Pub Date : 2024-11-17DOI: 10.1016/j.electacta.2024.145365
Alessandro Brega, Sylvain Brimaud
Herein, an electrochemical channel flow cell setup that allows for conducting electrochemical investigations up to 80°C and pressurized gases up to 3 bar is presented in details, including technical drawings and list of parts, in an attempt to facilitate the adoption of such setup by the community for electrochemical/electrocatalytic kinetic studies. The oxygen reduction reaction (ORR) on a commercial Pt/C catalyst, chosen as a model reaction, was investigated to demonstrate the reliability of the experimental setup, including the hydrodynamic properties, to provide hands on practical guidelines to carry out experiments, and, on the other hand, to illustrate the capabilities of this electrochemical setup for an assessment of basic quantities. Among the various quantities that have be determined experimentally for the ORR, a monotonic decay of the activation enthalpy and bell-shaped variation of the entropy of activation were resolved as the overpotential for the ORR increases. These fundamental thermodynamic/kinetic data are briefly discussed within the frame of the established reaction mechanism and can serve as a feed for the benchmarking of the outputs from theoretical/computational models. Furthermore, a remarkable agreement was obtained between the change in the activation free Gibbs energy determined for the ORR with the flow cell setup and the kinetic region of fuel cell polarization curve obtained with the same Pt/C catalyst embedded in the cathode of an a hydrogen proton exchange membrane fuel cell. This enables potentially a bridge of the environmental gap existing between model experiments conducted at active material level in contact with liquid electrolyte and experiments with porous gas diffusion electrode embedding the same active material that are employed in practical device.
{"title":"An open source electrochemical channel flow cell setup for kinetics studies. Application to investigations on oxygen electrocatalysis.","authors":"Alessandro Brega, Sylvain Brimaud","doi":"10.1016/j.electacta.2024.145365","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145365","url":null,"abstract":"Herein, an electrochemical channel flow cell setup that allows for conducting electrochemical investigations up to 80°C and pressurized gases up to 3 bar is presented in details, including technical drawings and list of parts, in an attempt to facilitate the adoption of such setup by the community for electrochemical/electrocatalytic kinetic studies. The oxygen reduction reaction (ORR) on a commercial Pt/C catalyst, chosen as a model reaction, was investigated to demonstrate the reliability of the experimental setup, including the hydrodynamic properties, to provide hands on practical guidelines to carry out experiments, and, on the other hand, to illustrate the capabilities of this electrochemical setup for an assessment of basic quantities. Among the various quantities that have be determined experimentally for the ORR, a monotonic decay of the activation enthalpy and bell-shaped variation of the entropy of activation were resolved as the overpotential for the ORR increases. These fundamental thermodynamic/kinetic data are briefly discussed within the frame of the established reaction mechanism and can serve as a feed for the benchmarking of the outputs from theoretical/computational models. Furthermore, a remarkable agreement was obtained between the change in the activation free Gibbs energy determined for the ORR with the flow cell setup and the kinetic region of fuel cell polarization curve obtained with the same Pt/C catalyst embedded in the cathode of an a hydrogen proton exchange membrane fuel cell. This enables potentially a bridge of the environmental gap existing between model experiments conducted at active material level in contact with liquid electrolyte and experiments with porous gas diffusion electrode embedding the same active material that are employed in practical device.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"32 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.electacta.2024.145344
