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1.
In an internal hybrid capacitor, at least one electrode displays battery-like charge/discharge and the other electrode stores charge reversibly at the electric double-layer (EDL). Recently, a plethora of hybrid cells in aqueous electrolytes have been proposed by coupling an EDL electrode with a battery electrode, the latter made from a variety of redox-active/redox-mediator species either dissolved in the electrolyte or adsorbed/immobilized in nanoporous electrodes. This review presents current opinions, discusses challenges, and supplies recommendation about the hybrid cells with aqueous electrolytes and carbon electrodes. 相似文献
2.
If were not by their low electrochemical stability, aqueous electrolytes would be the preferred alternative to be used in electrochemical energy storage devices. Their abundance and nontoxicity are key factors for such application, especially in large scale. The development of highly concentrated aqueous electrolytes, so-called water-in-salt electrolytes, has expanded the electrochemical window of aqueous electrolyte up to 3.0 V (whereas salt-in-water electrolytes normally shows up to 1.6 V), showing that water can be an alternative after all. Many devices, ranging from metal-ion batteries to electrochemical capacitors, have been reported recently, making use of such wider electrochemical stability and enhancing devices energy density. Different salts have also been proposed not only to gain in costs but also to improve physicochemical properties. 相似文献
3.
利用NO2或O2作为氧化剂,研究了氧化锌在Au(111)和Cu(111)上的生长和结构。NO2表现了更好的氧化性能,有利于有序氧化锌纳米结构或薄膜的生长。在Au(111)和Cu(111)这两个表面上,化学计量比氧化锌都形成非极性的平面化ZnO(0001)的表面结构。在Au(111)上,NO2气氛下室温沉积锌倾向于形成双层氧化锌纳米结构;而在更高的沉积温度下,在NO2气氛中沉积锌则可同时观测到单层和双层氧化锌纳米结构。O2作为氧化剂时可导致形成亚化学计量比的ZnOx结构。由于铜和锌之间的强相互作用会促进锌的体相扩散,并且铜表面可以被氧化形成表面氧化物,整层氧化锌在Cu(111)上的生长相当困难。我们通过使用NO2作为氧化剂解决了这个问题,生长出了覆盖Cu(111)表面的满层有序氧化锌薄膜。这些有序氧化锌薄膜表面显示出莫尔条纹,表明存在一个ZnO和Cu(111)之间的莫尔超晶格。实验上观察到的超晶格结构与最近理论计算提出的Cu(111)上的氧化锌薄膜结构相符,具有最小应力。我们的研究表明,氧化锌薄膜的表界面结构可能会随氧化程度或氧化剂的不同而变化,而Cu(111)的表面氧化也可能影响氧化锌的生长。当Cu(111)表面被预氧化成铜表面氧化物时,ZnOx的生长模式会发生变化,锌原子会受到铜氧化物晶格的限域形成单位点锌。我们的研究表明了氧化锌的生长需要抑制锌向金属基底的扩散,并阻止亚化学计量比ZnOx的形成。因此,使用原子氧源有利于在Au(111)和Cu(111)表面上生长有序氧化锌薄膜。 相似文献
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本文研究BMIPF6离子液体中Au(111)和Pt(111)表面Ge的电沉积行为. 循环伏安法测试结果表明,在含0.1 mol·L-1 GeCl4的BMIPF6溶液Au(111)和Pt(111)表面均有两个与Ge沉积过程相关的还原峰. 第一个还原峰包含了Ge4+还原成Ge2+及Ge的欠电位沉积,第二个还原峰对应Ge的本体沉积. 现场扫描隧道显微镜研究结果表明,Ge在Au(111)和Pt(111)表面均有两层欠电位沉积. 第一层欠电位沉积厚度约为0.25 nm、形貌平整、带有缝隙的亚单层结构. 第二层欠电位沉积形貌相对粗糙的点状团簇结构. 该欠电位沉积过程伴随表面合金化. 相似文献
6.
