Pub Date : 2024-09-10DOI: 10.1149/1945-7111/ad76df
Timothy Lichtenstein, Mark H. Schvaneveldt, Jarrod Gesualdi and Krista L. Hawthorne
Alternatives to the widely-used standard anodic decomposition reference electrodes in molten salts are necessary to enable more easily reproduced thermochemical and electrochemical data in molten salt electrolytes. The class of standard reference electrodes called cathodic decomposition electrodes (CDEs) are easily constructed and can be used to make thermochemical measurements in molten salts more directly compared to anodic decomposition electrodes. The lithium eutectic electrode (LEE) was chosen as a sample test case for validation and was applied to thermochemical measurements of electroactive species in molten LiCl-KCl eutectic. Transient measurements were made to measure the Li+/Li reduction potential at zero current in pure LiCl-KCl eutectic relative to a Li-alloy reference electrode to validate the reference potential of the LEE. Literature-reported electromotive force measurements against Li-alloy reference electrodes were used to generate a relationship between the LEE and the standard chlorine electrode and this relationship was used to evaluate measured and reported formal potential measurements for the LiCl-KCl-GdCl3 system. This work demonstrates the general framework for defining CDEs for any molten salt system and a method for calibrating external reference electrodes against a CDE standard reference electrode, improving the ease of obtaining thermochemical and electrochemical measurements in any molten salt system.
为了更容易地再现熔盐电解质中的热化学和电化学数据，有必要在熔盐中使用广泛使用的标准阳极分解参比电极之外，再使用其他参比电极。被称为阴极分解电极（CDE）的一类标准参比电极易于制造，与阳极分解电极相比，可以更直接地用于熔盐中的热化学测量。我们选择了锂共晶电极（LEE）作为验证样本，并将其应用于熔融锂盐-氯化钾共晶中电活性物种的热化学测量。进行了瞬态测量，测量纯 LiCl-KCl 共晶在零电流下相对于锂合金参比电极的 Li+/Li 还原电位，以验证 LEE 的参比电位。文献报道的针对锂合金参比电极的电动势测量值被用来生成 LEE 与标准氯电极之间的关系，这种关系被用来评估 LiCl-KCl-GdCl3 系统的测量值和报告的正式电势测量值。这项工作展示了为任何熔盐体系定义 CDE 的一般框架，以及根据 CDE 标准参比电极校准外部参比电极的方法，从而提高了在任何熔盐体系中获得热化学和电化学测量的便利性。
{"title":"Cathodic Decomposition Electrodes as Standard Reference Electrodes for Molten Salts: Example of the Lithium Eutectic Electrode for the LiCl-KCl Eutectic","authors":"Timothy Lichtenstein, Mark H. Schvaneveldt, Jarrod Gesualdi and Krista L. Hawthorne","doi":"10.1149/1945-7111/ad76df","DOIUrl":"https://doi.org/10.1149/1945-7111/ad76df","url":null,"abstract":"Alternatives to the widely-used standard anodic decomposition reference electrodes in molten salts are necessary to enable more easily reproduced thermochemical and electrochemical data in molten salt electrolytes. The class of standard reference electrodes called cathodic decomposition electrodes (CDEs) are easily constructed and can be used to make thermochemical measurements in molten salts more directly compared to anodic decomposition electrodes. The lithium eutectic electrode (LEE) was chosen as a sample test case for validation and was applied to thermochemical measurements of electroactive species in molten LiCl-KCl eutectic. Transient measurements were made to measure the Li+/Li reduction potential at zero current in pure LiCl-KCl eutectic relative to a Li-alloy reference electrode to validate the reference potential of the LEE. Literature-reported electromotive force measurements against Li-alloy reference electrodes were used to generate a relationship between the LEE and the standard chlorine electrode and this relationship was used to evaluate measured and reported formal potential measurements for the LiCl-KCl-GdCl3 system. This work demonstrates the general framework for defining CDEs for any molten salt system and a method for calibrating external reference electrodes against a CDE standard reference electrode, improving the ease of obtaining thermochemical and electrochemical measurements in any molten salt system.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1149/1945-7111/ad75be
Allan Lebreton, Jérémy Barbé, Christophe Lethien, Jonathan N. Coleman and Thierry Brousse
Vanadium nitride is a highly promising material for micro-pseudocapacitors when used as a bifunctional thin film, i.e. an electrode material and a current collector, owing to its remarkable electrical and electrochemical properties. However, the specific limitations associated with high-rate cycling remain unclear. In this study, we evaluate how the characteristic time associated with charge/discharge of vanadium nitride films is modified with the film thicknesses using electrochemical impedance spectroscopy and cyclic voltammetry measurements coupled to a semi-empirical model commonly utilized to assess the high-rate behaviour of battery electrodes. Both methodologies are in good agreement and revealed that rate capability of this bi-functional material is limited by the VN electrical conductivity. To confirm this finding, VN thin films were sputtered on platinum current collectors, leading to a six-fold reduction in the characteristic time associated with charge/discharge of the current collectors/electrode material. This underscores the importance of using current collectors even for highly conductive electrode materials.
