Pub Date : 2023-08-28DOI: 10.1149/ma2023-01512836mtgabs
Rong-Jun Xie
Luminescent materials play an important roles in lighting, display, plant growth, anti-counterfeit, medical and bio-technologies. The search for luminescent materials with desired properties never stops, but relies mostly on the trial-and-error approach, which is time-consuming and labor-intensive. Several methods have been proposed to accelerate the discovery of new luminescent materials, among them the data-driven one attracts much attention. In this presentation, two types of luminescent materials for different applications will be reported. Firstly, we build an emission-prediction model based on machine learning, and using this model found five Eu2+-doped nitride phosphors with highly efficient near-infrared (NIR) emissions. Secondly, we propose selection rules to discover laser phosphors and mechanoluminescent materials based on the structure-property relations, respectively. The applications of these phosphors in NIR detectors, laser lighting and stress mapping will also demonstrated.
{"title":"(Digital Presentation) Data-Driven Discovery of Luminescent Materials","authors":"Rong-Jun Xie","doi":"10.1149/ma2023-01512836mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01512836mtgabs","url":null,"abstract":"Luminescent materials play an important roles in lighting, display, plant growth, anti-counterfeit, medical and bio-technologies. The search for luminescent materials with desired properties never stops, but relies mostly on the trial-and-error approach, which is time-consuming and labor-intensive. Several methods have been proposed to accelerate the discovery of new luminescent materials, among them the data-driven one attracts much attention. In this presentation, two types of luminescent materials for different applications will be reported. Firstly, we build an emission-prediction model based on machine learning, and using this model found five Eu2+-doped nitride phosphors with highly efficient near-infrared (NIR) emissions. Secondly, we propose selection rules to discover laser phosphors and mechanoluminescent materials based on the structure-property relations, respectively. The applications of these phosphors in NIR detectors, laser lighting and stress mapping will also demonstrated.","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088847","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 : 2023-08-28DOI: 10.1149/ma2023-0154194mtgabs
Seungsoo Jang, Kyung Taek Bae, Dongyeon Kim, Hyeongmin Yu, Seeun Oh, Ha-Ni Im, Kang Taek Lee
The 3D reconstruction based on tomography technology enables quantitative and qualitative microstructural analysis of complex multiphase oxide structures. This powerful approach is widely investigated in diverse areas, in particular, gaining more importance in solid oxide electrochemical cells (SOCs) fields. SOCs are promising energy conversion devices with high efficiency, however, they have complex and porous/dense multilayered microstructures, which are closely related to the electrochemical reaction in the electrodes, thus, one of the major factors determining overall output performance of SOCs. Therefore, it is necessary to quantify the microstructural parameters of the cell. A focused ion beam-scanning electron microscope (FIB-SEM) dual beam system is one well-established method to obtain tomographic images to reconstruct 3D microstructures. It has an appropriate scale of tenth of nm to μm-level with high spatial resolution to represent the microstructural characteristics of the SOC electrodes. This presentation is intended to introduce our progress on 3D reconstruction techniques to quantitatively analyse SOCs, obtaining microstructural features such as particle size, connectivity, tortuosity, contact area, and triple phase boundary density. These in-depth analyses are helpful in extensively understanding electrochemical behavior in SOC electrodes.
{"title":"Microstructural Analysis of Solid Oxide Electrochemical Cells via 3D Reconstruction Using a FIB-SEM Dual Beam System","authors":"Seungsoo Jang, Kyung Taek Bae, Dongyeon Kim, Hyeongmin Yu, Seeun Oh, Ha-Ni Im, Kang Taek Lee","doi":"10.1149/ma2023-0154194mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-0154194mtgabs","url":null,"abstract":"The 3D reconstruction based on tomography technology enables quantitative and qualitative microstructural analysis of complex multiphase oxide structures. This powerful approach is widely investigated in diverse areas, in particular, gaining more importance in solid oxide electrochemical cells (SOCs) fields. SOCs are promising energy conversion devices with high efficiency, however, they have complex and porous/dense multilayered microstructures, which are closely related to the electrochemical reaction in the electrodes, thus, one of the major factors determining overall output performance of SOCs. Therefore, it is necessary to quantify the microstructural parameters of the cell. A focused ion beam-scanning electron microscope (FIB-SEM) dual beam system is one well-established method to obtain tomographic images to reconstruct 3D microstructures. It has an appropriate scale of tenth of nm to μm-level with high spatial resolution to represent the microstructural characteristics of the SOC electrodes. This presentation is intended to introduce our progress on 3D reconstruction techniques to quantitatively analyse SOCs, obtaining microstructural features such as particle size, connectivity, tortuosity, contact area, and triple phase boundary density. These in-depth analyses are helpful in extensively understanding electrochemical behavior in SOC electrodes.","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088881","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 : 2023-08-28DOI: 10.1149/ma2023-01442407mtgabs
Beum Geun Seo, Jongseon Park, beom Joon Kim, Gwon Deok Han, kang Hee Park, Heedeung Park, Joon Hyung Shim
Hetero-structured catalysts have recently attracted considerable interest from researchers in various fields, including electronics, sensing, energy, and photocatalysis. Treated water contains many harmful microorganisms and organic contaminants, which can be effectively removed through an advanced photocatalytic oxidation process. Photocatalysts with wide band gaps, such as semiconductor oxides like titanium dioxide (TiO 2 ) and zinc oxide (ZnO), are typically utilized to decompose these organic pollutants. These generate a charge when exposed to UV-A light irradiation and produce oxidation radicals that cause the decomposition of the organic matter present in water. Metals such as Pd, Ag, Au, Cu, and Ni are being studied as photocatalysts. Semiconducting oxides and metals with appropriate band gaps and Fermi levels can effectively capture the charge generated by the oxide owing to the Moss–Burstein effect. These reactions can enhance the photocatalytic effect by hindering the recombination of the generated holes and electrons, thereby increasing the probability of charge