Electrochemistry Communications最新文献

This study investigates the deoxidation process of low-grade titanium scrap through molten salt electrolysis induced by overpotential. The research focuses on understanding the efficiency and mechanisms involved in the deoxidation of titanium scrap, utilizing induced overpotential as a key parameter. The analysis includes a detailed examination of the molten salt deoxidation process, with emphasis on electrochemical reactions and overall performance. The findings contribute valuable insights into the application of induced overpotential in enhancing the deoxidation of low-grade titanium scrap through molten salt electrolysis. This research contributes to the optimization of titanium recycling processes, with potential implications for sustainable and resource-efficient metallurgical practices. The induction of overvoltage phenomena was intentionally introduced to achieve an oxygen separation efficiency beyond thermodynamic limits. Furthermore, the correlation between electrochemical factors, formation electrode potential, and oxygen removal efficiency was elucidated. The initial titanium scraps, characterized by an oxygen concentration of 5500 ppm and a purity of 98.2 %, underwent a significant enhancement in characteristics, reaching 1850 ppm of oxygen concentration and 98.97 % purity after the first electrolysis process. In summary, this study presents a comprehensive approach to the separation and purification of titanium from low-grade scraps, by molten salt electrolysis.

In this work, a new and convenient fabrication process for screen-printed reduced graphene oxide-molybdenum disulfide electrode (SPrGO-MoS₂E) was proposed. Reduced graphene oxide-molybdenum disulfide (rGO-MoS₂) composite was hydrothermally synthesized and then dispersed in deionized water and ethanol with a ratio of 2:3 (v/v) to form a conductive suspension. The suspension was then blended with carbon paste at a ratio of 0.1:9.9 (g/g) to obtain a screen-printable rGO-MoS₂ conductive ink. An electrochemical sensing electrode was formed by screening this conductive ink onto a polyethylene terephthalate substrate. The characteristics of this electrode were investigated by scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffractometry, Raman spectroscopy, and electrochemical impedance spectroscopy. Overall, the conductive suspension comprising the rGO-MoS₂ composite showed higher electrochemical sensing performance compared with electrodes containing only rGO or MoS₂. Cyclic voltammetry revealed that the SPrGO-MoS₂ electrode exhibited excellent electrochemical sensing performance toward several electroactive species, namely, potassium hexacyanoferrate (III) ([Fe(CN₆)]^3−/4−), nicotinamide adenine dinucleotide (NAD⁺/NADH), and hydrogen peroxide (H₂O₂) dissolved in 0.1 M PBS (pH 7.4). The limits of detection for [Fe(CN₆)]^3−/4−, NAD⁺/NADH, and H₂O₂ were 0.34, 0.25, and 1.36 μM, respectively. In addition, the reproducibility, repeatability, and stability determined from the relative standard deviations (RSDs, n = 7) of these analytes were less than 12.1 %, 8.6 %, and 7.4 %, respectively. Therefore, the ready-to-use SPrGO-MoS₂E could be an alternative material for advanced chemical and biological sensing applications.

In the current study, the CN-CD30V10A battery tester, K-type temperature sensor, and RS485 are utilized to perform charging and discharging tests on the Panasonic 21,700 lithium-ion battery at various rates. The voltage and temperature changes are measured in real-time, with the data transmitted to the computer via RS485. Then a micro-thermal resistance method is proposed to calculate the equivalent thermal resistance of the cell core along the axial positive and negative poles, as well as along the radial outer circumference surface under anisotropic conditions. Based on the experimental results and the equivalent thermal resistance, an electrothermal coupling model is established for battery internal temperature estimation, taking into account anisotropy and temperature effects on heat transfer. Through the integration of the model and externally measured temperature, the internal temperature is accurately estimated. Moreover, the proposed model (Root-Mean-Square Error, RMSE=0.329) exhibits a significant improvement in accuracy compared to equivalent circuit model (RMSE=1.08), extended Kalman filter (RMSE=0.95), network extended Kalman filter (RMSE=0.58), and neural network unscented Kalman filter (RMSE=0.61). Specifically, the model achieves an approximately 76 % to 228 % reduction in RMSE compared to these methods.

Cathodic protection (CP) in combination with organic coating is applied as a secondary technique to mitigate corrosion of buried steel in an effort to prolong the lifespan of the buried steel pipeline. This study was aimed at developing and applying an adequate technique for monitoring the electrochemical behaviour of buried steel in the presence of CP. A modified voltammetry procedure was applied on carbon steel immersed in simulated soil solution for four days under open circuit potential (OCP) before applying CP for further ten days. Electrochemical impedance spectroscopy (EIS) was also applied at various time intervals to investigate the electrochemistry at the steel/solution interface. The voltammetry experiments revealed that the corrosion rate peaked at 680 µm/yr after three days of being subjected to OCP and then decreased to 411 µm/yr on day four as a result of a passive layer development on the steel surface. The corrosion rate was reduced from 411 µm/yr to 8 µm/yr as result of CP application before fluctuating between 21 and 40 µm/yr. The examination of steel surface via x-ray diffraction revealed the presence of calcareous deposit which resulted due to the application of cathodic protection.