{"title":"Tuning Deposition Conditions for VN Thin Films Electrodes for Microsupercapacitors: Influence of the Thickness","authors":"Allan Lebreton, Jérémy Barbé, Christophe Lethien, Jonathan N. Coleman and Thierry Brousse","doi":"10.1149/1945-7111/ad75be","DOIUrl":"https://doi.org/10.1149/1945-7111/ad75be","url":null,"abstract":"Vanadium nitride is a highly promising material for micro-pseudocapacitors when used as a bifunctional thin film, i.e. an electrode material and a current collector, owing to its remarkable electrical and electrochemical properties. However, the specific limitations associated with high-rate cycling remain unclear. In this study, we evaluate how the characteristic time associated with charge/discharge of vanadium nitride films is modified with the film thicknesses using electrochemical impedance spectroscopy and cyclic voltammetry measurements coupled to a semi-empirical model commonly utilized to assess the high-rate behaviour of battery electrodes. Both methodologies are in good agreement and revealed that rate capability of this bi-functional material is limited by the VN electrical conductivity. To confirm this finding, VN thin films were sputtered on platinum current collectors, leading to a six-fold reduction in the characteristic time associated with charge/discharge of the current collectors/electrode material. This underscores the importance of using current collectors even for highly conductive electrode materials.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1149/1945-7111/ad7534
Zhefei Zhao, Linlin Zhang, Minghao Chen, Ruopeng Yu, Xuyao Yao, Yinghua Xu, Youqun Chu, Xinbiao Mao and Huajun Zheng
Electrochemical selective dechlorination can be regarded as one of the most promising strategies for generating high-valued chemicals. In the electrochemical dechlorination process of 2-chloro-5-trichloromethylpyridine (TCMP), except the anticipated dechlorination products involving 2-chloro-5-dichloromethylpyridine (DCMP), 2-chloro-5-chloromethylpyridine (CCMP), and 2-chloro-5-methylpyridine (CMP), some unexpected oxygen-incorporated products (6-chloronicotinic acid (CNA) and 6-chloronicotinoyl methyl ester (MCN)) can be obtained. Consequently, understanding the electrochemical dechlorination behavior of TCMP is crucial. Our research revealed that the activated Ag electrodes in halide ion solution exhibit enhanced electrochemical activities for electrochemical dechlorination of TCMP, compared with the pure Ag owing to the increased active specific surface areas and charge transfer. Second, oxygen participation in the reaction is a necessary condition for the formation of oxygen-incorporated products. A 100% selectivity of oxygen-incorporated products can be obtained at the potential of −0.6 V vs Ag/AgCl. Conversely, insufficient oxygen may lead to the potential becoming the determining condition that affects the reaction pathways. A more negative potential (−1.2 V vs Ag/AgCl) is conducive to the formation of dechlorination products with 94.2% conversion and 100% selectivity. This study, for the first time, elucidates the electrocatalyst, atmosphere, and potential-dependent activity and selectivity for the two dechlorination pathways of TCMP.
