Pub Date : 2024-07-12DOI: 10.1149/1945-7111/ad6295
L. Dai, Tengteng Zhao, Chaoyu Wang, W. Meng, Yongguang Liu, Yuehuan Li, Ling Wang
NO2 is an important pollutant of automobile engines and industrial fuels, making it important to quantitatively monitor and control. An amperometric-type NO2 gas sensor was fabricated using yttria-stabilized zirconia (YSZ) electrolyte with a bi-layered structure and La0.7Sr0.3MnO3-δ-xNiO (LSMO-xNiO, x=0-0.75) composite sensing electrode (SE) prepared by impregnation method in combination with self-demixing. The samples were characterized using SEM, XRD, and XPS, and their performance as sensors was tested. LSMO-xNiO composite SE particles were formed by de-mixing in the process of treating the precursor at high temperatures and are uniformly dispersed in the YSZ porous backbone. With the increase of NiO content, the SE particles become significantly large. At 450-600°C, the response currents at a fixed potential have a linear relationship with the NO2 concentrations at 25-700 ppm. Combining stability and sensitivity, the voltage was fixed to -0.25V. The introduction of NiO into the LSMO sensing electrode effectively improves the performance of the sensor. The sensor based on LSMO-0.5NiO has the highest sensitivity (0.0405 µA/ppm) at 550°C. Simultaneously, the sensor exhibits good anti-interference ability for CH4, CO2, O2, and NO, but has obvious cross-sensitivity to H2 and NH3. In addition, the response current of the sensor change with the increase of RH.
{"title":"An Amperometric Type NO2 Sensor Utilizing La0.7Sr0.3MnO3-δ-NiO Composite Sensing Electrode","authors":"L. Dai, Tengteng Zhao, Chaoyu Wang, W. Meng, Yongguang Liu, Yuehuan Li, Ling Wang","doi":"10.1149/1945-7111/ad6295","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6295","url":null,"abstract":"\u0000 NO2 is an important pollutant of automobile engines and industrial fuels, making it important to quantitatively monitor and control. An amperometric-type NO2 gas sensor was fabricated using yttria-stabilized zirconia (YSZ) electrolyte with a bi-layered structure and La0.7Sr0.3MnO3-δ-xNiO (LSMO-xNiO, x=0-0.75) composite sensing electrode (SE) prepared by impregnation method in combination with self-demixing. The samples were characterized using SEM, XRD, and XPS, and their performance as sensors was tested. LSMO-xNiO composite SE particles were formed by de-mixing in the process of treating the precursor at high temperatures and are uniformly dispersed in the YSZ porous backbone. With the increase of NiO content, the SE particles become significantly large. At 450-600°C, the response currents at a fixed potential have a linear relationship with the NO2 concentrations at 25-700 ppm. Combining stability and sensitivity, the voltage was fixed to -0.25V. The introduction of NiO into the LSMO sensing electrode effectively improves the performance of the sensor. The sensor based on LSMO-0.5NiO has the highest sensitivity (0.0405 µA/ppm) at 550°C. Simultaneously, the sensor exhibits good anti-interference ability for CH4, CO2, O2, and NO, but has obvious cross-sensitivity to H2 and NH3. In addition, the response current of the sensor change with the increase of RH.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141652975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-12DOI: 10.1149/1945-7111/ad6298
Deepika Choudhary, Ritu Bala, Rajnish Dhiman
The high ionic conductivity, lower interfacial contact resistance, enhanced safety, non-toxicity, and biodegradability bring the gel polymer electrolytes (GPEs) as a prospective electrolyte for applications in high-energy density flexible Zn-air batteries (ZABs). The present study comprehensively optimizes the procedures to obtain carboxymethyl cellulose (CMC)– polyvinyl alcohol (PVA) composite-based GPEs holding a maximum KOH amount in the polymer matrix. Optimization of the GPE has been performed and demonstrated by an in-house-developed rechargeable ZAB cells using MnO2-based air cathode and Zn anode. The optimization parameters include the ratio of PVA:CMC, concentration of PVA-CMC in DI water, and thickness of the gel polymer electrolyte. Results show that a 4 mm thick GPE prepared from a polymer membrane synthesized using PVA:CMC ratio of 5:2 at a concentration of 0.063 g/ml in DI water displayed the highest 6M KOH uptake, least charge transfer resistance of the device, higher discharge plateau, and 5-6 times more cycling compared to GPE made of PVA only. The "as-synthesized GPE" demonstrates high stability of GPE over 100 hours for a Zn-air battery device. The findings of this work shall speed up the development of Zn air batteries for applications as energy storage systems.