survival. In this study, the performance of zinc oxide nanowires (ZnO NWs) decorated with Pd nanoparticles was evaluated as photocatalysts for sustainable water treatment. To maximize the number of active sites on the surface of the ZnO nanowires, Pd nanoparticles were uniformly deposited via atomic layer deposition (ALD). In ALD, a very thin film that can be deposited in one cycle is created with less than one atomic layer owing to the precursor oxidation reaction. Additionally, the ALD process provides all the surfaces with sufficient time and chemical sources to react, resulting in a uniform amount of deposited material. This unique technology is suitable for the large-area deposition of atomic-level thickness surface materials. Therefore, ALD was used to deposit Pd onto the catalyst surface. The ZnO nanowires were initially fabricated in the form of seeds by ALD and grown via a hydrothermal method. Subsequently, ALD Pd nanoparticles with an average particle size of 3.75 nm were deposited on the enlarged ZnO nanowires. The prepared hetero-structured ALD Pd-deposited ZnO nanowires were analyzed using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and valence band X-ray photoelectron spectroscopy. A new Fermi level of the Pd-ZnO hetero-structure was formed, which was lower than the conduction band energy level of ZnO. The new Fermi level suppresses the recombination of the conduction band and valence band electron holes under UV-A irradiation. The enhanced charge separation enhances the photocatalytic activity. In addition, compared to ZnO NWs, ALD Pd-deposited ZnO NWs produced higher amounts of reactive oxygen species and improved the decomposition rate of organic pollutants in water. To evaluate the performance of the prepared photocatalyst, the decomposition rates of 4-chlorophenol (4-CP), 4-chlorobenzoic acid, and furfuryl alcohol were m
{"title":"Hetero-Structured Palladium-Coated Zinc Oxide Photocatalysts for Sustainable Water Treatment","authors":"Beum Geun Seo, Jongseon Park, beom Joon Kim, Gwon Deok Han, kang Hee Park, Heedeung Park, Joon Hyung Shim","doi":"10.1149/ma2023-01442407mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01442407mtgabs","url":null,"abstract":"Hetero-structured catalysts have recently attracted considerable interest from researchers in various fields, including electronics, sensing, energy, and photocatalysis. Treated water contains many harmful microorganisms and organic contaminants, which can be effectively removed through an advanced photocatalytic oxidation process. Photocatalysts with wide band gaps, such as semiconductor oxides like titanium dioxide (TiO 2 ) and zinc oxide (ZnO), are typically utilized to decompose these organic pollutants. These generate a charge when exposed to UV-A light irradiation and produce oxidation radicals that cause the decomposition of the organic matter present in water. Metals such as Pd, Ag, Au, Cu, and Ni are being studied as photocatalysts. Semiconducting oxides and metals with appropriate band gaps and Fermi levels can effectively capture the charge generated by the oxide owing to the Moss–Burstein effect. These reactions can enhance the photocatalytic effect by hindering the recombination of the generated holes and electrons, thereby increasing the probability of charge survival. In this study, the performance of zinc oxide nanowires (ZnO NWs) decorated with Pd nanoparticles was evaluated as photocatalysts for sustainable water treatment. To maximize the number of active sites on the surface of the ZnO nanowires, Pd nanoparticles were uniformly deposited via atomic layer deposition (ALD). In ALD, a very thin film that can be deposited in one cycle is created with less than one atomic layer owing to the precursor oxidation reaction. Additionally, the ALD process provides all the surfaces with sufficient time and chemical sources to react, resulting in a uniform amount of deposited material. This unique technology is suitable for the large-area deposition of atomic-level thickness surface materials. Therefore, ALD was used to deposit Pd onto the catalyst surface. The ZnO nanowires were initially fabricated in the form of seeds by ALD and grown via a hydrothermal method. Subsequently, ALD Pd nanoparticles with an average particle size of 3.75 nm were deposited on the enlarged ZnO nanowires. The prepared hetero-structured ALD Pd-deposited ZnO nanowires were analyzed using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and valence band X-ray photoelectron spectroscopy. A new Fermi level of the Pd-ZnO hetero-structure was formed, which was lower than the conduction band energy level of ZnO. The new Fermi level suppresses the recombination of the conduction band and valence band electron holes under UV-A irradiation. The enhanced charge separation enhances the photocatalytic activity. In addition, compared to ZnO NWs, ALD Pd-deposited ZnO NWs produced higher amounts of reactive oxygen species and improved the decomposition rate of organic pollutants in water. To evaluate the performance of the prepared photocatalyst, the decomposition rates of 4-chlorophenol (4-CP), 4-chlorobenzoic acid, and furfuryl alcohol were m","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088890","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 : 2023-08-28DOI: 10.1149/ma2023-01372193mtgabs
Lily Shiau, Harry A. Atwater
Harnessing solar energy to drive photocatalytic carbon dioxide reduction reactions (CO 2 RR) provides an appealing pathway to generate hydrocarbon and oxygenated fuels without an external power source. Zinc telluride (ZnTe) is a II-VI semiconductor which has been identified as a promising photocathode material due to its suitable band gap alignments to CO 2 reduction reaction potentials, chemical stability, and strong p-type character. Using molecular beam epitaxy (MBE), single crystal and epitaxial layers are synthesized to gain a deeper understanding of fundamental charge transport and reactivity mechanisms between the single crystal ZnTe thin film and the CO 2 -saturated electrolyte. These findings are of fundamental interest and are also critical to the design of efficient tandem solar fuels generators for unassisted photoelectrochemical CO 2 R. Epitaxy allows for highly controlled doping of the thin films over a large range of carrier concentrations. This work focuses largely on the synthesis and characterization of nitrogen doped p-type ZnTe via MBE. Films grown in the temperature range of 340–360ºC on GaAs of (100) orientation with a 200 nm undoped ZnTe buffer layer and a 100 nm doped ZnTe layer have been characterized by RHEED, XRD, AFM, and Hall effect measurements. Doping concentrations between 10 20 cm -3 and 10 18 cm -3 have been achieved. Dark current-voltage measurements have been used to indicate stability of the electrode in aqueous conditions in less than -0.5 V vs RHE. Future work will include further investigations into carrier dynamics via transient absorption spectroscopy and continual development of a tandem, ZnTe-based photocathode.