Reversible proton ceramic electrochemical cells (R-PCECs) are of great interest as efficient energy conversion device. Optimization of structural design can enhance the mechanical properties and gas transport of the cells, resulting in improved electrochemical performance. In this study, we developed a 7-channel micro-monolithic R-PCEC for the first time, with uniform channel distribution and smaller gas diffusion pathway length using phase inversion/extrusion technique. The assembled cell with Ni-BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3-δ (Ni-BZCYYb, fuel electrode support) | BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3-δ (BZCYYb, electrolyte) | PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ (PBSCF, air electrode) structure showed a peak power density of 0.94 W cm⁻² at 700 °C in fuel cell mode and electrolysis current density of 2.17 A cm⁻² at 700 °C with an operating voltage of 1.3 V. Additionally, electrochemical impedance spectroscopy (EIS) further indicated that the diffusive polarization of the structured cell was effectively reduced compared to single-channel counterpart.

Common methods based on enzymatic approaches for uric acid (UA) have potential issues such as limited detection range, low linearity, and susceptibility to interference. Our study focuses on enhancing the sensitivity and selectivity of detecting UA by decorating carbon nanotubes (CNTs) with bimetallic platinum-cobalt nanoparticles (PtCo/CNTs) using an adsorbing-thermal reducing method for electrochemical analysis. Physical characterizations are employed to confirm its structural and element compositions. Then, an electrochemical biosensor based on screen printed electrode (SPE) modified with PtCo/CNTs was constructed for UA determination. PtCo/CNTs modified SPE (PtCo/CNTs@SPE) demonstrates significant electrochemical activity and selectivity toward UA detection due to the synergistic effect between PtCo nanoparticles and CNTs, and the excellent electrical conductivity. Under optimized conditions, the current response of UA at the PtCo/CNTs@SPE presented linear dependence on the concentration, ranging from 0.1 µM to 3000.0 µM with a low limit of detection of 0.05 µM. In addition, the selectivity, stability, and practical applications of the as-prepared sensor are also explored.

Determining the phase-transition temperature is crucial in the design of molten salt reactors, as operational temperatures need to be established considering the safety margins related to the thermodynamic stability of the molten salt system. This study introduces a novel approach to determine the phase-transition temperature based on rapid electrical conductivity measurements using a microsecond-scale staircase voltammetry technique. The phase-transition temperature is determined near distinct points where the electrical conductivity abruptly changes, indicating phase transitions. The phase-transition temperatures of three LiCl–KCl molten salt systems, determined using the proposed approach based on electrical conductivity measurements, are with relative errors less than 3% compared with reported phase transition data based on conventional thermal analysis techniques.

Preventing the accumulation of water in the gas diffusion layer (GDL) proves effective in enhancing the performance of polymer electrolyte fuel cells (PEFCs). To understand the water transport phenomena in GDLs and channels of PEFCs, cell hardware for operando synchrotron X-ray radiography was developed with a 100 mm channel length, facilitating the separate quantification of liquid water in the cathode and anode GDLs. The presence of liquid water in the cathode and anode GDLs was confirmed during operation with a supply of dry gas in a counter-flow configuration. Furthermore, the amount of liquid water in the cathode and anode GDLs increased toward the cathode inlet, while the amount of water in the cathode and anode channel regions increased toward each outlet. The liquid water distribution in the GDLs along the channel direction can be attributed to water transport from cathode to anode (back-diffusion), decreasing toward the anode outlet. Therefore, conducting radiography experiments aligned parallel to the GDLs and perpendicular to the channel could provide valuable insights for a more comprehensive understanding of water transport in cells.

The oxygen evolution reaction (OER) on the TiO₂ surface at the solid–liquid interface was observed in real-time and operando using fluorescence-yield X-ray absorption spectroscopy (XAS) in the soft X-ray region. The OER was observed during a potential sweep with UV light on or off, focusing on the oxygen K-edge XAS. Although conventional XAS measurements require long measurement times, the spectra during the reaction were obtained every 3 s in the present experiment via wavelength-dispersive XAS technique. An increase in the X-ray absorption intensity at approximately 533.8 eV was observed during the potential sweep only with UV light on. The observed spectral change is discussed in relation to the reaction mechanism of the OER. The present technique can be applied to a wide range of analyses of (photo-) electrocatalysis and electrochemical reactions at solid–liquid interfaces to observe their products and intermediates during the reaction.

The development of MXenes using Lewis acidic salts for etching (MS-MXenes) in molten salts presents a novel, fluorine-free method attracting considerable interest. However, the behavior of various MS-MXenes and their derivatives in aqueous environments remains largely unexplored. Particularly, vanadium-based MXenes demonstrate intriguing properties in Zn ion aqueous electrolytes. Herein, a fluorine-free V₂CT_x MXene@VO_x is synthesized by molten salt etching under an argon atmosphere. The electrochemical properties of V₂CT_x@VO_x are tested in various aqueous electrolytes, including Zn(TFSI)₂, ZnSO₄, ZnBr₂, ZnAc₂, and ZnCl₂ solutions. The V₂CT_x@VO_x shows high redox capacities in all these Zn ion electrolytes, with the peak performance observed in 1 M ZnBr₂, achieving a maximum capacity of 172 mAh g⁻¹ at 1 mV s⁻¹. This performance rivals that of V₂CT_x MXene prepared through wet-chemical methods. These results underscore the potential of MS-MXenes materials in aqueous energy storage applications.