{"title":"Carboxymethyl Cellulose – Polyvinyl Alcohol Composite-Based Gel Polymer Electrolyte for Rechargeable Zn-Air Batteries","authors":"Deepika Choudhary, Ritu Bala, Rajnish Dhiman","doi":"10.1149/1945-7111/ad6298","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6298","url":null,"abstract":"\u0000 The high ionic conductivity, lower interfacial contact resistance, enhanced safety, non-toxicity, and biodegradability bring the gel polymer electrolytes (GPEs) as a prospective electrolyte for applications in high-energy density flexible Zn-air batteries (ZABs). The present study comprehensively optimizes the procedures to obtain carboxymethyl cellulose (CMC)– polyvinyl alcohol (PVA) composite-based GPEs holding a maximum KOH amount in the polymer matrix. Optimization of the GPE has been performed and demonstrated by an in-house-developed rechargeable ZAB cells using MnO2-based air cathode and Zn anode. The optimization parameters include the ratio of PVA:CMC, concentration of PVA-CMC in DI water, and thickness of the gel polymer electrolyte. Results show that a 4 mm thick GPE prepared from a polymer membrane synthesized using PVA:CMC ratio of 5:2 at a concentration of 0.063 g/ml in DI water displayed the highest 6M KOH uptake, least charge transfer resistance of the device, higher discharge plateau, and 5-6 times more cycling compared to GPE made of PVA only. The \"as-synthesized GPE\" demonstrates high stability of GPE over 100 hours for a Zn-air battery device. The findings of this work shall speed up the development of Zn air batteries for applications as energy storage systems.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141654898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-11DOI: 10.1149/1945-7111/ad6211
Mohammad Fathi Tovini, Ana Marija Damjanovic, Hany A. El-Sayed, Benjamin Strehle, József Spéder, A. Ghielmi, H. Gasteiger
IrO2 has been widely used as the anode co-catalyst for mitigating cell voltage reversal damages in proton exchange membrane fuel cells (PEMFCs). However, under the PEMFC anode operation conditions, conventionally prepared IrO2 catalysts are reduced by H2, forming metallic Ir on their surface, which is prone to dissolution during start-up/shut-down (SUSD) cycles. The dissolved Irn+ ions can permeate through the membrane to the cathode electrode, poisoning the oxygen reduction reaction (ORR) activity of the Pt/C cathode catalyst. In this study, we introduce an unprecedented approach to synthesize IrO2 catalysts (irr-IrO2) which are not reduced in the PEMFC anode environment at 80°C over extended time. Their preparation is based on an industrially scalable procedure, consisting of a high-temperature (650-1000°C) heat treatment step, a subsequent ball milling step, and a final post-annealing step, thereby attaining catalysts with specific surface areas of ~ 25 m2 g-1. The high reduction resistance of the irr-IrO2 catalysts, attributed to their highly ordered crystalline structure compared to that of typically synthesized IrO2 catalysts, is reflected by the observation that SUSD cycling of MEAs with the irr-IrO2 as anode co-catalysts does not result in iridium dissolution and the associated iridium poisoning of the Pt/C cathode catalyst.
