ECS Meeting Abstracts最新文献

{"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}

{"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}

{"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}

{"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}

{"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}

{"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}

{"title":"Enhanced Hydrogen Evolution Performance of Ni−Mo-Based Electrocatalysts in Seawater by Controlling Surface Wettability","authors":"Sumin Lee, Sung Yul Lim","doi":"10.1149/ma2023-01442410mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01442410mtgabs","url":null,"abstract":"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","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":"135088942","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}

{"title":"Investigation of the Performance and Durability of Reactive Spray Deposition Fabricated Electrodes on a Bifunctional Membrane for Alkaline Water Electrolysis and CO₂ 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}

{"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}

{"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}