Journal of Applied Electrochemistry

A non-cyanide rose golden electroplating system was investigated in this work. The electroplated layer of Cu–Zn–Sn alloy was also investigated using a disodium ethylenediamine tetraacetate (EDTA·2Na) system, in which CuSO4·5H2O, ZnSO4·7H2O and Na2SnO3·3H2O were the main salts. EDTA·2Na acted as a complexing agent. Finally, NaOH acted as a buffering agent in the electroplating solution. The effects of different electroplating solutions on colour, micro-topography, composition and phase structure of the electroplated layer was analysed by photo analysis, SEM, EDS and XRD. Meanwhile, different electroplating solutions were analysed and compared by electrochemical analysis and UV–Vis, FTIR and NMR spectroscopy. A rose golden electroplated layer of Cu–Zn–Sn alloy could be obtained by adjusting the amount of the main salts. The composition of the electroplated layer was 98.81% Cu, 0.77% Zn and 0.42% Sn. Moreover, the electroplated layer was composed of regular 50–100 nm particles. The composition of the ternary alloy-electroplated layer was Cu, Cu5Zn8 and Cu10Sn3 phase. At the same time, the cathode only had a single deposition peak at − 1.22 V by electrochemical analysis of the electroplating solution. UV, IR and NMR analyses show that a chelate was formed with EDTA·2Na and metal ions in an alkaline environment. These results may provide a theoretical guidance for a new technology for Cu–Zn–Sn alloy electrodeposition.

The characteristics and mechanism of the hydrogen evolution reaction on a nickel sulphide electrode incorporating molybdenite particles are described. At 25°C the overpotential for the reaction is 300 mV lower than that of the mild steel cathodes used in unipolar electrolysers. The material shows good stability under long term operation.

This paper reports the influence of composition of mixed solvent electrolyte composition on the discharge capacity and charge–discharge cycle life of lithium metal/amorphous V2O5–P2O5 (95:5 in molar ratio) cells. The solvents used were ethylene carbonate (EC), propylene carbonate (PC), 2-methyltetrahydrofuran (2MeTHF) and THF. LiAsF6 was used as the solute. The electrolyte solutions examined here contain ternary and quaternary mixed systems. The purpose of this work is to obtain an electrolyte solution which realizes a higher rate capability and/or a longer cycle life than the previously studied EC:PC:2MeTHF (15:70:15) ternary mixed system. Of the electrolyte systems examined here, the EC:PC:2MeTHF (30:40:30 in volume) ternary mixed solvent system showed the best cell performance. In addition, a heating test was carried out on an AA- size lithium cell with EC:PC:2MeTHF (30:40:30) as a fundamental abuse test to ensure cell safety.

The growth kinetics of electrogenerated hydrogen, oxygen and chlorine gas bubbles formed at microelectrodes, were determined photographically and fitted by regression analysis to the equation;r(t)=βt x , wherer(t) is the bubble radius at timet after nucleation,β the ‘growth coefficient”, andx the ‘time coefficient’. The coefficientx was found to decrease from a short time (< 10 ms) value near unity, typical of inertia controlled growth, through 0.5, characteristic of diffusional control, to 0.3, expected for Faradaic growth, at long times (\s> 100 ms). The current efficiency for bubble growth increased with bubble lifetime, reflecting the decrease in local dissolved gas supersaturation. The pH dependency of the bubble departure diameter indicated that, in surfactant-free electrolytes, double layer interaction forces between the negatively charged hydrogen evolving cathode or positively charged oxygen/chlorine evolving anode and positively (pH \s< 2) or negatively (pH \s> 3) charged bubbles, were the determining factor. The effect of addition of an increasing concentration of cationic (DoTAB) or anionic (SDoS) surfactant was to progressively reduce the pH effect on departure diameter, due to surfactant adsorption on the bubble and, to a lesser extent, on the electrode.

Pt-based bimetallic alloys have attracted intensive interests as highly efficient and stable heterogeneous catalysts for fuel cell applications, and searching flexible free-standing nanomembranes has been on the research focus because of their promising applications in catalysis, nanoelectronics, batteries, and sensing. Herein, a flexible free-standing paper composed of FePt alloy nanoparticles on nitrogen-doped paper (FePt–NG paper) has been developed as integrated electrode towards electrocatalytic oxidation of formic acid. It is found that, N doping is beneficial for the well dispersion of FePt nanoparticles on NG paper. The synergistic effect between Fe and Pt, as well as N doping effect simultaneously assures the improved catalytic activity of FePt–NG paper, making it the promising flexible electrode for application in fuel cell system. Moreover, the synthesis strategy could be used for the construction of other free-standing electrode towards catalysis, sensing, and battery applications.

The electrochemical hypochlorination of allyl chloride has been studied. It was found that the reaction is best effected using 1 to 1.5 N HCl as the electrolyte, introducing allyl chloride as an emulsion and working at low current density (< 150 mA cm−2).

Bài báo mô tả một loại điện cực đối cực bằng feltgraphite mới để sử dụng trong pin dòng chảy redox và các hệ thống điện hóa khác. Điện cực mới này có cách tiếp cận độc đáo trong thiết kế điện cực đối cực, sử dụng vật liệu polymer không dẫn điện, không có carbon đen làm nền tảng. Đổi mới này cho phép giảm đáng kể thời gian xử lý và chi phí so với các điện cực composite polymer carbon thông thường được sử dụng trong các hệ thống pin đối cực. Độ dẫn điện của cụm điện cực mới tương tự như các điện cực đối cực thông thường, tuy nhiên, nó cho thấy sự cải thiện đáng kể về tính chất cơ học. Chức năng của các điện cực mới này đã được đánh giá trong ứng dụng pin redox vanadi và kết quả cho thấy hiệu suất tương đương với các vật liệu composite thông thường. Một lợi thế vận hành quan trọng là các phản ứng bên cạnh dẫn đến sự xuống cấp của phụ gia dẫn điện trong vật liệu nền điện cực (tức là, sự tách lớp điện cực do sự phát sinh CO2) trong quá trình sạc quá mức của cell đã được loại bỏ, làm cho các điện cực này bền hơn so với các thiết kế thông thường. Cho đến nay, các điện cực đối cực này đã được áp dụng trong các cell redox vanadium nhưng thiết kế và tính chất của chúng hứa hẹn nhiều ứng dụng hơn trong nhiều loại pin dòng chảy redox và hệ thống cell điện hóa đối cực khác.

Binary and ternary Pt-based catalysts were prepared by the Pechini–Adams modified method on carbon Vulcan XC-72, and different nominal compositions were characterized by TEM and XRD. XRD showed that the electrocatalysts consisted of the Pt displaced phase, suggesting the formation of a solid solution between the metals Pt/W and Pt/Sn. Electrochemical investigations on these different electrode materials were carried out as a function of the electrocatalyst composition, in acid medium (0.5 mol dm−3 H2SO4) and in the presence of ethanol. The results obtained at room temperature showed that the PtSnW/C catalyst display better catalytic activity for ethanol oxidation compared to PtW/C catalyst. The reaction products (acetaldehyde, acetic acid and carbon dioxide) were analyzed by HPLC and identified by in situ infrared reflectance spectroscopy. The latter technique also allowed identification of the intermediate and adsorbed species. The presence of linearly adsorbed CO and CO2 indicated that the cleavage of the C–C bond in the ethanol substrate occurred during the oxidation process. At 90 °C, the Pt85Sn8W7/C catalyst gave higher current and power performances as anode material in a direct ethanol fuel cell (DEFC).