{"title":"Irreducible IrO2 Anode Co-Catalysts for PEM Fuel Cell Voltage Reversal Mitigation and Their Stability Under Start-Up/Shut-Down Conditions","authors":"Mohammad Fathi Tovini, Ana Marija Damjanovic, Hany A. El-Sayed, Benjamin Strehle, József Spéder, A. Ghielmi, H. Gasteiger","doi":"10.1149/1945-7111/ad6211","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6211","url":null,"abstract":"\u0000 IrO2 has been widely used as the anode co-catalyst for mitigating cell voltage reversal damages in proton exchange membrane fuel cells (PEMFCs). However, under the PEMFC anode operation conditions, conventionally prepared IrO2 catalysts are reduced by H2, forming metallic Ir on their surface, which is prone to dissolution during start-up/shut-down (SUSD) cycles. The dissolved Irn+ ions can permeate through the membrane to the cathode electrode, poisoning the oxygen reduction reaction (ORR) activity of the Pt/C cathode catalyst. In this study, we introduce an unprecedented approach to synthesize IrO2 catalysts (irr-IrO2) which are not reduced in the PEMFC anode environment at 80°C over extended time. Their preparation is based on an industrially scalable procedure, consisting of a high-temperature (650-1000°C) heat treatment step, a subsequent ball milling step, and a final post-annealing step, thereby attaining catalysts with specific surface areas of ~ 25 m2 g-1. The high reduction resistance of the irr-IrO2 catalysts, attributed to their highly ordered crystalline structure compared to that of typically synthesized IrO2 catalysts, is reflected by the observation that SUSD cycling of MEAs with the irr-IrO2 as anode co-catalysts does not result in iridium dissolution and the associated iridium poisoning of the Pt/C cathode catalyst.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141657058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-11DOI: 10.1149/1945-7111/ad6214
Adrija Rukmini, R. Ghotkar, Derall M. Riley, Jiashen Tian, R. Milcarek
The degradation of the solid-oxide fuel cell (SOFC) nickel-yttria stabilized zirconia anode under decamethyltetrasiloxane (L4) contamination was examined with experiments and modeling. A model was developed for the polarization losses based on the charge transfer coefficient, α, and diffusion layer thickness, δ, and fitted to the experimental data to understand how the siloxane degrades the SOFC performance with time. The results of the model indicate that the total polarization losses increase approximately 44% over the course of the 180 min experiment at 350 mA/cm2. Activation losses dominate the polarization losses initially but decrease in their total contribution while concentration losses increase. Scanning electron microscopy with wavelength dispersive X-ray spectroscopy elemental mapping indicates that silicon deposition is highest at the outer edge of the anode and forms a barrier layer to fuel diffusion, increasing concentration losses. When the model was applied to other previous D4 and L4 siloxane experiments conducted over a period of 40 hours, similar trends in polarization losses were observed. Polarization losses increase more rapidly with D4 compared to L4 siloxane contamination, with concentration losses increasing the fastest with both types of siloxane.