电化学选择性脱氯可以说是生成高价值化学品的最有前途的策略之一。在 2-氯-5-三氯甲基吡啶（TCMP）的电化学脱氯过程中，除了涉及 2-氯-5-二氯甲基吡啶（DCMP）的预期脱氯产物外，2-氯-5-二氯甲基吡啶（CCMP）和 2-氯-5-三氯甲基吡啶（TCMP）的电化学选择性脱氯产物均可作为高附加值化学品、（CCMP）和 2-氯-5-甲基吡啶（CMP）外，还可以得到一些意想不到的氧掺杂产物（6-氯烟酸（CNA）和 6-氯烟酸甲酯（MCN））。因此，了解 TCMP 的电化学脱氯行为至关重要。我们的研究发现，与纯银相比，在卤化离子溶液中的活化银电极在 TCMP 的电化学脱氯过程中表现出更强的电化学活性，这是由于活性比表面积和电荷转移增加所致。其次，氧参与反应是形成氧结合产物的必要条件。与 Ag/AgCl 相比，在电位为 -0.6 V 时，氧结合产物的选择性为 100%。相反，氧气不足可能导致电位成为影响反应途径的决定性条件。更负的电位（-1.2 V vs Ag/AgCl）有利于形成脱氯产物，转化率为 94.2%，选择性为 100%。这项研究首次阐明了 TCMP 两种脱氯途径中的电催化剂、气氛以及电势对活性和选择性的影响。
{"title":"Oxygen-Controlled Electrocatalysis for Selective Dechlorination of 2-Chloro-5-Trichloromethyl Pyridine on Activated Ag Electrode","authors":"Zhefei Zhao, Linlin Zhang, Minghao Chen, Ruopeng Yu, Xuyao Yao, Yinghua Xu, Youqun Chu, Xinbiao Mao and Huajun Zheng","doi":"10.1149/1945-7111/ad7534","DOIUrl":"https://doi.org/10.1149/1945-7111/ad7534","url":null,"abstract":"Electrochemical selective dechlorination can be regarded as one of the most promising strategies for generating high-valued chemicals. In the electrochemical dechlorination process of 2-chloro-5-trichloromethylpyridine (TCMP), except the anticipated dechlorination products involving 2-chloro-5-dichloromethylpyridine (DCMP), 2-chloro-5-chloromethylpyridine (CCMP), and 2-chloro-5-methylpyridine (CMP), some unexpected oxygen-incorporated products (6-chloronicotinic acid (CNA) and 6-chloronicotinoyl methyl ester (MCN)) can be obtained. Consequently, understanding the electrochemical dechlorination behavior of TCMP is crucial. Our research revealed that the activated Ag electrodes in halide ion solution exhibit enhanced electrochemical activities for electrochemical dechlorination of TCMP, compared with the pure Ag owing to the increased active specific surface areas and charge transfer. Second, oxygen participation in the reaction is a necessary condition for the formation of oxygen-incorporated products. A 100% selectivity of oxygen-incorporated products can be obtained at the potential of −0.6 V vs Ag/AgCl. Conversely, insufficient oxygen may lead to the potential becoming the determining condition that affects the reaction pathways. A more negative potential (−1.2 V vs Ag/AgCl) is conducive to the formation of dechlorination products with 94.2% conversion and 100% selectivity. This study, for the first time, elucidates the electrocatalyst, atmosphere, and potential-dependent activity and selectivity for the two dechlorination pathways of TCMP.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1149/1945-7111/ad7406
D. Nienhues, L. Müller and M. Nowottnick
This paper evaluates the electrochemical properties of aluminum (0.5 w%) copper alloy metallized test chip surfaces with interdigital structures and distances between 3 and 20 μm, regarding sodium chloride and potassium fluoride contamination in the range of 1011–1016 ions per cm2 at high humidity (85%) and high temperature (85 °C). These accelerated tests result in leakage currents and impedance values which show a significant change above a contamination limit value of 1014 ions per cm2 for both salts i.e., the leakage current starts to increase well above a few pico amperes, and the impedance decreases significantly. This contamination level can be seen as a turning point, after which devices can undergo for example signal shifts or corroded metal tracks over lifetime. But not only the start point of an increase in leakage current decides about the harmfulness of the contamination, other important influences are deliquescence and how high the leakage current gets at its maximum. Therefore, even with the same starting point, the risk evaluation is not the same for sodium chloride and potassium fluoride.