利用太阳能驱动光催化二氧化碳还原反应(CO 2 RR)提供了一种不需要外部电源就能产生碳氢化合物和含氧燃料的有吸引力的途径。碲化锌(Zinc telluride, ZnTe)是一种II-VI型半导体材料，由于其具有适合CO 2还原反应电位的带隙排列、化学稳定性和较强的p型特性，被认为是一种很有前途的光电阴极材料。利用分子束外延技术(MBE)合成了单晶和外延层，以更深入地了解单晶ZnTe薄膜与CO 2饱和电解质之间的基本电荷输运和反应机制。这些发现具有重要的基础意义，对于设计高效的串联太阳能燃料发电机，用于无辅助的光电化学CO 2 r。外延允许在很大的载流子浓度范围内高度控制薄膜的掺杂。本文主要研究了氮掺杂p型ZnTe的MBE合成和表征。在340-360℃(100)取向GaAs上生长200 nm未掺杂ZnTe缓冲层和100 nm掺杂ZnTe缓冲层的薄膜，通过RHEED、XRD、AFM和霍尔效应测量对其进行了表征。掺杂浓度在10 - 20 cm -3和10 - 18 cm -3之间已经实现。暗电流-电压测量已用于指示电极在低于-0.5 V vs RHE的水条件下的稳定性。未来的工作将包括通过瞬态吸收光谱进一步研究载流子动力学，并继续开发串联的znte基光电阴极。
{"title":"Growth and Photoelectrochemical Characterization of Epitaxial ZnTe Photocathodes for Carbon Dioxide Reduction","authors":"Lily Shiau, Harry A. Atwater","doi":"10.1149/ma2023-01372193mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01372193mtgabs","url":null,"abstract":"Harnessing solar energy to drive photocatalytic carbon dioxide reduction reactions (CO 2 RR) provides an appealing pathway to generate hydrocarbon and oxygenated fuels without an external power source. Zinc telluride (ZnTe) is a II-VI semiconductor which has been identified as a promising photocathode material due to its suitable band gap alignments to CO 2 reduction reaction potentials, chemical stability, and strong p-type character. Using molecular beam epitaxy (MBE), single crystal and epitaxial layers are synthesized to gain a deeper understanding of fundamental charge transport and reactivity mechanisms between the single crystal ZnTe thin film and the CO 2 -saturated electrolyte. These findings are of fundamental interest and are also critical to the design of efficient tandem solar fuels generators for unassisted photoelectrochemical CO 2 R. Epitaxy allows for highly controlled doping of the thin films over a large range of carrier concentrations. This work focuses largely on the synthesis and characterization of nitrogen doped p-type ZnTe via MBE. Films grown in the temperature range of 340–360ºC on GaAs of (100) orientation with a 200 nm undoped ZnTe buffer layer and a 100 nm doped ZnTe layer have been characterized by RHEED, XRD, AFM, and Hall effect measurements. Doping concentrations between 10 20 cm -3 and 10 18 cm -3 have been achieved. Dark current-voltage measurements have been used to indicate stability of the electrode in aqueous conditions in less than -0.5 V vs RHE. Future work will include further investigations into carrier dynamics via transient absorption spectroscopy and continual development of a tandem, ZnTe-based photocathode.","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088898","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 : 2023-08-28DOI: 10.1149/ma2023-01372132mtgabs
Ann L Greenaway
A half-century of research has positioned direct photoelectrochemical (PEC) fuel generation as a promising technology that still requires substantial development. Work on the hydrogen evolution reaction (HER) has provided a strong basis for realizing the generation of more complex fuels through the carbon dioxide reduction reaction (CO 2 RR), but multiple challenges remain. The CO 2 RR requires larger driving forces and integration of multiple catalysts in order to selectively generate multi-carbonproducts, while still presenting many unsolved issues from HER, such stabilizing photoelectrodes under operation. In this talk I will discuss advances in the integration of multiple catalytic microenvironments in a single photoelectrochemical device, and progress toward the stabilization of photoelectrodes for fuel generation. First, I will highlight the adaptation of three-terminal tandem (3TT) photovoltaic technology to photoelectrochemical applications. In our 3TT devices, a two-junction III-V solar cell device has an additional contact, enabling two unique catalyst sites operating at different voltages under the same illumination. Idealized circuit modeling shows the promise of these 3TT devices compared to traditional two-terminal, two-junction devices, particularly with respect to spectral tolerance. We have adapted the structure of 3TT photovoltaics to function as PEC devices and developed multiple catalysts for integration into the two solution contact sites. We demonstrate progress toward light-driven cascade catalysis for multi-carbon CO 2 RR products. Second, I will highlight our approaches to protective schemes for photoelectrodes: one which is independent of semiconductor chemistry, and one which is driven by that chemistry. In the first approach, transparent conductive encapsulants (TCEs) are demonstrated as photoabsorber-agnostic protective layers. Unlike many protection schemes, these TCEs can be applied to semiconductors post-processing and without substantial modification, providing facile and robust protection. We have characterized the electrochemical performance of TCEs and demonstrate their integration with multiple semiconductors for the reduction of methyl viologen as a proxy for PEC fuel formation. In the second approach, we use the knowledge generated over fifty years of photoelectrode research to develop a new material, ZnTiN 2 , which can be directly integrated with established semiconductors and which will degrade under PEC conditions. We leverage this degradation to create protective layers which may be self-healing, and demonstrate rapid refinement of ZnTiN 2 optoelectronic properties enabling integration with other semiconductors in tandem configurations.
{"title":"(Invited) New Approaches to Photoelectrochemical Cascade Reactions and Protection of Photoelectrodes","authors":"Ann L Greenaway","doi":"10.1149/ma2023-01372132mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01372132mtgabs","url":null,"abstract":"A half-century of research has positioned direct photoelectrochemical (PEC) fuel generation as a promising technology that still requires substantial development. Work on the hydrogen evolution reaction (HER) has provided a strong basis for realizing the generation of more complex fuels through the carbon dioxide reduction reaction (CO 2 RR), but multiple challenges remain. The CO 2 RR requires larger driving forces and integration of multiple catalysts in order to selectively generate multi-carbonproducts, while still presenting many unsolved issues from HER, such stabilizing photoelectrodes under operation. In this talk I will discuss advances in the integration of multiple catalytic microenvironments in a single photoelectrochemical device, and progress toward the stabilization of photoelectrodes for fuel generation. First, I will highlight the adaptation of three-terminal tandem (3TT) photovoltaic technology to photoelectrochemical applications. In our 3TT devices, a two-junction III-V solar cell device has an additional contact, enabling two unique catalyst sites operating at different voltages under the same illumination. Idealized circuit modeling shows the promise of these 3TT devices compared to traditional two-terminal, two-junction devices, particularly with respect to spectral tolerance. We have