{"title":"Modeling and Analysis of Polarization Losses in Solid Oxide Fuel Cells with Siloxane Contamination","authors":"Adrija Rukmini, R. Ghotkar, Derall M. Riley, Jiashen Tian, R. Milcarek","doi":"10.1149/1945-7111/ad6214","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6214","url":null,"abstract":"\u0000 The degradation of the solid-oxide fuel cell (SOFC) nickel-yttria stabilized zirconia anode under decamethyltetrasiloxane (L4) contamination was examined with experiments and modeling. A model was developed for the polarization losses based on the charge transfer coefficient, α, and diffusion layer thickness, δ, and fitted to the experimental data to understand how the siloxane degrades the SOFC performance with time. The results of the model indicate that the total polarization losses increase approximately 44% over the course of the 180 min experiment at 350 mA/cm2. Activation losses dominate the polarization losses initially but decrease in their total contribution while concentration losses increase. Scanning electron microscopy with wavelength dispersive X-ray spectroscopy elemental mapping indicates that silicon deposition is highest at the outer edge of the anode and forms a barrier layer to fuel diffusion, increasing concentration losses. When the model was applied to other previous D4 and L4 siloxane experiments conducted over a period of 40 hours, similar trends in polarization losses were observed. Polarization losses increase more rapidly with D4 compared to L4 siloxane contamination, with concentration losses increasing the fastest with both types of siloxane.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141658090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-11DOI: 10.1149/1945-7111/ad6215
D. Mazur, O. Pariiska, Y. Kurys', Vyacheslav Koshechko, V. Pokhodenko
Transition metal phosphides (TMPs) and their composites are promising non-platinum electrocatalysts for hydrogen evolution (HER), oxygen evolution (OER), and oxygen reduction (ORR) reactions. But traditional methods to obtain these electrocatalysts are usually multi-step and include the participation of hazardous phosphorus compounds during phosphidation. Here, the possibility of using a polyaniline doped with phosphoric acid (PANI∙H3PO4) – as a source of C, N and P simultaneously - to obtain composites based on N,P-doped carbon and nano- and/or submicron TMP particles as HER, OER and ORR electrocatalysts is demonstrated. The pyrolysis of PANI∙H3PO4 together with Co, Ni, Mo, or Fe salt allows the formation of such composite electrocatalysts by the carbon thermal reduction route. Regardless of the pH of the electrolyte, the MoP-based electrocatalyst is characterized in HER by the smallest Tafel slope and overpotential of hydrogen evolution and also exhibits high stability during long-term operation. At the same time, other composites are multifunctional electrocatalysts possessing activity not only in HER, but also in OER and ORR. The proposed approach can be a starting point for a simple, universal in choice of d-metal, and environmentally attractive preparation of multifunctional TMP-based electrocatalysts with further improvement of their performance.
过渡金属磷化物（TMPs）及其复合材料是氢进化（HER）、氧进化（OER）和氧还原（ORR）反应中很有前途的非铂电催化剂。但是，获得这些电催化剂的传统方法通常需要经过多个步骤，而且在磷化过程中还需要有害磷化合物的参与。在此，我们展示了使用掺杂磷酸的聚苯胺（PANI∙H3PO4）同时作为 C、N 和 P 的来源，获得基于 N、P 掺杂碳和纳米及/或亚微米 TMP 粒子的复合材料作为 HER、OER 和 ORR 电催化剂的可能性。将 PANI∙H3PO4 与 Co、Ni、Mo 或 Fe 盐一起热解，可通过碳热还原途径形成这种复合电催化剂。无论电解质的 pH 值如何，基于 MoP 的电催化剂在 HER 中的特点是氢演化的塔菲尔斜率和过电位最小，并且在长期运行中表现出很高的稳定性。与此同时，其他复合材料是多功能电催化剂，不仅在 HER 中具有活性，而且在 OER 和 ORR 中也具有活性。所提出的方法可以作为一个起点，用于制备基于 TMP 的多功能电催化剂，并进一步提高其性能。