Satoshi Kaneco Kenji Iiba Kiyohisa Ohta Takayuki Mizuno 《Journal of Solid State Electrochemistry》1999,3(7-8):424-428
The electrochemical reduction of CO2 at a Cu electrode was investigated in a methanol-based electrolyte using such potassium supporting salts as CH3COOK, KBr, KI and KSCN at extremely low temperature (−30 °C). The main products obtained from CO2 by the electrochemical reduction were methane, ethylene, ethane, carbon monoxide and formic acid. The maximum Faradaic efficiency
of ethylene was 19.9% in KI/methanol-based catholyte at −3.0 V vs. Ag/AgCl saturated KCl. The best methane formation (27.0%)
was obtained in CH3COOK/methanol electrolyte at −3.0 V. In the system containing a potassium halide, the efficiency of hydrogen formation, being
a competitive reaction against CO2 reduction, was suppressed to less than 8.1%. The product selectivity of the electrochemical reduction of CO2 in methanol was greatly affected by the anionic species. This research can contribute to the large-scale manufacturing of
useful organic products from readily available and cheap raw materials: CO2-saturated methanol from industrial absorbers (the Rectisol process).
Received: 11 November 1998 / Accepted: 1 February 1999 相似文献
7.
Ján Labuda Pavol Tarapčík Adela Kotočová Jozef Šima 《Monatshefte für Chemie / Chemical Monthly》1992,123(8-9):693-699
Summary Half-wave potentials for a one-electron reduction of copper(II) complexes containing polydentate ligands can be calculated using the equationE
1/2=E
0(Cu2+/+)+
i
j
E
i where E
i are contributions related to the electronic and steric properties of the ligands. The values of 18 E
i contributions are presented and explained, and the effect of the solvents on the half-wave potentials is exemplified.Dedicated to Prof. Dr. Viktor Gutmann to his 70th birthday 相似文献
8.
Two new reduced Schiff base ligands, [HL1 = 4-{2-[(pyridin-2-ylmethyl)-amino]-ethylimino}-pentan-2-one and HL2 = 4-[2-(1-pyridin-2-yl-ethylamino)-ethylimino]-pentan-2-one] have been prepared by reduction of the corresponding tetradentate unsymmetrical Schiff bases derived from 1:1: 1 condensation of 1,2-ethanediamine, acetylacetone and pyridine-2-carboxaldehyde/2-acetyl pyridine. Four complexes, [Ni(L1)]ClO4 (1), [Cu(L1)]ClO4 (2), [Ni(L2)]ClO4 (3), and [Cu(L2)]ClO4 (4) with these two reduced Schiff base ligands have been synthesized and structurally characterized by X-ray crystallography. The mono-negative ligands L1 and L2 are chelated in all four complexes through the four donor atoms to form square planar nickel(II) and copper(II) complexes. Structures of 3 and 4 reveal that enantiomeric pairs are crystallized together with opposite chirality in the nitrogen and carbon atoms. The two CuII complexes (2 and 4) exhibit both irreversible reductive (CuII/CuI; Epc, −1.00 and −1.04 V) and oxidative (CuII/CuIII; Epa, +1.22 and +1.17 V, respectively) responses in cyclic voltammetry. The electrochemically generated CuI species for both the complexes are unstable and undergo disproportionation. 相似文献
9.
《Arabian Journal of Chemistry》2022,15(12):104375
Dopamine (DA), a critical catecholamine neurotransmitter, is responsible for normal functioning of body. Its dysregulation causes cognitive disturbances. Thus, an efficient real time monitoring of DA in clinical samples is required. Herein we report a novel nanocomposite comprising of carbon nanocoils (CNC) and copper tetra(p-methoxyphenyl)porphyrin (CuTMePP) for efficient electrochemical detection of dopamine that was characterized by FTIR, UV/vis., Raman, XRD, SEM, TEM and energy dispersive X-ray techniques. The electrochemical studies were performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy and differential pulse voltammetry (DPV). CNC/CuTMePP/glassy carbon (GC) has demonstrated two linear trends between current and concentration i.e. 0.1 to 100.0 µM and 100.0 to 800.0 µM. Limit of detection (LoD), limit of quantification (LoQ) and sensitivity of the electrode in the concentration range of 0.1 to 100.0 µM was 50.0 nM, 167.0 nM and 1.76 µAµM-1cm?2, respectively using CV. With DPV, the LoD, LoQ and sensitivity were found to be 64.0 nM, 211.0 nM and 0.75 µAµM-1cm?2, respectively obtained in a concentration range of 0.1 to 100.0 µM. The as prepared sensor exhibited good intra/inter-day stabilities, reproducibility, excellent recovery in the human serum samples, presented significant clinical dopamine detection and showed comparable results with other work in literature. 相似文献
10.