Anis Allagui, Enrique H. Balaguera
Under a particular geometrical arrangements of impedances of the type resistors and capacitors for the modeling of a transmission line, the voltage and current along the line are known to follow the standard partial differential equation of diffusion. In this work we propose a generalization of this circuit network by considering the non-ideal fractional capacitive element, also known as constant phase element (CPE), as the energy storage component. The CPE’s impedance is given by <span><span><math><mrow is="true"><msub is="true"><mrow is="true"><mi is="true">Z</mi></mrow><mrow is="true"><mi is="true">c</mi></mrow></msub><mrow is="true"><mo is="true">(</mo><mi is="true">s</mi><mo is="true">)</mo></mrow><mo is="true" linebreak="goodbreak" linebreakstyle="after">=</mo><mn is="true">1</mn><mo is="true">/</mo><mrow is="true"><mo is="true">(</mo><msub is="true"><mrow is="true"><mi is="true">C</mi></mrow><mrow is="true"><mi is="true">α</mi></mrow></msub><msup is="true"><mrow is="true"><mi is="true">s</mi></mrow><mrow is="true"><mi is="true">α</mi></mrow></msup><mo is="true">)</mo></mrow></mrow></math></span><script type="math/mml"><math><mrow is="true"><msub is="true"><mrow is="true"><mi is="true">Z</mi></mrow><mrow is="true"><mi is="true">c</mi></mrow></msub><mrow is="true"><mo is="true">(</mo><mi is="true">s</mi><mo is="true">)</mo></mrow><mo linebreak="goodbreak" linebreakstyle="after" is="true">=</mo><mn is="true">1</mn><mo is="true">/</mo><mrow is="true"><mo is="true">(</mo><msub is="true"><mrow is="true"><mi is="true">C</mi></mrow><mrow is="true"><mi is="true">α</mi></mrow></msub><msup is="true"><mrow is="true"><mi is="true">s</mi></mrow><mrow is="true"><mi is="true">α</mi></mrow></msup><mo is="true">)</mo></mrow></mrow></math></script></span>, where <span><span><math><mrow is="true"><msub is="true"><mrow is="true"><mi is="true">C</mi></mrow><mrow is="true"><mi is="true">α</mi></mrow></msub><mo is="true" linebreak="goodbreak" linebreakstyle="after">></mo><mn is="true">0</mn></mrow></math></span><script type="math/mml"><math><mrow is="true"><msub is="true"><mrow is="true"><mi is="true">C</mi></mrow><mrow is="true"><mi is="true">α</mi></mrow></msub><mo linebreak="goodbreak" linebreakstyle="after" is="true">></mo><mn is="true">0</mn></mrow></math></script></span> and <span><span><math><mrow is="true"><mn is="true">0</mn><mo is="true" linebreak="goodbreak" linebreakstyle="after"><</mo><mi is="true">α</mi><mo is="true" linebreak="goodbreak" linebreakstyle="after">⩽</mo><mn is="true">1</mn></mrow></math></span><script type="math/mml"><math><mrow is="true"><mn is="true">0</mn><mo linebreak="goodbreak" linebreakstyle="after" is="true"><</mo><mi is="true">α</mi><mo linebreak="goodbreak" linebreakstyle="after" is="true">⩽</mo><mn is="true">1</mn></mrow></math></script></span>, and offers an extra degree of freedom compared to the ideal capacitor of impedance <span><span><math><mrow is="true"><mi is="true">Z</mi><mo is="true" linebreak="goodbrea
{"title":"On the semi-infinite distributed resistor-constant phase element transmission line","authors":"Anis Allagui, Enrique H. Balaguera","doi":"10.1016/j.electacta.2024.145344","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145344","url":null,"abstract":"Under a particular geometrical arrangements of impedances of the type resistors and capacitors for the modeling of a transmission line, the voltage and current along the line are known to follow the standard partial differential equation of diffusion. In this work we propose a generalization of this circuit network by considering the non-ideal fractional capacitive element, also known as constant phase element (CPE), as the energy storage component. The CPE’s impedance is given by <span><span><math><mrow is=\"true\"><msub is=\"true\"><mrow is=\"true\"><mi is=\"true\">Z</mi></mrow><mrow is=\"true\"><mi is=\"true\">c</mi></mrow></msub><mrow is=\"true\"><mo is=\"true\">(</mo><mi is=\"true\">s</mi><mo is=\"true\">)</mo></mrow><mo is=\"true\" linebreak=\"goodbreak\" linebreakstyle=\"after\">=</mo><mn is=\"true\">1</mn><mo