{"title":"Influence of Sodium Chloride and Potassium Fluoride on Electrochemical Properties of Aluminum Copper Interdigital Structures","authors":"D. Nienhues, L. Müller and M. Nowottnick","doi":"10.1149/1945-7111/ad7406","DOIUrl":"https://doi.org/10.1149/1945-7111/ad7406","url":null,"abstract":"This paper evaluates the electrochemical properties of aluminum (0.5 w%) copper alloy metallized test chip surfaces with interdigital structures and distances between 3 and 20 μm, regarding sodium chloride and potassium fluoride contamination in the range of 1011–1016 ions per cm2 at high humidity (85%) and high temperature (85 °C). These accelerated tests result in leakage currents and impedance values which show a significant change above a contamination limit value of 1014 ions per cm2 for both salts i.e., the leakage current starts to increase well above a few pico amperes, and the impedance decreases significantly. This contamination level can be seen as a turning point, after which devices can undergo for example signal shifts or corroded metal tracks over lifetime. But not only the start point of an increase in leakage current decides about the harmfulness of the contamination, other important influences are deliquescence and how high the leakage current gets at its maximum. Therefore, even with the same starting point, the risk evaluation is not the same for sodium chloride and potassium fluoride.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1149/1945-7111/ad75bb
Xin Li, Yangwanhao Song and Hengqi Ren
An accurate estimation of the lithium battery’s state of charge (SOC) is critical. The article proposes a dual fractional order multi-innovations cubature Kalman filter (DFOMICKF) algorithm for estimating lithium battery SOC. The algorithm adopts the idea of multiple time scales, where one of the FOMICKF is used to identify the circuit model parameters online in the macro time scale. Another FOMICKF is used to estimate the SOC in the micro time scale, and the circuit parameters updated online in real-time are passed into the estimation of the SOC filter to form an online joint estimation method of SOC and circuit parameters. Finally, multiple algorithms of DFOMICKF, FOMICKF, FOCKF, and CKF are compared and experimented under different working conditions to compare and analyze the estimated SOC errors. It is verified that the proposed algorithm can solve the problems of inaccuracy, poor convergence, and poor robustness of the traditional Kalman filtering algorithm for estimating SOC, which has good research value.
{"title":"State of Charge Estimation of Lithium-Ion Batteries Based on Fractional-Order Model with Mul-ti-Innovations Dual Cubature Kalman Filter Method","authors":"Xin Li, Yangwanhao Song and Hengqi Ren","doi":"10.1149/1945-7111/ad75bb","DOIUrl":"https://doi.org/10.1149/1945-7111/ad75bb","url":null,"abstract":"An accurate estimation of the lithium battery’s state of charge (SOC) is critical. The article proposes a dual fractional order multi-innovations cubature Kalman filter (DFOMICKF) algorithm for estimating lithium battery SOC. The algorithm adopts the idea of multiple time scales, where one of the FOMICKF is used to identify the circuit model parameters online in the macro time scale. Another FOMICKF is used to estimate the SOC in the micro time scale, and the circuit parameters updated online in real-time are passed into the estimation of the SOC filter to form an online joint estimation method of SOC and circuit parameters. Finally, multiple algorithms of DFOMICKF, FOMICKF, FOCKF, and CKF are compared and experimented under different working conditions to compare and analyze the estimated SOC errors. It is verified that the proposed algorithm can solve the problems of inaccuracy, poor convergence, and poor robustness of the traditional Kalman filtering algorithm for estimating SOC, which has good research value.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1149/1945-7111/ad73a6
Rémy Rouxhet, Maxime Loudeche, Ronny Santoro and Joris Proost
Lime holds considerable potential in diverse environmental applications. However, its current production remains highly carbon-intensive, emitting more than one ton of CO2 per ton of lime. To address this issue, recent studies have explored the concept of electrifying the decarbonation of limestone to produce hydrated lime. In this work, a two-compartment electrolysis cell capable of producing Ca(OH)2 has been tested at different currents. Precise pH and Ca2+ concentration measurements demonstrate that the electrolysis setup is able to dissolve CaCO3 and precipitate Ca(OH)2 with near-perfect efficiencies. Notably, it highlights that Faraday’s law and the concept of transport number can be applied to predict both the equilibrium and kinetic behavior of each step of the process in each of the two cell compartments. Moreover, the use of controlled batch additions of CaCO3 in the system, as opposed to one-time excess addition, was assessed to mitigate the fouling of the cationic exchange membrane used to separate the compartments. Finally, based on the experimental findings, key guidelines are proposed to achieve a perfect reaction stoichiometry for each step. These findings pave the way for a more sustainable and environmentally friendly approach to lime production.