{"title":"Facile Carbothermal Synthesis of Metal Phosphides-Based Multifunctional Electrocatalysts via Polyaniline Doped with Phosphoric Acid","authors":"D. Mazur, O. Pariiska, Y. Kurys', Vyacheslav Koshechko, V. Pokhodenko","doi":"10.1149/1945-7111/ad6215","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6215","url":null,"abstract":"\u0000 Transition metal phosphides (TMPs) and their composites are promising non-platinum electrocatalysts for hydrogen evolution (HER), oxygen evolution (OER), and oxygen reduction (ORR) reactions. But traditional methods to obtain these electrocatalysts are usually multi-step and include the participation of hazardous phosphorus compounds during phosphidation. Here, the possibility of using a polyaniline doped with phosphoric acid (PANI∙H3PO4) – as a source of C, N and P simultaneously - to obtain composites based on N,P-doped carbon and nano- and/or submicron TMP particles as HER, OER and ORR electrocatalysts is demonstrated. The pyrolysis of PANI∙H3PO4 together with Co, Ni, Mo, or Fe salt allows the formation of such composite electrocatalysts by the carbon thermal reduction route. Regardless of the pH of the electrolyte, the MoP-based electrocatalyst is characterized in HER by the smallest Tafel slope and overpotential of hydrogen evolution and also exhibits high stability during long-term operation. At the same time, other composites are multifunctional electrocatalysts possessing activity not only in HER, but also in OER and ORR. The proposed approach can be a starting point for a simple, universal in choice of d-metal, and environmentally attractive preparation of multifunctional TMP-based electrocatalysts with further improvement of their performance.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141658142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-11DOI: 10.1149/1945-7111/ad6212
Steffen Brundiers, P. Trinke, B. Bensmann, R. Hanke‐Rauschenbach
Platinum-based recombination interlayers (ILs) are a promising approach to mitigate hydrogen and oxygen crossover during proton exchange membrane (PEM) electrolysis. Until now, there are only experimental investigations on this topic, which demonstrate the integral behavior of a PEM electrolysis cell with an IL but do not resolve local effects. This paper addresses these issues by proposing a first model-based approach to investigate the effects of ILs in PEM water electrolysis cells. We focus on local concentration profiles, crossover fluxes, Faraday efficiency, operational limits, and heat generation. The experimentally validated model shows that the IL substantially affects the local concentrations of dissolved hydrogen and oxygen. Depending on pressure condition and current density, different species can limit the recombination reaction in the IL. The results show that ILs can extend the operational window even for high cathode pressures and thin membranes if enough oxygen is present in the IL to recombine the permeating hydrogen. Additionally, we demonstrate that ILs do not influence the Faraday efficiency of the cell due to two counteracting loss mechanisms. Finally, our simulations indicate that the heat generation from the recombination reaction in the IL has almost no effect on the temperature distribution in the cell.
铂基重组中间膜（IL）是质子交换膜（PEM）电解过程中减缓氢氧交叉的一种有效方法。迄今为止，关于这一主题的研究只有实验研究，这些研究展示了带有IL的PEM电解池的整体行为，但没有解决局部效应问题。本文针对这些问题，首次提出了一种基于模型的方法，用于研究 PEM 水电解槽中 IL 的影响。我们的重点是局部浓度曲线、交叉通量、法拉第效率、运行限制和发热。实验验证的模型表明，IL 对溶解氢和溶解氧的局部浓度有很大影响。根据压力条件和电流密度的不同，不同的物种会限制电离层中的重组反应。结果表明，如果 IL 中存在足够的氧气来重组渗透氢，那么即使在阴极压力较高和膜较薄的情况下，IL 也能延长运行窗口。此外，我们还证明，由于存在两种相互抵消的损耗机制，IL 不会影响电池的法拉第效率。最后，我们的模拟表明，IL 中重组反应产生的热量对电池中的温度分布几乎没有影响。
{"title":"Model-Based Investigation of Recombination Interlayers in PEM Water Electrolysis: Concentration Profiles, Efficiency, and Operational Limits","authors":"Steffen Brundiers, P. Trinke, B. Bensmann, R. Hanke‐Rauschenbach","doi":"10.1149/1945-7111/ad6212","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6212","url":null,"abstract":"\u0000 Platinum-based recombination interlayers (ILs) are a promising approach to mitigate hydrogen and oxygen crossover during proton exchange membrane (PEM) electrolysis. Until now, there are only experimental investigations on this topic, which demonstrate the integral