is=\"true\">/</mo><mrow is=\"true\"><mo is=\"true\">(</mo><msub is=\"true\"><mrow is=\"true\"><mi is=\"true\">C</mi></mrow><mrow is=\"true\"><mi is=\"true\">α</mi></mrow></msub><msup is=\"true\"><mrow is=\"true\"><mi is=\"true\">s</mi></mrow><mrow is=\"true\"><mi is=\"true\">α</mi></mrow></msup><mo is=\"true\">)</mo></mrow></mrow></math></span><script type=\"math/mml\"><math><mrow is=\"true\"><msub is=\"true\"><mrow is=\"true\"><mi is=\"true\">Z</mi></mrow><mrow is=\"true\"><mi is=\"true\">c</mi></mrow></msub><mrow is=\"true\"><mo is=\"true\">(</mo><mi is=\"true\">s</mi><mo is=\"true\">)</mo></mrow><mo linebreak=\"goodbreak\" linebreakstyle=\"after\" is=\"true\">=</mo><mn is=\"true\">1</mn><mo is=\"true\">/</mo><mrow is=\"true\"><mo is=\"true\">(</mo><msub is=\"true\"><mrow is=\"true\"><mi is=\"true\">C</mi></mrow><mrow is=\"true\"><mi is=\"true\">α</mi></mrow></msub><msup is=\"true\"><mrow is=\"true\"><mi is=\"true\">s</mi></mrow><mrow is=\"true\"><mi is=\"true\">α</mi></mrow></msup><mo is=\"true\">)</mo></mrow></mrow></math></script></span>, where <span><span><math><mrow is=\"true\"><msub is=\"true\"><mrow is=\"true\"><mi is=\"true\">C</mi></mrow><mrow is=\"true\"><mi is=\"true\">α</mi></mrow></msub><mo is=\"true\" linebreak=\"goodbreak\" linebreakstyle=\"after\">></mo><mn is=\"true\">0</mn></mrow></math></span><script type=\"math/mml\"><math><mrow is=\"true\"><msub is=\"true\"><mrow is=\"true\"><mi is=\"true\">C</mi></mrow><mrow is=\"true\"><mi is=\"true\">α</mi></mrow></msub><mo linebreak=\"goodbreak\" linebreakstyle=\"after\" is=\"true\">></mo><mn is=\"true\">0</mn></mrow></math></script></span> and <span><span><math><mrow is=\"true\"><mn is=\"true\">0</mn><mo is=\"true\" linebreak=\"goodbreak\" linebreakstyle=\"after\"><</mo><mi is=\"true\">α</mi><mo is=\"true\" linebreak=\"goodbreak\" linebreakstyle=\"after\">⩽</mo><mn is=\"true\">1</mn></mrow></math></span><script type=\"math/mml\"><math><mrow is=\"true\"><mn is=\"true\">0</mn><mo linebreak=\"goodbreak\" linebreakstyle=\"after\" is=\"true\"><</mo><mi is=\"true\">α</mi><mo linebreak=\"goodbreak\" linebreakstyle=\"after\" is=\"true\">⩽</mo><mn is=\"true\">1</mn></mrow></math></script></span>, and offers an extra degree of freedom compared to the ideal capacitor of impedance <span><span><math><mrow is=\"true\"><mi is=\"true\">Z</mi><mo is=\"true\" linebreak=\"goodbrea","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"8 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.electacta.2024.145358
Abdul Majeed, Nicholas Hemmerling, Bastian J.M. Etzold
Critical investigation of methods used to screen the catalytic activity of different electrocatalysts is crucial for the development of water electrolysis technology. One of such protocols to justify the catalytic activity trend among different catalysts involves determining their electrochemically active surface area (ECSA) which is usually estimated from non-Faradic double layered capacitance (Cdl) of the catalyst material. Furthermore, catalytic current normalized with ECSA is frequently used to gain insight into the intrinsic activity of a catalyst. Since not all the metallic catalysts are highly stable under the electrolysis conditions, it is highly important, though rarely explored, to investigate whether or not the adsorption/desorption of leached/dissolved multivalent metal ions influences the measurement of non-Faradic Cdl. Here, we explore the possible influence of Mo leached from NiMo alloy on the measured Cdl of NiMo. Using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), Cdl of NiMo alloy was measured before and after carrying out long term (chronopotentiometric and CV cycling) hydrogen evolution reaction (HER) in alkaline conditions. After extended HER testing, we observe a notable rise (∼22% averaging all our experiments) in the Cdl of NiMo alloy when measured with traditional methods. Interestingly, only 8% of this increase can be attributed to an expansion in surface area. We hypothesize that the majority of the increase in Cdl stems from the higher amount of charges stored through leached multivalent ions, which accumulate within surface cavities.