{"title":"Low-Temperature Water Electrolysis Under a Sustained pH-Gradient for Electrochemically-Induced Decarbonation of Limestone into Hydrated Lime","authors":"Rémy Rouxhet, Maxime Loudeche, Ronny Santoro and Joris Proost","doi":"10.1149/1945-7111/ad73a6","DOIUrl":"https://doi.org/10.1149/1945-7111/ad73a6","url":null,"abstract":"Lime holds considerable potential in diverse environmental applications. However, its current production remains highly carbon-intensive, emitting more than one ton of CO2 per ton of lime. To address this issue, recent studies have explored the concept of electrifying the decarbonation of limestone to produce hydrated lime. In this work, a two-compartment electrolysis cell capable of producing Ca(OH)2 has been tested at different currents. Precise pH and Ca2+ concentration measurements demonstrate that the electrolysis setup is able to dissolve CaCO3 and precipitate Ca(OH)2 with near-perfect efficiencies. Notably, it highlights that Faraday’s law and the concept of transport number can be applied to predict both the equilibrium and kinetic behavior of each step of the process in each of the two cell compartments. Moreover, the use of controlled batch additions of CaCO3 in the system, as opposed to one-time excess addition, was assessed to mitigate the fouling of the cationic exchange membrane used to separate the compartments. Finally, based on the experimental findings, key guidelines are proposed to achieve a perfect reaction stoichiometry for each step. These findings pave the way for a more sustainable and environmentally friendly approach to lime production.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-08DOI: 10.1149/1945-7111/ad7408
Junam Kwon and Kenji Amaya
In this study, a new framework integrates simulations and flow cell experimentation to quantitatively understand the mechanism of chemical treatment reactions. Using this framework, the mechanisms of etching reactions induced by weak and strong acids were specifically investigated. A flow cell system experiment was developed for the etching experiment. Two acids (HNO3 and HF) were used, along with HNO3 without electrolytes. Average flow velocities were measured, and the molar flux of Fe2+ ions was determined by sampling the solution passing through the flow cell and measuring the iron content by using inductively coupled plasma. A concentration field simulation of the etching reaction in the flow cell was conducted. The concentration field within the boundary layer was visualized to understand the mechanism of H+ ion supply to the metal surface. In the case of weak acid solutions, H+ ions are primarily supplied by dissociation. In contrast, they were supplied by diffusion in strong acid solutions. A boundary layer formed within 100 μm from the metal surface. The experimental and simulated molar flux of Fe2+ ions were compared. The molar flux attributed to weak acid etching was more than 10 times that attributed to strong acids. The reaction rate constant of the H+ reduction reaction was evaluated through a parameter study. The influence of spectator ions on the etching process was investigated. An experiment was conducted to compare the etching of iron plates using HNO3 solutions with different concentrations of spectator ion. The results confirmed that the higher the concentration of the spectator ion, the greater the etching amount. Numerical analysis revealed that the electric field in the electric migration term acts in a direction that impedes the movement of H+ ions to the metal surface. While it is already known that electric migration inhibits electrode reactions, this study enabled its quantitative visualization and evaluation.
