectrometers for determination of semivolatile and nonvolatile products. The challenges in coupling mass spectrometry and electrochemistry are described, and different approaches to using the coupled system for diverse applications are reviewed, with emphasis on electrospray mass spectrometry. Reaction mechanism studies, diagnostic applications, and activity imaging of electrodes are demonstrated based on approaches that were devised in our laboratory.     

In situ neutron radiography analysis of graphite/NCA lithium-ion battery during overcharge

Overcharge of lithium-ion batteries can lead to the deposition of lithium ions on the surface of graphite electrodes. The phenomenon of lithium deposition causes reduced electrochemical performance and presents safety concerns for lithium-ion batteries in high-power applications. This study presents a technique using neutron radiography (NR) for in situ visualization of the effects of overcharge in a graphite/NCA (LiNi_0.8Co_0.15Al_0.05O₂) lithium-ion cell. Patterns of deposition of solid material on the surface of the graphite electrode observed in the radiographs were confirmed by direct observation of the electrode. Inductively coupled plasma mass spectrometry was used to verify the elemental contents of the deposited material. NR is shown to be a promising tool for the study of lithium-ion batteries in high-power applications.     

Electrochemical photovoltaic cells—review of recent developments

Photoelectrochemistry is attracting extensive attention from scientists worldwide for its use in converting light energy into electricity in electrochemical photovoltaic cells, the most common form of which, dye sensitized solar cells (DSSCs), can offer both flexibility and transparency. Their efficiencies are now comparable with amorphous silicon solar cells but at a much lower cost. This review covers not only the fundamentals of electrochemical photovoltaic cell operation but also recent advances in research and development for industrial applications. The most recent research topics relating to DSSCs, for example, applications of nanostructured n‐type semiconducting electrodes, ionic liquid electrolytes and graphene and carbon nanotube electrodes are all included. In addition, the storage of electrochemical energy by electrochemical photovoltaic cells has also been reviewed. Copyright © 2010 Society of Chemical Industry     

Movement of the deposit segment in thin layer electrochemical cell - a conjugate dissolution/deposition behavior

In this paper we report a novel phenomenon taking place in the thin layer electrodeposition of Pb. A segment of dendrite deposit, which was segregated from the cathode, moved and shortened spontaneously in the electrochemical cell. We find that this behavior arises from the concurrent electrodissolution and electrodeposition reactions taking place at two ends of the isolated segment of the deposits. A mechanism inducing this phenomenon is suggested.     

On the fractal study of LiMn2O4 electrode surface

Fractal dimension of a LiMn₂O₄ electrode prepared by sol-gel method was determined using electrochemical techniques based on the phenomenon of “diffusion towards electrode surface”. A simple discussion was made on the methodology to understand what is really estimated as the fractal dimension. It was demonstrated that the value of fractal dimension determined based on electrochemical methods is strongly dependent on the electrochemical system situation. This is generally true for all real electrodes involving insertion/extraction processes. This comes from the fact that surface morphology of the electrode is subject of significant changes during the electrochemical experiment.     

碳纳米管在电化学传感器中的应用进展

综述了碳纳米管(Carbon Nanotube,CNT)在电化学传感器研究中的应用进展。重点介绍了CNT电极和CNT修饰电极的制备、电化学特性及应用,并对其在DNA电化学生物传感器方面的应用前景与挑战进行了展望。     

Reticulated vitreous carbon—a new versatile electrode material

The present review discusses the physical, chemical and electrochemical characteristics of Reticulated Vitreous Carbon. A survey is given of the electrochemical applications of this relatively new electrode material, together with trends towards possible future applications.     

氯代有机污染物的电化学还原脱氯降解技术研究进展

氯代有机污染物的电化学还原脱氯降解技术在环境处理等领域有重要作用。从氯代有机物的电还原脱氯机理、有机物结构性质、阴极材料、反应容器等多个方面,介绍了目前国内外在电化学还原脱氯领域的最新进展,并提出了今后值得关注的几个方向。     

Synthesis and electrochemical investigation of azobenzene-substituted porphyrins

The synthesis of azobenzene-substituted porphyrins ( 3a-g ) is described. With respect to possible applications as model systems for photochemical reaction centers the spectroscopic and electrochemical properties of the synthesized compounds were investigated. For compound 3e the obtained spectroscopic and electrochemical data confirm that a light driven electron transfer from a porphyrin to the azobenzene moiety is possible.     

The rotating cylinder electrode: a review of development

Recent developments in the theory and applications of rotating cylinder electrodes are reviewed. Particular attention is paid to the mass transfer behaviour and the development of turbulent flow patterns, and its exploitation in electrochemical reactors for a variety of applications including metal deposition from waste and effluent liquors.     

离子液体在电有机合成中的应用

离子液体独特的全离子结构会导致良好的导电性,成为有潜力的绿色电化学材料.离子液体热稳定性好,不挥发,不燃烧,离子电导率高,电化学窗口宽,适合应用在电化学中.简单介绍了离子液体,并综述了离子液体在电有机合成中的应用研究进展.在电合成中,离子液体由于自身较高的电导而避免了加入电解质对电化学反应的干扰.离子液体在电有机合成中的应用分为有机氧化还原反应、电聚合反应、电解氟化反应.然而,离子液体在电有机合成方面研究的较少,它们作为反应介质应用于电有机合成仍然无法摆脱前人的成果.     

离子液体在电流型电化学气体传感器中的应用

离子液体作为一种新型电解质,有着优良的电化学性能,有望解决电化学气体传感器在高温、高湿下使用寿命短、稳定性差等问题。本文按照被检测气体种类对离子液体作为电解质的电流型电化学气体传感器进行了综述,就其在不同气体中的灵敏度、电化学响应、稳定性、气体传质、反应机理等方面的研究加以阐述。从灵敏度、响应时间、稳定性、选择性、抗干扰性等方面介绍了离子液体电化学气体传感器的优缺点,并对目前离子液体电化学气体传感器研究中存在的不足做了评述。同时指出未来应该加强在大气条件下电化学气体传感器性能、响应机理和电化学反应历程的研究。     

电化学技术与环境保护

综述了电化学清洁能源体系、电化学清洁工艺、污染物的去除与回收以及电化学传感器的应用与进展，着重评述了旨在提高电化学技术对环境保护能力的电化学工艺及装置的研究状况与发展方向，分析了各类化学电源、电化学传感器的性能及应用前景。