{"title":"Pitfall on the interpretation of double layer capacitance increase after accelerated stress test of hydrogen evolution reaction on NiMo catalysts","authors":"Abdul Majeed, Nicholas Hemmerling, Bastian J.M. Etzold","doi":"10.1016/j.electacta.2024.145358","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145358","url":null,"abstract":"Critical investigation of methods used to screen the catalytic activity of different electrocatalysts is crucial for the development of water electrolysis technology. One of such protocols to justify the catalytic activity trend among different catalysts involves determining their electrochemically active surface area (ECSA) which is usually estimated from non-Faradic double layered capacitance (C<sub>dl</sub>) of the catalyst material. Furthermore, catalytic current normalized with ECSA is frequently used to gain insight into the intrinsic activity of a catalyst. Since not all the metallic catalysts are highly stable under the electrolysis conditions, it is highly important, though rarely explored, to investigate whether or not the adsorption/desorption of leached/dissolved multivalent metal ions influences the measurement of non-Faradic C<sub>dl</sub>. Here, we explore the possible influence of Mo leached from NiMo alloy on the measured C<sub>dl</sub> of NiMo. Using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), C<sub>dl</sub> of NiMo alloy was measured before and after carrying out long term (chronopotentiometric and CV cycling) hydrogen evolution reaction (HER) in alkaline conditions. After extended HER testing, we observe a notable rise (∼22% averaging all our experiments) in the C<sub>dl</sub> of NiMo alloy when measured with traditional methods. Interestingly, only 8% of this increase can be attributed to an expansion in surface area. We hypothesize that the majority of the increase in C<sub>dl</sub> stems from the higher amount of charges stored through leached multivalent ions, which accumulate within surface cavities.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.electacta.2024.145367
Weliton Silva Fonseca, Thibault Rafaïdeen, Hamza Kahri, Têko W. Napporn, Christophe Coutanceau
NiAu/C nanomaterials are synthesised using a wet chemistry method with targeted Au atomic ratios of 10%, 20% and 30%. Physicochemical characterisations indicate that the materials have mean compositions close to the nominal ones but ca. 20 at% Au richer in average than expected (Au ratios of 13.6 at%, 23.1 at% and 35.9 at%, respectively). The NiAu/C materials are composed of Au-rich spherical-like Janus particles of several tenths nm and of a phase of very small Ni-rich nanoparticles and Ni(OH2) clusters. The electrochemical measurements in a 0.1 M NaOH/0.1 M glucose electrolyte indicate that the NiAu20/C catalyst is the most active for the glucose oxidation reaction, leading to a mass activity at +0.6 V vs RHE more than 1.5 times higher than that with a pure Au/C catalyst, although the Au content is almost 5 times lower. The chronoamperometry measurements for 900 s at +0.6 V vs RHE confirm the activity gain with the NiAu20/C catalyst. The electrolysis measurement at a cell voltage of +Z+0.6 V for 6 hours shows that the NiAu20/C catalyst is selective towards the production of gluconic acid, with a faradaic efficiency higher than 100%, indicating the occurrence of a 1-electron reaction with anodic hydrogen coproduction. At +0.8 V, the faradaic efficiency is lower than 100 %, indicating the formation of other products than gluconic acid, but at a very low extent (not detectable by HPLC) guarantying a very high selectivity towards gluconic acid.
采用湿化学方法合成了 NiAu/C 纳米材料，目标金原子比分别为 10%、20% 和 30%。理化特性表明，这些材料的平均成分接近标称成分，但平均金含量比预期高出约 20 个百分点（金比率分别为 13.6 个百分点、23.1 个百分点和 35.9 个百分点）。NiAu/C 材料由万分之几纳米的富金球状 Janus 颗粒和极小的富镍纳米颗粒及 Ni（OH2）团簇组成。在 0.1 M NaOH/0.1 M 葡萄糖电解液中进行的电化学测量表明，NiAu20/C 催化剂在葡萄糖氧化反应中最为活跃，在 +0.6 V 对比 RHE 时的质量活性比纯 Au/C 催化剂高出 1.5 倍以上，尽管 Au 的含量几乎低了 5 倍。在 +0.6 V 对 RHE 条件下进行的 900 秒计时器测量证实了 NiAu20/C 催化剂的活性提高。在 +Z+0.6 V 的电池电压下进行 6 小时的电解测量表明，NiAu20/C 催化剂对葡萄糖酸的生产具有选择性，其远红外效率高于 100%，这表明发生了阳极氢气共生的 1 电子反应。在 +0.8 V 电压下，法拉第效率低于 100%，这表明除葡萄糖酸外，还生成了其他产物，但生成量极低（HPLC 检测不到），保证了对葡萄糖酸的极高选择性。