{"title":"Framework Integrated with Flow Cell Experiments and Simulations for Understanding Etching in Chemical Conversion Treatments","authors":"Junam Kwon and Kenji Amaya","doi":"10.1149/1945-7111/ad7408","DOIUrl":"https://doi.org/10.1149/1945-7111/ad7408","url":null,"abstract":"In this study, a new framework integrates simulations and flow cell experimentation to quantitatively understand the mechanism of chemical treatment reactions. Using this framework, the mechanisms of etching reactions induced by weak and strong acids were specifically investigated. A flow cell system experiment was developed for the etching experiment. Two acids (HNO3 and HF) were used, along with HNO3 without electrolytes. Average flow velocities were measured, and the molar flux of Fe2+ ions was determined by sampling the solution passing through the flow cell and measuring the iron content by using inductively coupled plasma. A concentration field simulation of the etching reaction in the flow cell was conducted. The concentration field within the boundary layer was visualized to understand the mechanism of H+ ion supply to the metal surface. In the case of weak acid solutions, H+ ions are primarily supplied by dissociation. In contrast, they were supplied by diffusion in strong acid solutions. A boundary layer formed within 100 μm from the metal surface. The experimental and simulated molar flux of Fe2+ ions were compared. The molar flux attributed to weak acid etching was more than 10 times that attributed to strong acids. The reaction rate constant of the H+ reduction reaction was evaluated through a parameter study. The influence of spectator ions on the etching process was investigated. An experiment was conducted to compare the etching of iron plates using HNO3 solutions with different concentrations of spectator ion. The results confirmed that the higher the concentration of the spectator ion, the greater the etching amount. Numerical analysis revealed that the electric field in the electric migration term acts in a direction that impedes the movement of H+ ions to the metal surface. While it is already known that electric migration inhibits electrode reactions, this study enabled its quantitative visualization and evaluation.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-08DOI: 10.1149/1945-7111/ad7532
Mingran Yang, Yingchen Xu, Zhengcha Pang, Chenghan Yang, Jinqiang Huang, Min Zhu and Yiwei Zhang
In electrochemical reduction of carbon dioxide (CO2RR), the design of electrocatalysts with high efficiency and selectivity is very important and challenging. In this paper, a ternary composite consisting of ruthenium dioxide and bismuth metal porphyrin-based organic framework (Bi-TCPP MOF)-derived bismuth trioxide and C skeleton has been proposed (denoted as Bi2O3-RuO2@C). Nanoscale RuO2 and Bi2O3 particles are uniformly distributed on the C skeleton. The precursor bismuth metal porphyrin-based organic framework restricts the localized growth of Bi2O3 in the framework, while the unique, highly-conjugated system anchors the doped RuO2 particles, resulting in a uniform distribution of both active sites and hole-enrichment centers. Meanwhile, the Bi-TCPP MOF-derived carbon skeleton has good electrical conductivity, and the macroporous structure also facilitates the gas transport, which leads to the synthesis of Bi2O3-RuO2@C as an electrocatalyst for CO2RR and exhibits excellent catalytic performance and high selectivity for electrocatalytic carbon dioxide reduction to methane (CO2-CH4). The peak Faraday efficiency of Bi2O3-RuO2@C for catalyzing the reduction of CO2-CH4 can reach 66.95% when the doped RuO2 content is 20%. Importantly, this work opens up new horizons for metal ratio regulation in constructing efficient catalytic systems derived from MOFs.