adapted the structure of 3TT photovoltaics to function as PEC devices and developed multiple catalysts for integration into the two solution contact sites. We demonstrate progress toward light-driven cascade catalysis for multi-carbon CO 2 RR products. Second, I will highlight our approaches to protective schemes for photoelectrodes: one which is independent of semiconductor chemistry, and one which is driven by that chemistry. In the first approach, transparent conductive encapsulants (TCEs) are demonstrated as photoabsorber-agnostic protective layers. Unlike many protection schemes, these TCEs can be applied to semiconductors post-processing and without substantial modification, providing facile and robust protection. We have characterized the electrochemical performance of TCEs and demonstrate their integration with multiple semiconductors for the reduction of methyl viologen as a proxy for PEC fuel formation. In the second approach, we use the knowledge generated over fifty years of photoelectrode research to develop a new material, ZnTiN 2 , which can be directly integrated with established semiconductors and which will degrade under PEC conditions. We leverage this degradation to create protective layers which may be self-healing, and demonstrate rapid refinement of ZnTiN 2 optoelectronic properties enabling integration with other semiconductors in tandem configurations.","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088912","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 : 2023-08-28DOI: 10.1149/ma2023-01362014mtgabs
James Sweeney, Timothy Patterson, Leonard J. Bonville, Ugur Pasaogullari, Stoyan Bliznakov
Hydrogen gas is a promising green energy solution, with enormous potential for using hydrogen fuel cells to power vehicles, homes, and for portable power applications [1]. Proton exchange membrane water electrolyzers (PEMWEs) are a viable way for the production of green hydrogen, when used in conjunction with renewable energy sources such as wind and solar. A crucial component to PEMWE is the membrane electrode assembly (MEA). MEAs are susceptible to degradation from transition metal cation impurities such as Fe 2+ [2,3,4]. The presence of iron impurities is common and can come from the feed water, cell components, and piping in the system. Concentrations of parts per million (PPM) of iron impurities have been shown to be extremely detrimental to cell performance [3, 4]. However, little work has been done to show the effects of concentrations in the parts per billion (PPB) range. Understanding the impact of Fe 2+ impurities with very low concentrations in the water stream in PEMWEs on their performance is needed to assess and improve the durability of PEMWEs. In this work, several cells assembled with MEAs with active area of 5 cm 2 have been evaluated, and the impact of low-level iron impurities on their performance has been comprehensively studied. A baseline performance was established by testing a cell in pure DI water before the feedstock was replaced with stock solutions containing Fe 2+ ions with various concentration in the low PPB range. The cells were tested at 50 o C, and constant current of 1.8 A/cm 2 for up to 500 hrs. Diagnostic tests were taken every 25 hours, which included polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Water samples were taken every day and analyzed by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), to monitor the Fe concentration in the feedstock water. In addition, water samples from the cathode were taken to investigate the fluoride emission rate (FER), to better understand membrane degradation. The findings from these experiments help to better understand the performance of PEMWEs, as well as the degradation mechanisms governing the performance loss in the MEA. References: [1] Carmo, M., Fritz, D. L., Mergel, J., & Stolten, D. (2013). A comprehensive review on PEM water electrolysis. International journal of hydrogen energy , 38 (12), 4901-4934. [2] Xu, S., Wang, X., Zhang, L., Sun, S., Li, G., Zhang, M., ... & Zhu, B. (2020). The Fe3+ role in decreasing the activity of Nafion-bonded IrO2 catalyst for proton exchange membrane water electrolyser. International Journal of Hydrogen Energy , 45 (30), 15041-15046. [3] Marocco, P., Sundseth, K., Aarhaug, T., Lanzini, A., Santarelli, M., Barnett, A. O., & Thomassen, M. (2021). Online measurements of fluoride ions in proton exchange membrane water electrolysis through ion chromatography. Journal of Power Sources , 483 , 229179. [4] Li, N., Araya, S. S., Cui, X., & Kær, S. K. (2020). The effects of
{"title":"Impact of Iron Impurities on the Performance of PEM Water Electrolyzers","authors":"James Sweeney, Timothy Patterson, Leonard J. Bonville, Ugur Pasaogullari, Stoyan Bliznakov","doi":"10.1149/ma2023-01362014mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01362014mtgabs","url":null,"abstract":"Hydrogen gas is a promising green energy solution, with enormous potential for using hydrogen fuel cells to power vehicles, homes, and for portable power applications [1]. Proton exchange membrane water electrolyzers (PEMWEs) are a viable way for the production of green hydrogen, when used in conjunction with renewable energy sources such as wind and solar. A crucial component to PEMWE is the membrane electrode assembly (MEA). MEAs are susceptible to degradation from transition metal cation impurities such as Fe 2+ [2,3,4]. The presence of iron impurities is common and can come from the feed water, cell components, and piping in the system. Concentrations of parts per million (PPM) of iron impurities have been shown to be extremely detrimental to cell performance [3, 4]. However, little work has been done to show the effects of concentrations in the parts per billion (PPB) range. Understanding the impact of Fe 2+ impurities with very low concentrations in the water stream in PEMWEs on their performance is needed to assess and improve the durability of PEMWEs. In this work, several cells assembled with MEAs with active area of 5 cm 2 have been evaluated, and the impact of low-level iron impurities on their performance has been comprehensively studied. A baseline performance was established by testing a cell in pure DI water before the feedstock was replaced with stock solutions containing Fe 2+ ions with various concentration in the low PPB range. The cells were tested at 50 o C, and constant current of 1.8 A/cm 2 for up to 500 hrs. Diagnostic tests were taken every 25 hours, which included polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Water samples were taken every day and analyzed by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), to monitor the Fe concentration in the feedstock water. In addition, water samples from the cathode were taken to investigate the fluoride emission rate (FER), to better understand membrane degradation. The findings from these experiments help to better understand the performance of PEMWEs, as well as the degradation mechanisms governing the performance loss in the MEA. References: [1] Carmo, M., Fritz, D. L., Mergel, J., & Stolten, D. (2013). A comprehensive review on PEM water electrolysis. International journal of hydrogen energy , 38 (12), 4901-4934. [2] Xu, S., Wang, X., Zhang, L., Sun, S., Li, G., Zhang, M., ... & Zhu, B. (2020). The Fe3+ role in decreasing the activity of Nafion-bonded IrO2 catalyst for proton exchange membrane water electrolyser. International Journal of Hydrogen Energy , 45 (30), 15041-15046. [3] Marocco, P., Sundseth, K., Aarhaug, T., Lanzini, A., Santarelli, M., Barnett, A. O., & Thomassen, M. (2021). Online measurements of fluoride ions in proton exchange membrane water electrolysis through ion chromatography. Journal of Power Sources , 483 , 229179. [4] Li, N., Araya, S. S., Cui, X., & Kær, S. K. (2020). The effects of","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088913","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 : 2023-08-28DOI: 10.1149/ma2023-01442410mtgabs