{"title":"Glucose electrooxidation on carbon supported NiAu electrocatalysts","authors":"Weliton Silva Fonseca, Thibault Rafaïdeen, Hamza Kahri, Têko W. Napporn, Christophe Coutanceau","doi":"10.1016/j.electacta.2024.145367","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145367","url":null,"abstract":"NiAu/C nanomaterials are synthesised using a wet chemistry method with targeted Au atomic ratios of 10%, 20% and 30%. Physicochemical characterisations indicate that the materials have mean compositions close to the nominal ones but ca. 20 at% Au richer in average than expected (Au ratios of 13.6 at%, 23.1 at% and 35.9 at%, respectively). The NiAu/C materials are composed of Au-rich spherical-like Janus particles of several tenths nm and of a phase of very small Ni-rich nanoparticles and Ni(OH<sub>2</sub>) clusters. The electrochemical measurements in a 0.1 M NaOH/0.1 M glucose electrolyte indicate that the NiAu20/C catalyst is the most active for the glucose oxidation reaction, leading to a mass activity at +0.6 V vs RHE more than 1.5 times higher than that with a pure Au/C catalyst, although the Au content is almost 5 times lower. The chronoamperometry measurements for 900 s at +0.6 V vs RHE confirm the activity gain with the NiAu20/C catalyst. The electrolysis measurement at a cell voltage of +Z+0.6 V for 6 hours shows that the NiAu20/C catalyst is selective towards the production of gluconic acid, with a faradaic efficiency higher than 100%, indicating the occurrence of a 1-electron reaction with anodic hydrogen coproduction. At +0.8 V, the faradaic efficiency is lower than 100 %, indicating the formation of other products than gluconic acid, but at a very low extent (not detectable by HPLC) guarantying a very high selectivity towards gluconic acid.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"50 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.electacta.2024.145362
Anne A. Macedo, Dilton M. Pimentel, Amanda N. de Souza, Higor M. Mundim, Luciano M. Lião, Lívia M.F. Costa, Rodrigo Moreira Verly, Wallans T.P. dos Santos
Minoxidil (MN) is a vasodilator used to treat hair loss and severe hypertension. However, its illegal use in cosmetics and pharmaceutical formulations has been reported in several countries. An efficient method for MN detection is of great interest for forensic and pharmaceutical applications. Electrochemical sensors have been reported as an interesting alternative for MN detection in various samples. However, a more in-depth study of the redox processes and a more selective electrochemical detection for MN are still required. In this context, we present, for the first time, the use of nuclear magnetic resonance and Fourier transform infrared spectroscopy analyses for understanding the electrochemical behaviour of MN after electrolysis procedures on a boron-doped diamond electrode (BDDE). Using these combined techniques, we have proposed and confirmed an electrochemical mechanism for all redox processes of MN on a BDDE, where in phosphate buffer (pH 6.0) two oxidation processes at +0.72 V and +0.97 V vs (Ag/AgCl/ sat. KCl) are presented. The last generated product by MN oxidation is reduced on the BDDE surface at -0.01 V with a quasi-reversible redox process. The use of this redox process is the strategy for a selective and sensitive detection of MN on the BDDE. This innovative approach was successfully applied to determine MN in adulterated cosmetics and pharmaceutical formulations, showing a low limit of detection (5.7 µmol. L-1) and high stability of electrochemical responses (RSD < 1.5 %, n = 6) using the same BDDE. Therefore, the proposed method provides a simple, fast and selective method for the identification and quantification of MN in pharmaceutical and forensic samples.