behavior of a PEM electrolysis cell with an IL but do not resolve local effects. This paper addresses these issues by proposing a first model-based approach to investigate the effects of ILs in PEM water electrolysis cells. We focus on local concentration profiles, crossover fluxes, Faraday efficiency, operational limits, and heat generation. The experimentally validated model shows that the IL substantially affects the local concentrations of dissolved hydrogen and oxygen. Depending on pressure condition and current density, different species can limit the recombination reaction in the IL. The results show that ILs can extend the operational window even for high cathode pressures and thin membranes if enough oxygen is present in the IL to recombine the permeating hydrogen. Additionally, we demonstrate that ILs do not influence the Faraday efficiency of the cell due to two counteracting loss mechanisms. Finally, our simulations indicate that the heat generation from the recombination reaction in the IL has almost no effect on the temperature distribution in the cell.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141656286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-11DOI: 10.1149/1945-7111/ad6213
Maurice Friedrichs-Schucht, F. Hasché, M. Oezaslan
Water management is critical for high performance of polymer electrolyte membrane water electrolysis (PEMWE). In this work, we investigated the water crossover for 5 cm2 PEMWE single cell by varying the temperature (40 – 80 °C), current density (0 – 2 A cm-2 geo), cathode pressure (ambient, 310 kPagauge,inlet), and nitrogen purge rate (50, 100 nccm). Using an advanced gravimetric method, water crossover to the cathode could be established very accurately and also corrected by the water vapor fraction. We pointed out that the cathode exhaust gas is saturated with water vapor, either from diffusion or by proton drag at low or high current densities, respectively. Very importantly, water crossover at high current density is controlled by proton drag and are used to extract the temperature-dependent proton drag coefficient at 1 A cm-2geo. Our results reveal that the proton drag coefficient increases from 2.5 ± 0.2 at 40 °C to 3.2 ± 0.2 at 80 °C (+28 %). Altogether, we have developed a sophisticated gravimetric method to accurately determine water crossover under PEMWE operatingconditions and proposed a model of the temperature-dependent proton drag coefficient. Unravelling the proton drag and diffusion is very important for modeling of water transport in PEMWE.
水管理对聚合物电解质膜电解水（PEMWE）的高性能至关重要。在这项工作中，我们通过改变温度（40 - 80 °C）、电流密度（0 - 2 A cm-2 geo）、阴极压力（环境压力、310 kPagauge 入口压力）和氮气吹扫率（50、100 nccm），研究了 5 cm2 PEMWE 单电池的水交叉情况。利用先进的重力测量法，可以非常准确地确定阴极的水交叉情况，并根据水蒸气分数进行校正。我们指出，在电流密度较低或较高时，阴极废气中的水蒸气会因扩散或质子阻力而饱和。非常重要的是，高电流密度下的水交叉是由质子阻力控制的，我们用它来提取 1 A cm-2geo 时与温度相关的质子阻力系数。结果显示，质子阻力系数从 40 °C 时的 2.5 ± 0.2 增加到 80 °C 时的 3.2 ± 0.2（+28%）。总之，我们开发了一种复杂的重力测量方法，用于准确测定 PEMWE 工作条件下的水交叉，并提出了一个质子阻力系数随温度变化的模型。揭示质子阻力和扩散对 PEMWE 中的水传输建模非常重要。
{"title":"Water Crossover in Proton Exchange Membrane Water Electrolysis","authors":"Maurice Friedrichs-Schucht, F. Hasché, M. Oezaslan","doi":"10.1149/1945-7111/ad6213","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6213","url":null,"abstract":"\u0000 Water management is critical for high performance of polymer electrolyte membrane water electrolysis (PEMWE). In this work, we investigated the water crossover for 5 cm2 PEMWE single cell by varying the temperature (40 – 80 °C), current density (0 – 2 A cm-2\u0000 geo), cathode pressure (ambient, 310 kPagauge,inlet), and nitrogen purge rate (50, 100 nccm). Using an advanced gravimetric method, water crossover to the cathode could be established very accurately and also corrected by the water vapor fraction. We pointed out that the cathode exhaust gas is saturated with water vapor, either from diffusion or by proton drag at low or high current densities, respectively. Very