Russian Journal of Electrochemistry最新文献

Abstract

A paste composition for inkjet 3D-printing based on the NiO–Ce_0.8Gd_0.2O₂-composite is suggested and an anode billet for a solid-oxide fuel cell of planar geometry is developed using the direct inkjet 3D-printing. Effect of the printing mode and thermal annealing on the morphology and structure of the samples is studied. The anode billet is reduced and the resulting sample is characterized by a number of physicochemical methods.

Solid solutions CsAg₄Br_{3 – х}I_{2 + х} (x = 0.38; 0.50; 0.68) are prepared by solid-state synthesis; the single phase of the products is confirmed using the methods of X-ray diffraction and differential scanning calorimetry. The studies of electrotransport characteristics of CsAg₄Br_{3 – х}I_{2 + х} involve measuring the ionic conductivity by the four-probe method in the temperature interval from –50 to +120°C and estimating its electronic component by the Hebb–Wagner method. It is shown that in the studied interval of compositions, the ionic conductivity of CsAg₄Br_{3 – х}I_{2 + х} solid solutions is practically independent of x, approaching the conductivity of the well-known superionic conductor RbAg₄I₅. The activation energy of conduction is found to be about 10 kJ mol^–1 for all compounds studied. The oxidation potential determined by the method of stepwise polarization for CsAg₄Br_{3 – х}I_{2 + х} solid solutions is considerably higher as compared with RbAg₄I₅, being in the range of 0.75–0.78 V (vs. Ag⁰/Ag⁺). The high electrochemical characteristics of CsAg₄Br_{3 – х}I_{2 + х} (0.38 ≤ x ≤ 0.63) and the absence of polymorphic transitions in the considered interval from –160°С to the melting point (175–178°С) make these materials promising for the use in electrochemical devices, especially in low-temperature applications.

Perovskite-like materials with mixed ionic and electronic conductivity are considered as promising functional materials for proton-ceramic electrochemical devices. In the present work, a solid-solution series La_0.9Sr_0.1Sc_{1 – x}Mn_xO_{3 – δ}, where scandium ions in the B-cation position are gradually replaced by manganese ions, was obtained and studied for the first time. The obtained materials were certified by X-ray phase analysis, scanning electron microscopy, and energy-dispersive microanalysis. The dopant influence on the studied materials’ sintering ability and morphology is elucidated. The electrical conductivity of the solid solutions as a function of temperature and gas phase humidity was investigated by the dc four-probe method.

Gastric cancer (GC) is one of the considered enormously important cancer types in the world. A large number of mortality rates have revealed that there is a massive shortage in the prognosis and treatment of GC because the majority of GC cases are identified at an advanced stage. In this regard, the rapid platform for non-invasive detection of GC cells through the analysis of GC biomarkers in the first stages with high sensitivity is essential for the success in the treatment of GC. In recent years, different types of electrochemical immunosensors as efficient sensing devices with benefits including accuracy, reproducibility and low cost have played an extremely significant role in the monitoring of GC. One of the significant issues in the development of electrochemical immunosensors is to increase the system’s sensitivity. A variety of nanomaterials based on carbon-based, silica-based and metallic-based nanomaterials have been used as sensing platforms on the different types of electrochemical electrodes for improving the properties of biodevices. This review highlighted the new progress and technical breakthroughs comprising electrochemical immunosensor for the determination of GC biomarkers including CA19-9, CA72-4, CA125 and CEA. In diverse matrices and proved how nanoprobes could enhance the performance of electrochemical immunsensing approaches.

The stability of microtubular (MT) membranes based on Ba_0.5Sr_0.5Co_{0.8 – x}Fe_0.2Mo_xO_{3 – δ} oxides (BSCFMx) prepared by the phase inversion technique is studied. It is shown that the MT membranes with the BSCFMx composition exhibit long-term stability and resistance to thermal cycling in the air/helium gradient. The maximum oxygen fluxes were obtained for MT membranes with the composition Ba_0.5Sr_0.5Co_0.75Fe_0.2Mo_0.05O_{3 – δ} (({{J}_{{{{{text{O}}}_{2}}}}}) = 7.6 mL cm^–2 min^–1 at T = 850°С and pO_2.1 = 0.21 atm). A detailed equilibrium phase diagram for the BSCFM5 oxide is obtained. The absence of undesired phase transitions is demonstrated.

Biomass-derived carbon material has the advantages of economy and high reversible capacity, and become the research hotspot of anode material for sodium-ion batteries (SIBs). Herein, a facile process to prepare carbon material derived from pyrolysis of cotton stalks was reported. As an anode material for SIBs, the sample shows reversible capacity of 76 mA h g⁻¹ after 500 cycles at 0.05 A g⁻¹. In addition, it has specific capacity of 70 mA h g⁻¹ after 1000 cycles at a current density of 0.1 A g⁻¹. This paper provides a new idea to produce carbon material from biomass waste for energy storage and makes a certain contribution to the sustainable development of waste resources.

In this work, an experimental module for hydrogen purification based on nickel capillaries was fabricated. The module was tested by varying the temperature and the difference in the partial pressure of hydrogen on the supply and permeate sides of the capillaries. The maximum hydrogen flow obtained using a module based on 7 nickel capillaries with a wall thickness of 50 µm was 37.2 mL/min at a temperature of 900°C and a hydrogen pressure of 0.9 atm. The stability of the hydrogen flow to thermal cycling in a temperature range 600–800°С for 55 h was demonstrated.

The structural characteristics of loose zinc deposits obtained in pulse-potential modes are calculated using a phenomenological model. Increasing the duty cycle leads to intensified anodic dissolution during pauses and obtaining of denser deposits, due to the formation of dendrites with fewer tips, yet, a larger diameter as compared to the deposits obtained in the potentiostatic mode. The linear dependence of the diameter of the tips of dendrites forming a loose zinc deposit on the duty cycle is found. There is a critical time corresponding to the achievement of zero deposit growth rate when the metal deposited during the pulse will completely dissolve during the pause.

A series of planar billets of NiO/Ce_0.8Gd_0.2O₂ (NiO/GDC) anodes for solid oxide fuel cells are fabricated by the method of microdrop 3D printing using a pneumatic dispenser. The porosity and the coefficient of sintering-induced shrinkage of anode billets are studied as a function of their preparation method. The anode billets are reduced to obtain Ni/Ce_0.8Gd_0.2O₂ cermet and the thus obtained samples are studied as regards the effect of printing parameters on their morphology and structure. It is shown that the use of 3D printing increases the porosity of the Ni/GDC composite from 7 to 23% as compared with the casted samples, on retention of the high conductivity of (2.82 ± 0.06) × 10³ S/cm.

Results of high-temperature oxygen desorption from SrCoO_{3 – δ}-oxide with mixed conductivity composed of obtained using an original quasi-equilibrium oxygen release technique are shown. The measurements are carried out with a characterized powder sample in a tubular reactor. The equilibrium phase diagram of the oxide in the 600–850°C temperature range and partial pressure of oxygen 0.2–6 × 10^–5 atm is constructed. With the help of literature data, a correlation of phase diagram regions with their corresponding structures is obtained.