{"title":"Voltammetric detection with a comprehensive electrochemistry study of minoxidil using nuclear magnetic resonance and infrared analyses: Applications in the forensic and pharmaceutical fields.","authors":"Anne A. Macedo, Dilton M. Pimentel, Amanda N. de Souza, Higor M. Mundim, Luciano M. Lião, Lívia M.F. Costa, Rodrigo Moreira Verly, Wallans T.P. dos Santos","doi":"10.1016/j.electacta.2024.145362","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145362","url":null,"abstract":"Minoxidil (MN) is a vasodilator used to treat hair loss and severe hypertension. However, its illegal use in cosmetics and pharmaceutical formulations has been reported in several countries. An efficient method for MN detection is of great interest for forensic and pharmaceutical applications. Electrochemical sensors have been reported as an interesting alternative for MN detection in various samples. However, a more in-depth study of the redox processes and a more selective electrochemical detection for MN are still required. In this context, we present, for the first time, the use of nuclear magnetic resonance and Fourier transform infrared spectroscopy analyses for understanding the electrochemical behaviour of MN after electrolysis procedures on a boron-doped diamond electrode (BDDE). Using these combined techniques, we have proposed and confirmed an electrochemical mechanism for all redox processes of MN on a BDDE, where in phosphate buffer (pH 6.0) two oxidation processes at +0.72 V and +0.97 V vs (Ag/AgCl/ sat. KCl) are presented. The last generated product by MN oxidation is reduced on the BDDE surface at -0.01 V with a quasi-reversible redox process. The use of this redox process is the strategy for a selective and sensitive detection of MN on the BDDE. This innovative approach was successfully applied to determine MN in adulterated cosmetics and pharmaceutical formulations, showing a low limit of detection (5.7 µmol. L<sup>-1</sup>) and high stability of electrochemical responses (RSD < 1.5 %, n = 6) using the same BDDE. Therefore, the proposed method provides a simple, fast and selective method for the identification and quantification of MN in pharmaceutical and forensic samples.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.electacta.2024.145363
Rok Šmerc, Damijan Miklavčič, Samo Mahnič-Kalamiza
Electroporation often leads to electrochemical reactions at the electrode-electrolytic solution interface, particularly when using monophasic pulses of considerable duration (typically on the order of several microseconds or longer) that cause not only capacitive charging of the double-layer, but also faradaic charge transfer between the electrodes and the solution. Applications, where the electrochemical changes are to be either avoided or actively exploited to benefit the treatment, range from gene electrotransfer to electrolytic ablation of tissue. Through numerical modelling and experimental validation, our study explores the extent of pH changes induced by faradaic currents in a surrogate tissue. A mechanistic multiphysics model of pH changes was developed based on first principles, incorporating hydrolysis reactions at the anode and cathode, and the Nernst-Planck model of ion transport. The model was validated using agarose gel tissue phantoms designed to simulate unbuffered and buffered (mimicking in vivo tissue buffering capacity) conditions. An imaging system with pH-sensitive dyes was developed and used to visualise and quantify pH front formation and migration. The model predictions qualitatively aligned well with experimental data, differentiating pH front behaviour between unbuffered and buffered media. However, the quantitative accuracy in predicting the temporal and spatial evolution of the pH fronts can be further improved. Experimental observations emphasise the need for more advanced models. Nevertheless, the developed model provides a sound theoretical foundation for predicting pH changes due to high-voltage electric pulse delivery, such as encountered in electroporation-based treatments and therapies.
{"title":"AN EXPERIMENTALLY VALIDATED NUMERICAL MODEL OF PH CHANGES IN SURROGATE TISSUE INDUCED BY ELECTROPORATION PULSES","authors":"Rok Šmerc, Damijan Miklavčič, Samo Mahnič-Kalamiza","doi":"10.1016/j.electacta.2024.145363","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145363","url":null,"abstract":"Electroporation often leads to electrochemical reactions at the electrode-electrolytic solution interface, particularly when using monophasic pulses of considerable duration (typically on the order of several microseconds or longer) that cause not only capacitive charging of the double-layer, but also faradaic charge transfer between the electrodes and the solution. Applications, where the electrochemical changes are to be either avoided or actively exploited to benefit the treatment, range from gene electrotransfer to electrolytic ablation of tissue. Through numerical modelling and experimental validation, our study explores the extent of pH changes induced by faradaic currents in a surrogate tissue. A mechanistic multiphysics model of pH changes was developed based on first principles, incorporating hydrolysis reactions at the anode and cathode, and the Nernst-Planck model of ion transport. The model was validated using agarose gel tissue phantoms designed to simulate unbuffered and buffered (mimicking <em>in vivo</em> tissue buffering capacity) conditions. An imaging system with pH-sensitive dyes was developed and used to visualise and quantify pH front formation and migration. The model predictions qualitatively aligned well with experimental data, differentiating pH front behaviour between unbuffered and buffered media. However, the quantitative accuracy in predicting the temporal and spatial evolution of the pH fronts can be further improved. Experimental observations emphasise the need for more advanced models. Nevertheless, the developed model provides a sound theoretical foundation for predicting pH changes due to high-voltage electric pulse delivery, such as encountered in electroporation-based treatments and therapies.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"247 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.electacta.2024.145340
Fiyanshu Kaka, Kalyan Sundar Krishna Chivukula
The emergence of all-solid-state batteries (ASSBs) introduces a paradigm shift in energy storage technology, offering enhanced safety compared to conventional liquid-based metal-ion batteries. Significant effort is directed toward optimizing the solid-electrolyte blend composition to enhance the battery’s electrochemical performance. Despite some promising results, a lack of guidelines persists, particularly for optimizing multicomponent solid electrolytes given their large parameter window. This study aims to address this challenge by implementing a unified diffuse-interface approach to model and simulate the solid electrolyte morphologies and their corresponding electrochemical performance when incorporated in a battery. The electrolyte microstructures are simulated using the Cahn-Hilliard formulation while a diffuse-interface framework formulated in terms of electrochemical potential is utilized for exploring Li-ion transport across the battery. It is found that, while the variegated microstructures arising from various solid electrolyte blend compositions influence the power density of the battery, the electronic band structure of the blend phases is an important consideration. The proposed model is versatile and can be adapted for various battery technologies beyond ASSBs. This expands its potential impact and could lead to innovations in energy storage technology.