A. V. Rudnev E. B. Molodkina A. I. Danilov Yu. M. Polukarov J. M. Feliu 《Russian Journal of Electrochemistry》2006,42(4):381-392
The kinetics of underpotential deposition, three-dimensional nucleation, and growth of copper deposits at cathodic overpotentials on a Pt(111) electrode in solutions containing 0.5 M H2SO4, 10 mM CuSO4, and 0–200 mM acetonitrile (AcN) is studied by the cyclic voltammetry, potentiostatic current transients, and scanning probe microscopy methods. At low volume concentrations of acetonitrile ([AcN] ≤ 4 mM), adsorbed acetonitrile molecules accelerate the formation of a co-adsorption lattice of copper adatoms with anions due to local electrostatic effects at the charged interface. At higher concentrations, the underpotential deposition process is hampered, but the desorption of copper adatoms occurs at potentials more positive than those at low acetonitrile concentrations. This effect is attributed to a stabilizing action of acetonitrile molecules situated on the layer of copper adatoms and, in part, on platinum. At [AcN] = 0.4–40 mM, adsorbed acetonitrile molecules accelerate the growth of the bulk copper deposit, but the nucleation stage is hindered. The dependence of the copper amount on the deposition potential at [AcN] = 40 mM exhibits a maximum at 0.15–0.17 V. This effect was previously observed in weakly acid solutions (pH 1.7–3.0) containing no acetonitrile. The maximum rate of the deposit growth corresponds to an optimum number of crystallites (which is not too great) and an optimum distance between the growing centers in conditions of mixed kinetics “diffusion + electron transfer.” A substantial number of complexes Cu(I)-AcN forms at high acetonitrile concentrations. 相似文献
11.
本文应用第一性原理的密度泛函(DFT)方法,使用DMol3计算程序,对NO在Rh(100)和Rh(111)面上的吸附与分解进行量化计算,力图解决NO在Rh(100)和Rh(111)面上的优选吸附位、直接分解的过渡态和活化能等重要问题. 相似文献
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Electrical double layer capacitors based on ideally polarizable nanoporous carbon electrodes in propylene carbonate with the addition of different 1 M Me3EtNBF4, Me2Et2NBF4, MeEt3NBF4, Et4NBF4, Et3PrNBF4 and Et3BuNBF4 electrolytes have been tested by cyclic voltammetry, chronoamperometry and electrochemical impedance methods. The limits of ideal polarizability, low-frequency limiting capacitance and series resistance, time constant, Ragone plots (energy density vs. power density dependencies) and other characteristics have been discussed. The influence of the electrolyte molar mass on the electrochemical characteristics of the nanoporous carbon electrode cells has been established. The applicability limits of the Srinivasan and Weidner model have been tested. 相似文献
14.
The initial kinetics of electrochemical deposition of palladium on an Au(111) electrode in 0.1 M H2SO4 solution containing K2PdCl4 have been investigated quantitatively by cyclic voltammetry (CV) and potentiostatic current transient measurements. A cathodic current maximum was observed in the initial stage of Pd deposition process in 0.1 mM K2PdCl4 solution. The analysis shows that the deposition of palladium in this solution proceeds by an instantaneous nucleation and two-dimensional (2D) growth mode. When the concentration of K2PdCl4 became higher, a potential-dependent cathodic current ‘plateau’ after the current maximum was observed. Simple nucleation-growth models cannot fit the transients in the region of the ‘current plateau’. The present current transient results were discussed in comparison with the results obtained by in situ scanning tunneling microscopy (STM). 相似文献
15.