Sumin Lee, Sung Yul Lim
Environmental pollution and global warming have become enormous problems all over the world. At the United Nations Climate Change Conference, carbon neutrality was proposed as a way to solve this problem through the Paris Agreement in 2015. To achieve zero net carbon dioxide emissions, research on how to obtain energy from renewable energy resources has been intensively conducted. Among various candidates of renewable chemical fuels, green H 2 , produced by water electrolysis is considered as one of the promising, next generation chemical fuels. Almost 97% of earth’s water resources exist as seawater. Moreover, seawater has an advantage that it can be used as an electrolyte owing to the various ions, existing naturally. Therefore, one of the ultimate goals in green H 2 generation is to directly utilize seawater as the electrolyte source. Although Pt-group materials (PGMs) are well known catalysts in hydrogen evolution reaction (HER) but one of the main challenges for wide commercialization with PGMs is its high cost and scarcity. In order to overcome this issue, research on HER catalysts using non-PGM (NPGM) has been intensively performed. Among various NPGM elements, Ni−Mo has great potential for electrocatalysts in HER owing to its cost effectiveness as well as their high electrocatalytic activities in wide pH range of electrolytes. It is well known that not only the electrocatalytic activity in HER, mainly originating from chemical compositions at the surface, but also the physical surface properties, especially the surface wettability, play an important role to regulate the electrocatalytic performance. The evolved bubbles by the HER form the solid−gas−liquid interfaces, which results in the turn-off of the active sites toward electrochemical reactions until the gas bubbles remove from the electrocatalytic surface. Previous studies reveal that this dynamic, evolutionary behavior of surface active sites by the bubble growth/departure significantly influence the electrocatalytic performance. Herein, we demonstrate the Ni−Mo-based material as the electrocatalyst toward HER in simulated seawater, which is 0.5 M phosphate buffer with 0.6 M NaCl. The electrocatalytic layers are deposited by simple electrodeposition with the aminated graphene oxide (aGO) to form composites (aGO/NiMo). The addition of aGO in Ni−Mo does not influence the electrocatalytic activity in HER, exhibiting nearly the same cyclic voltammograms with pure NiMo. Interestingly, the long-term performance of aGO/NiMo, however, is observed when compared to the pure NiMo. The enhanced durability by chronopotentiometric measurements in the aGO/NiMo is ascribed to the improved surface wettability, originating from added aGO. The images taken by high-speed camera clearly show that the H 2 bubbles with smaller sizes at the surface of aGO/NiMo but much larger density than the ones at pure NiMo are observed. These phenomena denotes that the regeneration rate of active sites by bubbles depar
环境污染和全球变暖已经成为世界范围内的巨大问题。在2015年的联合国气候变化大会上，碳中和被提议通过《巴黎协定》来解决这一问题。为了实现二氧化碳净零排放，如何从可再生能源中获取能源的研究已经深入开展。在可再生化学燃料的众多候选中，由水电解产生的绿色h2被认为是最有前途的下一代化学燃料之一。地球上几乎97%的水资源以海水的形式存在。此外，海水的优点是可以作为电解质使用，因为海水中含有多种天然存在的离子。因此，直接利用海水作为电解液来源是绿色制氢的最终目标之一。pt基材料(Pt-group materials, PGMs)是一种广泛应用于析氢反应(HER)的催化剂，但其高成本和稀缺性是阻碍其广泛商业化的主要挑战之一。为了克服这一问题，人们对非pgm (NPGM)催化剂进行了大量的研究。在各种NPGM元素中，Ni−Mo由于其成本效益和在宽pH范围电解质中的高电催化活性而具有很大的电催化剂潜力。众所周知，HER的电催化活性主要来源于其表面的化学成分，而且其表面物理性质，特别是表面润湿性对电催化性能起着重要的调节作用。由HER产生的气泡形成固-气-液界面，导致电化学反应的活性位点关闭，直到气泡从电催化表面移除。先前的研究表明，气泡生长/离开对表面活性位点的动态演化行为显著影响电催化性能。在此，我们证明了Ni−mo基材料在模拟海水中作为HER的电催化剂，该材料是0.5 M磷酸盐缓冲液和0.6 M NaCl。电催化层通过简单的电沉积与胺化氧化石墨烯(aGO)形成复合材料(aGO/NiMo)。在Ni−Mo中添加aGO不影响HER的电催化活性，表现出与纯NiMo几乎相同的循环伏安图。然而，有趣的是，与纯NiMo相比，aGO/NiMo的长期性能得到了观察。通过计时电位测量，aGO/NiMo的耐用性得到了增强，原因在于添加了aGO，表面润湿性得到了改善。高速相机拍摄的图像清楚地表明，在aGO/NiMo表面观察到的h2气泡尺寸比纯NiMo表面小，但密度比纯NiMo表面大。这些现象表明，aGO/NiMo中气泡离开表面的活性位点再生速率远高于未添加aGO的NiMo，表明aGO有利于提高表面润湿性。在恒电流密度下，纯NiMo上h2气泡停留时间的延长增加了单个活性位点的实际过电位，导致HER中电催化活性的降解速度加快。原子力显微镜下的表面粗糙度测量和接触角也支持了aGO/NiMo和NiMo之间表面润湿性的物理性质。我们的研究有助于电催化表面物理性质的基本设计，从而简单地提高HER中的电化学性能。
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Pub Date : 2023-08-28DOI: 10.1149/ma2023-01382250mtgabs
Alanna M. Gado, Deniz Ipekçi, Stoyan Bliznakov, Leonard J. Bonville, Jeffrey McCutcheon, Radenka Maric
Alkaline water electrolysis (AWE) is a promising technology for carbon capture [1]. Anion exchange membrane water electrolyzers (AEMWEs) utilize low-cost, non-precious metal materials, providing an economically viable alternative to more expensive proton exchange membrane water electrolyzers (PEMWEs). While PEMWEs can operate at much higher current densities, they require noble metal catalysts and titanium components for the high potential environment anode [1]. The implementation of a bipolar membrane (BPM) will allow both HER and OER to occur under kinetically favorable conditions [2, 3] by combining both thin AEM and thin PEM layers within a single membrane. AEMs, PEMs, and BPMs have been tested in CO2RR electrolyzers [4]. The BPM may provide a pathway to combine the advantages of both AEMs and PEMs for CO 2 reduction. Altering both the membrane and CCM is a focus in the research and development in CO 2 RR electrolyzers. Lee et al. [5] explored the use of a porous membrane for CO2 reduction. While work can be done to improve performance and crossover, the porous membrane provided excellent mechanical properties and good economic potential. There has been some work done on developing bifunctional membranes for water electrolysis and CO 2 reduction [3, 6, 7]. Two key issues with operation of a CO 2 RR electrolyzer with a BPM is the reactant CO 2 that is lost to the AEM and PEM membrane layer interface and the instability of the cell. Both issues contribute to a significant decrease in performance and faradaic efficiency in product conversion. Development of the BPM, both on the membrane’s fabrication and configuration, and electrode layers, needs to be explored to reach higher performances and longer lifespans. In this work, reactive spray