{"title":"Deciphering the influence of multi-component blends and their electronic band structure on the performance of All-Solid-State Batteries","authors":"Fiyanshu Kaka, Kalyan Sundar Krishna Chivukula","doi":"10.1016/j.electacta.2024.145340","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145340","url":null,"abstract":"The emergence of all-solid-state batteries (ASSBs) introduces a paradigm shift in energy storage technology, offering enhanced safety compared to conventional liquid-based metal-ion batteries. Significant effort is directed toward optimizing the solid-electrolyte blend composition to enhance the battery’s electrochemical performance. Despite some promising results, a lack of guidelines persists, particularly for optimizing multicomponent solid electrolytes given their large parameter window. This study aims to address this challenge by implementing a unified diffuse-interface approach to model and simulate the solid electrolyte morphologies and their corresponding electrochemical performance when incorporated in a battery. The electrolyte microstructures are simulated using the Cahn-Hilliard formulation while a diffuse-interface framework formulated in terms of electrochemical potential is utilized for exploring Li-ion transport across the battery. It is found that, while the variegated microstructures arising from various solid electrolyte blend compositions influence the power density of the battery, the electronic band structure of the blend phases is an important consideration. The proposed model is versatile and can be adapted for various battery technologies beyond ASSBs. This expands its potential impact and could lead to innovations in energy storage technology.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"64 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the past decades, the proton exchange membrane fuel cell (PEMFC) components, cell/stack designs and system architecture have been significantly improved. However, despite great initial performance, PEMFC systems still suffer technological limitations, such as their initial cost, partly due to the use of expensive Pt-based electrocatalyst, which prevents widespread industrial deployment. Lowering the cathode catalyst loading while keeping high (and durable) catalytic activity has been intensively studied. In this work, low-loaded catalyst layers (20 and 100 µgPt cmgeo−2) are tested in PEMFC differential single-cell (DC) under high reactant stoichiometry to characterize their intrinsic electrochemical properties under various ideal and well-controlled operating conditions of cell temperature (T) and relative humidity (RH). Particularly, the change of the membrane hydration state, via the ohmic resistance measurement, and the Pt-oxides surface coverage are investigated to gather information on the physico-chemical and electrochemical mechanisms involved in the cathode active layer, and the typical performance hysteresis observed during dynamic operation such as polarization curves. These specific electrochemical measurements further enable to build a dataset, that can be used to improve PEMFC models taking into account the complex ORR mechanism, and the role of the Pt oxides in catalyst layer transient operation and degradation.