本文针对BMIPF6 和OMIPF6两种离子液体,在电极表面远离零电荷电位且以负电荷表面电位下,运用AFM力曲线详细地研究了其与Au(111)单晶电极界面所形成的层状结构与温度的关联. 在15 ~ 40 oC的温度范围内,温度越低其离子液体层状结构越稳定. 温度对OMIPF6离子液体层状结构的稳定性和数目的影响较BMIPF6缓和:温度变化5 oC,OMIPF6靠近表面第一层层状结构的力值变化仅为1 ~ 2 nN,而BMIPF6第一层层状结构的力值变化为3 ~ 5 nN;较低温下,BMIPF6中层状结构的数目有所增加,而OMIPF6的层状数目始终保持两层,且随温度的变化并不敏感. 这可归因于两种离子液体的阳离子尺寸以及与电极表面的作用方式和强度不同;同时,OMIPF6较粘稠,其热运动受温度的影响不甚敏感. 相似文献
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The adsorption and thermal decomposition of ketene on Si(l 11)-7 × 7 were investigated using various surface analysis techniques. When the surface was exposed to ketene at 120 K, two CO stretching modes at 220 and 273 meV appeared in HREELS, corresponding to two adsorbed ketene states. After the sample was annealed at ?250 K, the 273 and the 80 meV peaks vanished, indicating the disappearance of one of the adsorption states by partial desorption of the adsorbate. In a corresponding TPD measurement, a desorption peak for ketene species was noted at 220 K. Annealing the sample at 450 K caused the decomposition of the adsorbate, producing CHx and O adspecies. Further annealing of the surface at higher temperatures resulted in the breaking of the CH bond, the desorption of H and O species and the formation of Si carbide. The desorption of H at 800 K was confirmed by the appearance of the D2 (m/e = 4) TPD peak at that temperature when CD2CO was used instead of CH2CO. 相似文献
18.
S. Strbac F. Maroun O. M. Magnussen R. J. Behm 《Journal of Electroanalytical Chemistry》2001,500(1-2)
In order to elucidate electronic effects on the oxidation of CO on small Ru clusters, we investigated this reaction on well defined Ru/Au(111) model systems via parallel in-situ STM studies of the structure and electrochemical deposition of Ru on Au(111) in H2SO4 solution and cyclic voltammetry of CO monolayer oxidation on these surfaces. The Ru deposit consists of nanoscale islands, which coalesce with increasing coverage. The Ru saturation coverage depends on the deposition potential, resulting in Ru submonolayer (>0.1 V), (defective) monolayer (≥−0.1 V), and multilayer films (<−0.1 V). At potentials >0.6 V irreversible formation of Ru oxide/hydroxide species is observed, which can be partly reduced in the range 0.4 to 0.0 V. CO stripping commences at ≈0.1 V and occurs over a broad potential range. From the stripping charge a local CO coverage on the Ru monolayer islands of 0.7 ML was estimated. The observed influence of the morphology of the Ru deposit on the CO stripping voltammetry is explained by (local) variations in the CO adsorption energy due to electronic modifications of the Ru film. 相似文献
19.
We develop a theory of the double layer at electrolyte | electrolyte interfaces with account for the finite thickness of the interfacial region. This includes the distribution of ions between the two phases and smooth variation of dielectric properties across the interface. The theory offers simple laws for the dependence of the double layer capacitance on the nature of ions, ionic concentrations and potential, which are in line with experimental observations. The theory shows which parameters reflect the nature of ions and the structure of the interface, and how these parameters can be extracted from the capacitance data. 相似文献
20.
Picoliter-volume aqueous droplets in oil: electrochemical detection and yeast cell electroporation 总被引:1,自引:0,他引:1
An electrochemical detection method was introduced for aqueous droplet analysis in oil phase of microfluidic devices. This method is based on the electrochemical signal difference between aqueous and oil. Applying a low alternating current (AC) voltage to a couple of Au microelectrodes, this method can offer size information and ion concentration range from 0.02 mmol/L to 1 mol/L of tens of picoliter to nanoliter aqueous droplets. Alternatively, applying a relative high AC voltage (18 Vpp) at a frequency of 1 kHz leads to electroporation of yeast cells encapsulated into picoliter droplets. We believe that this simple technique is useful for a number of aqueous droplet-based chemical and biological analyses as well as cell electroporation. 相似文献