deposition technology (RSDT) was used to fabricate electrodes on a UConn fabricated bipolar membrane. Testing of each configuration was conducted as both an AEM water electrolyzer and CO 2 RR electrolyzer. Polarization, electrochemical impedance spectroscopy, electrochemical equivalent circuits, and distribution of relaxation times were used to investigate cell performance and durability. References [1] B. Mayerhofer, D. McLaughlin, T. Bohm, M. Hegelheimer, D. Seeberger, and S. Thiele, “Bipolar membrane electrode assemblies for water electrolysis,” ACS applied energy materials, vol. 3, no. 10, pp. 9635–9644, 2020. [2] J. Xu, I. Amorim, Y. Li, J. Li, Z. Yu, B. Zhang, A. Araujo, N. Zhang, and L. Liu, “Stable overall water splitting in an asymmetric acid/alkaline electrolyzer comprising a bipolar membrane sandwiched by bifunctional cobalt-nickel phosphide nanowire electrodes,” Carbon Energy, vol. 2, no. 4, pp. 646–655, 2020. [3] Q. Lei, B. Wang, P. Wang, and S. Liu, “Hydrogen generation with acid/alkaline amphoteric water electrolysis,” Journal of Energy Chemistry, vol. 38, pp. 162–169, 2019. [13] W. H. Lee, K. Kim, C. Lim, Y. J. Ko, Y. J. Hwang, B. K. Min, U. Lee, and H. S. Oh, “New strategies for economically f
碱性电解(AWE)是一种很有前途的碳捕获技术[1]。阴离子交换膜水电解槽(AEMWEs)利用低成本的非贵金属材料，为更昂贵的质子交换膜水电解槽(PEMWEs)提供了一种经济可行的替代方案。虽然PEMWEs可以在更高的电流密度下工作，但它们需要贵金属催化剂和钛组件来作为高电位环境阳极[1]。双极膜(BPM)的实现将允许HER和OER在动力学有利的条件下发生[2,3]，通过在单个膜内结合薄AEM和薄PEM层。已经在CO2RR电解槽中对AEMs、pem和bpm进行了测试[4]。BPM可以提供一条途径，将AEMs和PEMs的优势结合起来减少二氧化碳。改变膜和CCM是co2 RR电解槽研究和发展的重点。Lee等人[5]探索了使用多孔膜进行CO2还原。虽然还需要改进性能和交叉，但多孔膜具有优异的机械性能和良好的经济潜力。在开发用于水电解和CO 2还原的双功能膜方面已经做了一些工作[3,6,7]。使用BPM的CO 2 RR电解槽运行的两个关键问题是反应物CO 2损失到AEM和PEM膜层界面以及电解槽的不稳定性。这两个问题都导致产品转换的性能和效率显著下降。BPM的发展，无论是在膜的制造和配置，还是电极层，都需要探索以达到更高的性能和更长的寿命。在这项工作中，使用反应喷涂沉积技术(RSDT)在UConn制造的双极膜上制备电极。分别作为AEM水电解槽和co2 RR电解槽对每种配置进行了测试。利用极化、电化学阻抗谱、电化学等效电路和弛豫时间分布来研究电池的性能和耐久性。[1]刘建军，刘建军，刘建军，“水电解膜电极的研究进展”，能源工程学报，vol. 3, no. 1。10, pp. 9635-9644, 2020。[2]徐建军，李勇，李军，于忠，张斌，张伯杰，张宁，刘磊，“双功能磷化钴-镍纳米线电极在非对称酸/碱性电解槽中的稳定整体水分解，”碳能，第2卷，第2期。4, pp. 646-655, 2020。[3]雷强，王斌，王平，刘顺生，“酸碱两性电解制氢”，能源化学，vol. 38, pp. 162-169, 2019。[13] w·h·李,k金,c . Lim y . j . Ko y . j .黄b . k . Min Lee,和h . s .哦,”新战略在经济上可行的CO 2电解还原使用多孔膜在零距离配置中,“材料化学杂志》9卷,第16177 - 16169页,2021年8 [4]d·a·塞尔瓦托c . m . Gabardo雷耶斯,c·p·奥布莱恩s Holdcroft p . Pintauro b . Bahar m . Hickner c . Bae d·辛顿e·h·萨金特和c·p·Berlinguette“阴离子交换膜forCO 2电解槽设计”[5]李文辉，金锴，高英杰，黄艳娟，闵宝康，李玉，吴海生，“零间隙结构多孔膜电还原CO 2的新方法”，环境科学，vol. 6, pp. 339-348, 4202[6]李伟，殷志刚，王国光，李忠，魏峰，魏晓霞，彭慧，胡晓玲，肖丽，卢建军，庄磊，“高电流密度下高效CO电解co2和纯水制备乙烯的双功能离子单体，”材料化学学报，vol. 9, pp. 16169-16177, 2021[7]刘树明，刘树明，刘永强，刘志强，刘志强，李国光，黄建明，谢克明，刘志强，等，“电合成多碳产品的CO 2再生效率超过85%，”能源工程学报，第6卷，第7期。8, pp. 2952-2959, 2021。
{"title":"Investigation of the Performance and Durability of Reactive Spray Deposition Fabricated Electrodes on a Bifunctional Membrane for Alkaline Water Electrolysis and CO<sub>2</sub> Reduction Reaction","authors":"Alanna M. Gado, Deniz Ipekçi, Stoyan Bliznakov, Leonard J. Bonville, Jeffrey McCutcheon, Radenka Maric","doi":"10.1149/ma2023-01382250mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01382250mtgabs","url":null,"abstract":"Alkaline water electrolysis (AWE) is a promising technology for carbon capture [1]. Anion exchange membrane water electrolyzers (AEMWEs) utilize low-cost, non-precious metal materials, providing an economically viable alternative to more expensive proton exchange membrane water electrolyzers (PEMWEs). While PEMWEs can operate at much higher current densities, they require noble metal catalysts and titanium components for the high potential environment anode [1]. The implementation of a bipolar membrane (BPM) will allow both HER and OER to occur under kinetically favorable conditions [2, 3] by combining both thin AEM and thin PEM layers within a single membrane. AEMs, PEMs, and BPMs have been tested in CO2RR electrolyzers [4]. The BPM may provide a pathway to combine the advantages of both AEMs and PEMs for CO 2 reduction. Altering both the membrane and CCM is a focus in the research and development in CO 2 RR electrolyzers. Lee et al. [5] explored the use of a porous membrane for CO2 reduction. While work can be done to improve performance and crossover, the porous membrane provided excellent mechanical properties and good economic potential. There has been some work done on developing bifunctional membranes for water electrolysis and CO 2 reduction [3, 6, 7]. Two key issues with operation of a CO 2 RR electrolyzer with a BPM is the reactant CO 2 that is lost to the AEM and PEM membrane layer interface and the instability of the cell. Both issues contribute to a significant decrease in performance and faradaic efficiency in product conversion. Development of the BPM, both on the membrane’s fabrication and configuration, and electrode layers, needs to be explored to reach higher performances and longer lifespans. In this work, reactive spray deposition technology (RSDT) was used to fabricate electrodes on a UConn fabricated bipolar membrane. Testing of each configuration was conducted as both an AEM water electrolyzer and CO 2 RR electrolyzer. Polarization, electrochemical impedance spectroscopy, electrochemical equivalent circuits, and distribution of relaxation times were used to investigate cell performance and durability. References [1] B. Mayerhofer, D. McLaughlin, T. Bohm, M. Hegelheimer, D. Seeberger, and S. Thiele, “Bipolar membrane electrode assemblies for water electrolysis,” ACS applied energy materials, vol. 3, no. 10, pp. 9635–9644, 2020. [2] J. Xu, I. Amorim, Y. Li, J. Li, Z. Yu, B. Zhang, A. Araujo, N. Zhang, and L. Liu, “Stable overall water splitting in an asymmetric acid/alkaline electrolyzer comprising a bipolar membrane sandwiched by bifunctional cobalt-nickel phosphide nanowire electrodes,” Carbon Energy, vol. 2, no. 4, pp. 646–655, 2020. [3] Q. Lei, B. Wang, P. Wang, and S. Liu, “Hydrogen generation with acid/alkaline amphoteric water electrolysis,” Journal of Energy Chemistry, vol. 38, pp. 162–169, 2019. [13] W. H. Lee, K. Kim, C. Lim, Y. J. Ko, Y. J. Hwang, B. K. Min, U. Lee, and H. S. Oh, “New strategies for economically f","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088965","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}