importantly, water crossover at high current density is controlled by proton drag and are used to extract the temperature-dependent proton drag coefficient at 1 A cm-2geo. Our results reveal that the proton drag coefficient increases from 2.5 ± 0.2 at 40 °C to 3.2 ± 0.2 at 80 °C (+28 %). Altogether, we have developed a sophisticated gravimetric method to accurately determine water crossover under PEMWE operatingconditions and proposed a model of the temperature-dependent proton drag coefficient. Unravelling the proton drag and diffusion is very important for modeling of water transport in PEMWE.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141658949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-10DOI: 10.1149/1945-7111/ad6191
A. Nosal-Wiercińska, M. Martyna, Sultan Yagmur-Kabas
Using voltammetric and impedance methods, the effects of mixed adsorption layers ACT-CTAB and ACT-SDS on the kinetics and mechanism of In(III) ions electroreduction were investigated. Acetazolamide (ACT) was shown to catalyse the course of the electrode reaction (according to the cap-pair rule). The multi-step nature of the In(III) ions electroreduction process in each of the systems studied in the chemical step of formation of the active In(III) - ACT complexes in the adsorption layer playing an important role is demonstrated. The presence of the cationic surfactant CTAB increases the dynamics of acceleration of the In(III) ion electroreduction process by ACT, while the presence of the anionic surfactant SDS inhibits this reaction.
{"title":"Electrochemical Measurements of the In(III) Ions Electroreduction; the Influence of Mixed Adsorption Layers ACT-CTAB and ACT-SDS","authors":"A. Nosal-Wiercińska, M. Martyna, Sultan Yagmur-Kabas","doi":"10.1149/1945-7111/ad6191","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6191","url":null,"abstract":"\u0000 Using voltammetric and impedance methods, the effects of mixed adsorption layers ACT-CTAB and ACT-SDS on the kinetics and mechanism of In(III) ions electroreduction were investigated. Acetazolamide (ACT) was shown to catalyse the course of the electrode reaction (according to the cap-pair rule). The multi-step nature of the In(III) ions electroreduction process in each of the systems studied in the chemical step of formation of the active In(III) - ACT complexes in the adsorption layer playing an important role is demonstrated. The presence of the cationic surfactant CTAB increases the dynamics of acceleration of the In(III) ion electroreduction process by ACT, while the presence of the anionic surfactant SDS inhibits this reaction.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141659032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-10DOI: 10.1149/1945-7111/ad6192
Nawid Ahmad Akhtar, E. Gengec, M. Kobya
Wastewater from a small animal slaughterhouse (SWW) was treated by a two-step process: coagulation/flocculation (CF) followed by continuous flow electrooxidation (CFEO). Initially, a coagulant dose of 0.8 kg/m3 in the CF process, using FeCl3 at pH 8.5, achieved 52% COD and 63% turbidity removal (effluent: 2000 mg/L and 65.2 NTU). Alum, (optimum pH = 6.5), yielded 50% COD and 55% turbidity removal (effluent of 2100 mg/L and 78.5 NTU). Subsequently, when employing the CFEO process following the CF process with FeCl3, the study achieved highly efficient results. Specifically, under optimum conditions (residence time in the CFEO reactor, τ = 240 min, wastewater feed rate to the reactor = 15 mL/min, and current density = 300 A/m2), the COD and turbidity removal efficiencies reached 99.60% (resulting in an effluent of 8 mg/L) and 99.9% (resulting in an effluent of <0.10 NTU), respectively. In conclusion, the CF + CFEO consecutive treatment process demonstrated remarkable treatment efficiencies, with COD and turbidity removal rates of 99.9% and 99.9%, respectively. Moreover, the total operating cost of this treatment process was found to be 3.60 US $/m3.