{"title":"Bismuth Metal Porphyrin Framework Doped RuO2 Derived Bi2O3-RuO2@C Composites for Highly Selective CO2 Electroreduction","authors":"Mingran Yang, Yingchen Xu, Zhengcha Pang, Chenghan Yang, Jinqiang Huang, Min Zhu and Yiwei Zhang","doi":"10.1149/1945-7111/ad7532","DOIUrl":"https://doi.org/10.1149/1945-7111/ad7532","url":null,"abstract":"In electrochemical reduction of carbon dioxide (CO2RR), the design of electrocatalysts with high efficiency and selectivity is very important and challenging. In this paper, a ternary composite consisting of ruthenium dioxide and bismuth metal porphyrin-based organic framework (Bi-TCPP MOF)-derived bismuth trioxide and C skeleton has been proposed (denoted as Bi2O3-RuO2@C). Nanoscale RuO2 and Bi2O3 particles are uniformly distributed on the C skeleton. The precursor bismuth metal porphyrin-based organic framework restricts the localized growth of Bi2O3 in the framework, while the unique, highly-conjugated system anchors the doped RuO2 particles, resulting in a uniform distribution of both active sites and hole-enrichment centers. Meanwhile, the Bi-TCPP MOF-derived carbon skeleton has good electrical conductivity, and the macroporous structure also facilitates the gas transport, which leads to the synthesis of Bi2O3-RuO2@C as an electrocatalyst for CO2RR and exhibits excellent catalytic performance and high selectivity for electrocatalytic carbon dioxide reduction to methane (CO2-CH4). The peak Faraday efficiency of Bi2O3-RuO2@C for catalyzing the reduction of CO2-CH4 can reach 66.95% when the doped RuO2 content is 20%. Importantly, this work opens up new horizons for metal ratio regulation in constructing efficient catalytic systems derived from MOFs.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1149/1945-7111/ad7407
O. Horner, D. P. Wilkinson, E. L. Gyenge
Seawater electrolysis suffers from many issues that must be resolved before the technology can be scaled. The corrosive hypochlorite formation at the anode can damage the electrode and other electrolyzer components. Furthermore, hypochlorite is unstable and can decay, particularly when exposed to heat and metal ions, which could lead to erroneously high oxygen evolution reaction (OER) selectivity calculations in catalyst benchmarking experiments, resulting in poor catalyst and electrolyzer component selection. In this study, we used the rotating ring-disc electrode (RRDE) technique for the characterization of IrO2, NiO, Co3O4, RuO2, Pt/C, and PtRu electrocatalysts at near-neutral pH (8.4) in 0.5 M NaCl. The RRDE can overcome the challenge posed by thermocatalytic hypochlorite decay. IrO2 and PtRu were also studied over a range of chloride concentrations from 0.1 to 1 M. Our findings reveal that elevated temperatures (313 and 333 K) are conducive to higher OER selectivity, as the OER faradaic efficiency (FE) on IrO2 increased by 23% at 1.22 V vs SHE when the temperature was increased from 293 to 333 K. Increasing the chloride concentration from 0.1 to 1 M increased the OER current density by 40% and 200% on IrO2 and PtRu, respectively, indicating a synergistic relationship.
海水电解存在许多问题，必须先解决这些问题，才能扩大该技术的规模。阳极上形成的次氯酸盐具有腐蚀性，会损坏电极和其他电解槽部件。此外，次氯酸盐不稳定，特别是在受热和接触金属离子时会发生衰变，这可能导致催化剂基准实验中氧进化反应（OER）选择性计算错误，从而导致催化剂和电解槽组件选择不当。在本研究中，我们采用旋转环盘电极（RRDE）技术，在 0.5 M NaCl 溶液中以接近中性的 pH 值（8.4）表征了 IrO2、NiO、Co3O4、RuO2、Pt/C 和 PtRu 电催化剂。RRDE 可以克服次氯酸盐热催化衰变带来的挑战。我们的研究结果表明，温度升高（313 和 333 K）有利于提高 OER 的选择性，因为 IrO2 上的 OER 法拉第效率（FE）在 1.将氯化物浓度从 0.1 M 提高到 1 M，IrO2 和 PtRu 上的 OER 电流密度分别提高了 40% 和 200%，这表明两者之间存在协同关系。
{"title":"Selectivity Study of Direct Seawater Electrolyzer Anode Catalysts Using the Rotating Ring-Disc Electrode Method","authors":"O. Horner, D. P. Wilkinson, E. L. Gyenge","doi":"10.1149/1945-7111/ad7407","DOIUrl":"https://doi.org/10.1149/1945-7111/ad7407","url":null,"abstract":"Seawater electrolysis suffers from many issues that must be resolved before the technology can be scaled. The corrosive hypochlorite formation at the anode can damage the electrode and other electrolyzer components. Furthermore, hypochlorite is unstable and can decay, particularly when exposed to heat and metal ions, which could lead to erroneously high