The conventional catalyst of polymer electrolyte fuel cell (PEFC) is a platinum which is categorized as precious metal with very high-cost material, and its performance is limited in principal. From this point of view, the non-precious metal electrocatalyst should be required. We have focused and studied group 4 and 5 metal oxide-based electrocatalyst as non-platinum catalysts for the oxygen reduction reaction (ORR) because of low-cost, abundant reserves, and high stability in acidic electrolytes [1-2]. We found that titanium oxide prepared from TiOTPyzPz supported on multi-walled carbon nanotubes had superior ORR activity [3]. On the other hand, it was published as an international patent that the addition of other elements such as Fe and Ni is affected to enhance the ORR activity of Ti oxide-based electrocatalyst [4]. We have also applied for the TiOTPyzPz as a starting material with Fe, Ni, and Zn addition to enhance the ORR activity of Ti oxide-based electrocatalyst [5-6]. In this study, we have investigated the addition effects of Zn and Fe for Ti oxide-based electrocatalyst on the catalytic activity for the ORR. 2,3-Dicyanopyrazine, urea, and Ti isopropoxide were dissolved in quinoline and refluxed to synthesize TiOTPyzPz. Iron acetate and zinc acetate were also added to dissolve in quinoline to obtain the Fe and Zn-added TiOTPyzPz as a starting material. These starting materials were mixed with carbon nanotube by ball-milling to prepare the precursors. These precursors were heat-treated under low oxygen partial pressure at 900 o C for 3 h to obtain the oxide-based electrocatalyst powder. The catalyst powder was dispersed into 1-propanol with Nafion solution to prepare a catalyst ink. The ink was dropped on a glassy carbon rod to use as a working electrode in electrochemical measurement. Electrochemical measurements were performed in 0.5 mol dm -3 H 2 SO 4 at 30 o C with a conventional 3-electrode cell. A reversible hydrogen electrode (RHE) and a glassy carbon plate were used as used as a reference and counter electrode, respectively. Slow scan voltammetry (SSV) was performed at a scan rate of 5 mV s -1 from 0.2 V to 1.2 V vs. RHE under O 2 and N 2 . The ORR current ( i ORR ) was determined by calculating the difference between the current under O 2 and N 2 . Figure 1 shows the ORR polarization curves Fe and/or Zn addition to the Ti oxide-based electrocatalysts. The Fe and Zn added Ti oxide-based electrocatalyst (Fe,Zn-TiO x ) was obviously the highest activity for the ORR, and it was higher ORR activity than Fe added Ti oxide-based electrocatalyst (Fe-TiO x ), Zn added Ti oxide-based electrocatalyst (Zn-TiO x ), and Ti oxide-based electrocatalyst (TiO x ) without addition. It reveals that the addition of Fe and Zn was found to be effective for enhancing the ORR activity, and Fe addition was more effective than Zn addition for enhancing the ORR activity. XRD pattern of TiO x shows several peaks identified TiO 2 -Rutile and TiC 0.3 N 0.7 whi
聚合物电解质燃料电池(PEFC)的传统催化剂是铂，铂是一种非常昂贵的贵金属材料，其性能在原则上是有限的。从这个角度来看，应该需要非贵金属电催化剂。由于4族和5族金属氧化物基电催化剂成本低、储量丰富、在酸性电解质中稳定性高，我们重点研究了它们作为氧还原反应(ORR)的非铂催化剂[1-2]。我们发现多壁碳纳米管负载TiOTPyzPz制备的氧化钛具有优异的ORR活性[3]。另一方面，通过影响Fe和Ni等其他元素的加入来增强Ti氧化物基电催化剂的ORR活性被作为国际专利公布[4]。我们还申请了TiOTPyzPz作为起始材料，加入Fe、Ni和Zn，以增强Ti氧化物基电催化剂的ORR活性[5-6]。在本研究中，我们研究了Zn和Fe对氧化钛基电催化剂的催化活性的影响。将2,3-双氰吡嗪、尿素和异丙醇钛溶解在喹啉中回流合成TiOTPyzPz。在喹啉中加入乙酸铁和乙酸锌溶解，得到以铁和锌为起始原料的TiOTPyzPz。将这些起始材料与碳纳米管通过球磨混合制备前驱体。将这些前驱体在900℃的低氧分压下热处理3 h，得到氧化物基电催化剂粉末。将催化剂粉末与Nafion溶液分散到1-丙醇中，制备催化剂油墨。将墨水滴在玻璃碳棒上，作为电化学测量中的工作电极。电化学测量在30℃、0.5 mol dm -3 h2so4中进行。采用可逆氢电极(RHE)和玻碳板分别作为参比电极和反电极。慢扫描伏安法(SSV)的扫描速率为5 mV s -1，从0.2 V到1.2 V相对于RHE在o2和n2下进行。ORR电流(i ORR)是通过计算o2和n2下电流的差值来确定的。图1显示了在Ti基电催化剂中加入Fe和/或Zn后的ORR极化曲线。Fe和Zn加Ti基电催化剂(Fe,Zn-TiO x)的ORR活性最高，且ORR活性高于Fe加Ti基电催化剂(Fe-TiO x)、Zn加Ti基电催化剂(Zn-TiO x)和未加Ti基电催化剂(TiO x)。结果表明，Fe和Zn对ORR活性均有增强作用，且Fe对ORR活性的增强效果优于Zn。tiox的XRD谱图显示出tio2 -金红石和tio0.3 n0.7的几个峰，而Fe- tiox、zn - tiox和Fe、zn - tiox的XRD谱图也显示出与tiox相似的几个峰。ICP分析结果表明，Fe、Zn- tiox中Ti和Fe的含量与前驱体中制备量相近，但Zn的含量低于检测限。从SEM图像来看，zn - tiox和Fe, zn - tiox在粉末中的空间比Fe- tiox和tiox大。基于以上结果，我们认为与氧化锆基电催化剂[8]类似，添加Zn会影响TiO x电化学表面积的增加，添加Fe会影响TiO x中活性位点的形成[7]。致谢:作者感谢新能源和工业技术发展组织(NEDO)和ENEOS Tonen一般研究/发展鼓励&奖学金基金会的财政支持。参考文献A. Ishihara, Y. Ohgi, K. Matsuzawa, S. Mitsushima和K. Ota，电化学。学报，55,8005(2010)。A.石原，S.富中，S.三岛，H.今井，H.今井，O.杉野，和K.太田，Curr。当今。Electrochem。， 21, 234(2020)。S. Tominaka, A. Ishihara, T. Nagai，和K. Ota, ACS Omega, 25209(2017)。高桥明，王晓明，张晓明，张晓明，氧还原膜燃料电池的研究进展，高分子材料学报，2013/ 01 - 01。Matsuzawa, M. Obata, Y. Takeuchi, Y. Ohgi, K. Ikegami, T. Nagai, R. Monden和A. Ishihara, ECS Trans。， 108(7)， 181(2022)。Matsuzawa, M. Obata, Y. Takeuchi, Y. Ohgi, K. Ikegami, T. Nagai, R. Monden和A. Ishihara, ECS Trans。， 108(7)， 189(2022)。陶宏根。石原，王晓明，王晓明，等。中国科学:自然科学学报，2007,24(1)。Y. Takeuchi, K. Watanabe, K. Matsuzawa, T. Nagai, K. Ikegami, R. Monden和A. Ishihara, Chem。列托人。， 51, 927(2022)。图1
{"title":"Fe and Zn Addition Effects of Ti Oxide-Based Electrocatalyst on Catalytic Activity for Oxygen Reduction Reaction","authors":"Koichi Matsuzawa, Momo Obata, Yuu Takeuchi, Yoshiro Ohgi, Takaaki Nagai, Ryuji Monden, Akimitsu Ishihara","doi":"10.1149/ma2023-01382244mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01382244mtgabs","url":null,"abstract":"The conventional catalyst of polymer electrolyte fuel cell (PEFC) is a platinum which is categorized as precious metal with very high-cost material, and its performance is limited in principal. From this point of view, the non-precious metal electrocatalyst should be required. We have focused and studied group 4 and 5 metal oxide-based electrocatalyst as non-platinum catalysts for the oxygen reduction reaction (ORR) because of low-cost, abundant reserves, and high stability in acidic electrolytes [1-2]. We found that titanium oxide prepared from TiOTPyzPz supported on multi-walled carbon nanotubes had superior ORR activity [3]. On the other hand, it was published as an international patent that the addition of other elements such as Fe and Ni is affected to enhance the ORR activity of Ti oxide-based electrocatalyst [4]. We have also applied for the TiOTPyzPz as a starting material with Fe, Ni, and Zn addition to enhance the ORR activity of Ti oxide-based electrocatalyst [5-6]. In this study, we have investigated the addition effects of Zn and Fe for Ti oxide-based electrocatalyst on the catalytic activity for the ORR. 2,3-Dicyanopyrazine, urea, and Ti isopropoxide were dissolved in quinoline and refluxed to synthesize TiOTPyzPz. Iron acetate and zinc acetate were also added to dissolve in quinoline to obtain the Fe and Zn-added TiOTPyzPz as a starting material. These starting materials were mixed with carbon nanotube by ball-milling to prepare the precursors. These precursors were heat-treated under low oxygen partial pressure at 900 o C for 3 h to obtain the oxide-based electrocatalyst powder. The catalyst powder was dispersed into 1-propanol with Nafion solution to prepare a catalyst ink. The ink was dropped on a glassy carbon rod to use as a working electrode in electrochemical measurement. Electrochemical measurements were performed in 0.5 mol dm -3 H 2 SO 4 at 30 o C with a conventional 3-electrode cell. A reversible hydrogen electrode (RHE) and a glassy carbon plate were used as used as a reference and counter electrode, respectively. Slow scan voltammetry (SSV) was performed at a scan rate of 5 mV s -1 from 0.2 V to 1.2 V vs. RHE under O 2 and N 2 . The ORR current ( i ORR ) was determined by calculating the difference between the current under O 2 and N 2 . Figure 1 shows the ORR polarization curves Fe and/or Zn addition to the Ti oxide-based electrocatalysts. The Fe and Zn added Ti oxide-based electrocatalyst (Fe,Zn-TiO x ) was obviously the highest activity for the ORR, and it was higher ORR activity than Fe added Ti oxide-based electrocatalyst (Fe-TiO x ), Zn added Ti oxide-based electrocatalyst (Zn-TiO x ), and Ti oxide-based electrocatalyst (TiO x ) without addition. It reveals that the addition of Fe and Zn was found to be effective for enhancing the ORR activity, and Fe addition was more effective than Zn addition for enhancing the ORR activity. XRD pattern of TiO x shows several peaks identified TiO 2 -Rutile and TiC 0.3 N 0.7 whi","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088980","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 : 2023-08-28DOI: 10.1149/ma2023-01442380mtgabs