{"title":"Low-Loaded Catalyst Layers For Proton Exchange Membrane Fuel Cell Dynamic Operation Part 1: Experimental Study","authors":"Florent Vandenberghe, Fabrice Micoud, Pascal Schott, Arnaud Morin, Clémence Lafforgue, Marian Chatenet","doi":"10.1016/j.electacta.2024.145364","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145364","url":null,"abstract":"In the past decades, the proton exchange membrane fuel cell (PEMFC) components, cell/stack designs and system architecture have been significantly improved. However, despite great initial performance, PEMFC systems still suffer technological limitations, such as their initial cost, partly due to the use of expensive Pt-based electrocatalyst, which prevents widespread industrial deployment. Lowering the cathode catalyst loading while keeping high (and durable) catalytic activity has been intensively studied. In this work, low-loaded catalyst layers (20 and 100 µg<sub>Pt</sub> cm<sub>geo</sub><sup>−2</sup>) are tested in PEMFC differential single-cell (DC) under high reactant stoichiometry to characterize their intrinsic electrochemical properties under various ideal and well-controlled operating conditions of cell temperature (<em>T</em>) and relative humidity (<em>RH</em>). Particularly, the change of the membrane hydration state, via the ohmic resistance measurement, and the Pt-oxides surface coverage are investigated to gather information on the physico-chemical and electrochemical mechanisms involved in the cathode active layer, and the typical performance hysteresis observed during dynamic operation such as polarization curves. These specific electrochemical measurements further enable to build a dataset, that can be used to improve PEMFC models taking into account the complex ORR mechanism, and the role of the Pt oxides in catalyst layer transient operation and degradation.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to their high energy density and cost-effectiveness, rechargeable zinc-air batteries (ZABs) are increasingly recognized for their potential as long-duration energy storage solutions. A crucial component for maximizing their efficiency is the membrane separator, which must exhibit high hydroxide-ion conductivity and long-term stability. This study introduces an innovative hybrid composite separator, created by embedding thin-layered molybdenum disulfide (MoS2), known for its intrinsic negative charge, into a polycationic quaternized PVA-chitosan (CS) matrix. Polyvinyl alcohol (PVA) is functionalized with quaternary ammonium (QA) groups before being combined with CS and MoS2, using a solvent blending technique. The separator's three-dimensional structure and morphology is analyzed via synchrotron radiation X-ray tomographic microscopy (SR-XTM). Results demonstrate that the ZAB equipped with a quaternized PVA/CS/0.5 wt.% MoS2 composite separator achieved a high conductivity of 87.3 mS cm-1 and exceptional stability, enduring over 465 cycles. This performance is attributed to the synergistic interaction between the quaternized PVA-CS matrix and the MoS2 surface, forming robust polymer complexes through electrostatic interactions. These findings suggest that the developed separators hold significant promise for advanced ZAB applications.
{"title":"Enhanced Long-Term Stability of Zinc-Air Batteries Using a Quaternized PVA-Chitosan Composite Separator with Thin-Layered MoS2","authors":"Nuttapon Suppanucroa, Warunyoo Yoopensuk, Jirapha Pimoei, Wacharapisuth Thanapong-a-morn, Wathanyu Kao-Ian, Phakkhananan Pakawanit, Falko Mahlendorf, Soorathep Kheawhom, Anongnat Somwangthanaroj","doi":"10.1016/j.electacta.2024.145361","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145361","url":null,"abstract":"Due to their high energy density and cost-effectiveness, rechargeable zinc-air batteries (ZABs) are increasingly recognized for their potential as long-duration energy storage solutions. A crucial component for maximizing their efficiency is the membrane separator, which must exhibit high hydroxide-ion conductivity and long-term stability. This study introduces an innovative hybrid composite separator, created by embedding thin-layered molybdenum disulfide (MoS<sub>2</sub>), known for its intrinsic negative charge, into a polycationic quaternized PVA-chitosan (CS) matrix. Polyvinyl alcohol (PVA) is functionalized with quaternary ammonium (QA) groups before being combined with CS and MoS<sub>2</sub>, using a solvent blending technique. The separator's three-dimensional structure and morphology is analyzed via synchrotron radiation X-ray tomographic microscopy (SR-XTM). Results demonstrate that the ZAB equipped with a quaternized PVA/CS/0.5 wt.% MoS<sub>2</sub> composite separator achieved a high conductivity of 87.3 mS cm<sup>-1</sup> and exceptional stability, enduring over 465 cycles. This performance is attributed to the synergistic interaction between the quaternized PVA-CS matrix and the MoS<sub>2</sub> surface, forming robust polymer complexes through electrostatic interactions. These findings suggest that the developed separators hold significant promise for advanced ZAB applications.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"13 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-15DOI: 10.1016/j.electacta.2024.145333
Lei Zhang, Bing Sun, Qinghua Liu, Lin Song, Teibang Zhang, Xiaobo Duan
It has come to our attention that we misspelled the name of the corresponding author,
我们注意到，我们拼错了通讯作者的名字、
{"title":"Corrigendum to the author information of “Solvent-derived inorganic F and N-rich solid electrolyte interface for stable lithium metal batteries” [Electrochimica Acta, Volume 503, 2024, 144909]","authors":"Lei Zhang, Bing Sun, Qinghua Liu, Lin Song, Teibang Zhang, Xiaobo Duan","doi":"10.1016/j.electacta.2024.145333","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145333","url":null,"abstract":"It has come to our attention that we misspelled the name of the corresponding author,","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"18 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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