oxygen evolution reaction (OER) selectivity calculations in catalyst benchmarking experiments, resulting in poor catalyst and electrolyzer component selection. In this study, we used the rotating ring-disc electrode (RRDE) technique for the characterization of IrO<sub>2</sub>, NiO, Co<sub>3</sub>O<sub>4</sub>, RuO<sub>2</sub>, Pt/C, and PtRu electrocatalysts at near-neutral pH (8.4) in 0.5 M NaCl. The RRDE can overcome the challenge posed by thermocatalytic hypochlorite decay. IrO<sub>2</sub> and PtRu were also studied over a range of chloride concentrations from 0.1 to 1 M. Our findings reveal that elevated temperatures (313 and 333 K) are conducive to higher OER selectivity, as the OER faradaic efficiency (FE) on IrO<sub>2</sub> increased by 23% at 1.22 V vs SHE when the temperature was increased from 293 to 333 K. Increasing the chloride concentration from 0.1 to 1 M increased the OER current density by 40% and 200% on IrO<sub>2</sub> and PtRu, respectively, indicating a synergistic relationship.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1149/1945-7111/ad6e1f
Saheli Bhattacharjee, Sovandeb Sen, Susmita Kundu
Vanadium pentoxide (V2O5), associated with both cathodic and anodic coloration, is considered as one of the best electrochromic (EC) materials for energy-saving smart electronics. Here we present the fabrication and detailed mechanism analysis for improving the electrochromic properties of V2O5 incorporated in a reduced graphene oxide (rGO) matrix using a facile wet chemical method. The microstructural study disclosed the formation of prominent V2O5 nanorods embedded in the rGO matrix. The optimized electrochromic film resulted in coloration (tc) and bleaching time (tb) of ∼6.2 and ∼4.8 s, respectively, much faster than the color switching kinetics of the pristine V2O5 sample (tc ∼ 19.4 s, tb ∼ 15.3 s). The more dispersed structure also ensured an approximate 400% enhancement in the optical modulation of EC film and reflected a noticeable improvement in the coloration efficiency (∼347 cm2/C) of V2O5 film. Modification with rGO resulted in an outstanding improvement in the electrochemical redox stability of V2O5 up to 5000 CV cycles with minimum deterioration in the curve area. The formation of nanorod structure was the prime factor for better ion diffusion and thereby facilitating enhanced performance.
{"title":"Robust Dual-Color Electrochromism of Vanadium Oxide Nanorods Embedded on Reduced Graphene Oxide: Unraveling the Mechanism","authors":"Saheli Bhattacharjee, Sovandeb Sen, Susmita Kundu","doi":"10.1149/1945-7111/ad6e1f","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6e1f","url":null,"abstract":"Vanadium pentoxide (V<sub>2</sub>O<sub>5</sub>), associated with both cathodic and anodic coloration, is considered as one of the best electrochromic (EC) materials for energy-saving smart electronics. Here we present the fabrication and detailed mechanism analysis for improving the electrochromic properties of V<sub>2</sub>O<sub>5</sub> incorporated in a reduced graphene oxide (rGO) matrix using a facile wet chemical method. The microstructural study disclosed the formation of prominent V<sub>2</sub>O<sub>5</sub> nanorods embedded in the rGO matrix. The optimized electrochromic film resulted in coloration (t<sub>c</sub>) and bleaching time (t<sub>b</sub>) of ∼6.2 and ∼4.8 s, respectively, much faster than the color switching kinetics of the pristine V<sub>2</sub>O<sub>5</sub> sample (t<sub>c</sub> ∼ 19.4 s, t<sub>b</sub> ∼ 15.3 s). The more dispersed structure also ensured an approximate 400% enhancement in the optical modulation of EC film and reflected a noticeable improvement in the coloration efficiency (∼347 cm<sup>2</sup>/C) of V<sub>2</sub>O<sub>5</sub> film. Modification with rGO resulted in an outstanding improvement in the electrochemical redox stability of V<sub>2</sub>O<sub>5</sub> up to 5000 CV cycles with minimum deterioration in the curve area. The formation of nanorod structure was the prime factor for better ion diffusion and thereby facilitating enhanced performance.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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