{"title":"Treatment of Slaughterhouse Plant Wastewater by Sequential Chemical Coagulation-Continuous Flow Electrooxidation Process","authors":"Nawid Ahmad Akhtar, E. Gengec, M. Kobya","doi":"10.1149/1945-7111/ad6192","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6192","url":null,"abstract":"\u0000 Wastewater from a small animal slaughterhouse (SWW) was treated by a two-step process: coagulation/flocculation (CF) followed by continuous flow electrooxidation (CFEO). Initially, a coagulant dose of 0.8 kg/m3 in the CF process, using FeCl3 at pH 8.5, achieved 52% COD and 63% turbidity removal (effluent: 2000 mg/L and 65.2 NTU). Alum, (optimum pH = 6.5), yielded 50% COD and 55% turbidity removal (effluent of 2100 mg/L and 78.5 NTU). Subsequently, when employing the CFEO process following the CF process with FeCl3, the study achieved highly efficient results. Specifically, under optimum conditions (residence time in the CFEO reactor, τ = 240 min, wastewater feed rate to the reactor = 15 mL/min, and current density = 300 A/m2), the COD and turbidity removal efficiencies reached 99.60% (resulting in an effluent of 8 mg/L) and 99.9% (resulting in an effluent of <0.10 NTU), respectively. In conclusion, the CF + CFEO consecutive treatment process demonstrated remarkable treatment efficiencies, with COD and turbidity removal rates of 99.9% and 99.9%, respectively. Moreover, the total operating cost of this treatment process was found to be 3.60 US $/m3.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141659329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.1149/1945-7111/ad60f8
Qasim Z. Adesope, Mohammad Z. Altafi, Stella Z. Amagbor, Kabirat Z. Balogun, Manan Guragain, Alankar Kafle, V. Mesilov, Francis D’Souza, Tom Cundari, Jeffry Kelber
The electrochemical reduction of nitrate to ammonia is of interest as an energy/environmentally friendly source of ammonia for agriculture and energy applications and as a route toward groundwater purification. We report in situ photoemission data, electrochemical results, and density functional theory calculations that demonstrate vanadium oxide – prepared by ambient exposure of V metal, with a distribution of surface V3+ and V4+ oxidation states – specifically adsorbs and reduces nitrate to ammonia at pH 3.2 at cathodic potentials. Negligible cathodic activity in the absence of NO3- indicates high selectivity with respect to non-nitrate reduction processes. In situ photoemission data indicate that nitrate adsorption and reduction to adsorbed NO2 is a key step in the reduction process. NO3RR activity is also observed at pH 7, albeit at a much slower rate. The results indicate that intermediate (non-d0) oxidation states are important for both molecular nitrogen and nitrate reduction to ammonia.
{"title":"Electrocatalytic Reduction of Nitrate to Ammonia at Oxidized Vanadium Surfaces with V(3+) and V(4+) Oxidation States","authors":"Qasim Z. Adesope, Mohammad Z. Altafi, Stella Z. Amagbor, Kabirat Z. Balogun, Manan Guragain, Alankar Kafle, V. Mesilov, Francis D’Souza, Tom Cundari, Jeffry Kelber","doi":"10.1149/1945-7111/ad60f8","DOIUrl":"https://doi.org/10.1149/1945-7111/ad60f8","url":null,"abstract":"\u0000 The electrochemical reduction of nitrate to ammonia is of interest as an energy/environmentally friendly source of ammonia for agriculture and energy applications and as a route toward groundwater purification. We report in situ photoemission data, electrochemical results, and density functional theory calculations that demonstrate vanadium oxide – prepared by ambient exposure of V metal, with a distribution of surface V3+ and V4+ oxidation states – specifically adsorbs and reduces nitrate to ammonia at pH 3.2 at cathodic potentials. Negligible cathodic activity in the absence of NO3- indicates high selectivity with respect to non-nitrate reduction processes. In situ photoemission data indicate that nitrate adsorption and reduction to adsorbed NO2 is a key step in the reduction process. NO3RR activity is also observed at pH 7, albeit at a much slower rate. The results indicate that intermediate (non-d0) oxidation states are important for both molecular nitrogen and nitrate reduction to ammonia.","PeriodicalId":509718,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141664196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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