Varsha M V, Gomathi Nageswaran
Metal-organic frameworks (MOFs) are an attractive class of highly ordered, crystalline, porous materials that exhibit large specific surface area, porosity, tunable structure and ease of functionalization. The presence of a number of uniformly dispersed metal components i.e. catalytic molecular units throughout the framework make MOF based materials a potential candidate for electrochemical sensing studies. However, pristine MOFs have the inherent drawbacks such as the inferior electrical conductivity that need to be addressed for its direct application in sensing platforms. In this context, the design of redox-active and highly conducting MOF is a research hotspot in the material science since it can overcome the inferior electrocatalytic activity of chemically modified electrodes (CME) based on pristine MOF. The integration of highly conducting metals into the framework is an efficient method to enhance the electric conductivity and thereby the electrochemical activity of synthesized material. The synergistic effect arising from the combination of different metal ions changes the surface electronic structure of MOF and thereby improve the mobility of charge carriers. Herein, an electrochemical sensing platform based on ruthenium doped Cu-MOF was developed for the sensitive detection of ciprofloxacin antibiotic. This work focuses on the synthetic strategy of Ru-Cu-TMA where the parent MOF, Cu-TMA, was synthesised by a facile room temperature mixing at ambient pressure. The present synthetic method is found to be a simple and efficient method compared to the conventional solvothermal method reported commonly for MOF synthesis. The successful integration of ruthenium into Cu-MOF created a number of electrocatalytic active sites which can favour the interaction with analyte species in sensing studies. The structural features and morphology of the synthesized MOF materials were studied using different characterization techniques like XRD, IR, SEM, XPS etc. The porous structure of MOF combined with higher reaction kinetics due to the incorporation of ruthenium cause a synergistic effect which makes the mixed-valent MOF a promising candidate for sensing studies. The composite, Ru-Cu-TMA, prepared was used as an electrode modifier for the sensitive detection of ciprofloxacin by electrochemical technique. Initially, the electrochemical activity of the chemically modified electrodes were examined and Ru-Cu-TMA modified electrode shows the higher current and fast electron transfer which paves the way for its application as sensing material. In addition, more number of active sites formed in MOF by ruthenium doping considerably increases the sensing performance of Ru-Cu-TMA. The electrochemical oxidation of ciprofloxacin on electrode surface is confirmed as an irreversible, diffusion-controlled process. The sensor exhibited a wide linear dynamic range (2.5 – 100 µM) with a lower limit of detection (3.29 nM) and sensitivity 0.0524 µA/µM. Moreover, the senso
{"title":"A Novel Electrochemical Sensing Platform Based on Bimetallic Ru-Cu-MOF for the Voltammetric Detection of Ciprofloxacin Antibiotic","authors":"Varsha M V, Gomathi Nageswaran","doi":"10.1149/ma2023-01442380mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01442380mtgabs","url":null,"abstract":"Metal-organic frameworks (MOFs) are an attractive class of highly ordered, crystalline, porous materials that exhibit large specific surface area, porosity, tunable structure and ease of functionalization. The presence of a number of uniformly dispersed metal components i.e. catalytic molecular units throughout the framework make MOF based materials a potential candidate for electrochemical sensing studies. However, pristine MOFs have the inherent drawbacks such as the inferior electrical conductivity that need to be addressed for its direct application in sensing platforms. In this context, the design of redox-active and highly conducting MOF is a research hotspot in the material science since it can overcome the inferior electrocatalytic activity of chemically modified electrodes (CME) based on pristine MOF. The integration of highly conducting metals into the framework is an efficient method to enhance the electric conductivity and thereby the electrochemical activity of synthesized material. The synergistic effect arising from the combination of different metal ions changes the surface electronic structure of MOF and thereby improve the mobility of charge carriers. Herein, an electrochemical sensing platform based on ruthenium doped Cu-MOF was developed for the sensitive detection of ciprofloxacin antibiotic. This work focuses on the synthetic strategy of Ru-Cu-TMA where the parent MOF, Cu-TMA, was synthesised by a facile room temperature mixing at ambient pressure. The present synthetic method is found to be a simple and efficient method compared to the conventional solvothermal method reported commonly for MOF synthesis. The successful integration of ruthenium into Cu-MOF created a number of electrocatalytic active sites which can favour the interaction with analyte species in sensing studies. The structural features and morphology of the synthesized MOF materials were studied using different characterization techniques like XRD, IR, SEM, XPS etc. The porous structure of MOF combined with higher reaction kinetics due to the incorporation of ruthenium cause a synergistic effect which makes the mixed-valent MOF a promising candidate for sensing studies. The composite, Ru-Cu-TMA, prepared was used as an electrode modifier for the sensitive detection of ciprofloxacin by electrochemical technique. Initially, the electrochemical activity of the chemically modified electrodes were examined and Ru-Cu-TMA modified electrode shows the higher current and fast electron transfer which paves the way for its application as sensing material. In addition, more number of active sites formed in MOF by ruthenium doping considerably increases the sensing performance of Ru-Cu-TMA. The electrochemical oxidation of ciprofloxacin on electrode surface is confirmed as an irreversible, diffusion-controlled process. The sensor exhibited a wide linear dynamic range (2.5 – 100 µM) with a lower limit of detection (3.29 nM) and sensitivity 0.0524 µA/µM. Moreover, the senso","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135088982","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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