ECS Meeting Abstracts最新文献

{"title":"Study on Exsolution Process of Sr₂FeMo_0.6Ni_0.4O₆via in Situ Cathodic Polarization","authors":"Leonardo Duranti, Andrea Felli, Marcello Marelli, Melodj Dosa, Elisabetta Di Bartolomeo, Marco Piumetti, Marta Boaro","doi":"10.1149/ma2023-015498mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-015498mtgabs","url":null,"abstract":"Solid oxide cells (SOCs) are nowadays one of the most promising energy conversion technologies, to accelerate and promote the ongoing energy transition 1,2 , based on the use of renewable resources. These devices in fact allow the development of valuable low carbon footprint power-to-X (X= power, fuels) chains of energy conversion and storage 3 . In this respect is crucial the design of innovative, cost-effective materials and processes for more and more versatile and reversible devices. In the last decade, simple perovskite (ABO 3 ) and double perovskite (A 2 BBʹO 6 ) oxide have been proved to be a valuable alternative to cermet SOC electrodes, thanks to their relative ease of functionalization via doping and exsolution and their mixed ionic-electron conduction 4-6 . Exsolution process is strongly dependent on the type of metal and perovskite and on methodology adopted to induce the reduction 7 . Cathodic electrochemical polarization has been demonstrated to be a valuable approach to boost the exsolution especially from titanate based structures, obtaining higher dispersions than that derived from thermal reduction 8 . In this work, we explored for the first time the behaviour of the double perovskite Sr 2 FeMo 0.6 Ni 0.4 O 6-δ (SFMN) under cathodic polarization and we investigated the impact of the structural evolution on the electrochemical performances of a multi-functional electrode for H 2 -SOFC and CO 2 -SOEC applications. SFMN was prepared by sol gel method and used to prepare supported SFMN/ La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ (LSGM)/La 0.6 Sr 0.4 Fe 0.8 Co 0.2 O 3-δ :Ce 0.9 Gd 0.1 O 2-δ (LSFCo:GDC) cells that were tested either before and after thermal or electrochemical reduction at 850°C. As already reported the thermal reduction of SFMN leads to the exsolution of metal nanoparticles (of Ni or Ni-Fe alloys) and the in situ formation of Ruddlesden-Popper phase 9 (RP). HRTEM, SEM and XRD characterizations of tested cells allowed to observe an acceleration of the structural transformation of perovskite under cathodic polarization in comparison to what observed under thermal reduction. This allows to gain insights on the role of entire transformation on the electrochemical behaviours of cells. Electrochemical properties of SFNM were investigated by EIS analysis. Distribution of relaxation times (DRT) analyses was also used to obtain further insights on the impedance of the different cell mechanisms according to their characteristic frequency. The exsolved metal nanoparticles contributed to improve the conductivity and activity of the electrode, however, also the formation of RP phase seems have a significant role, especially in the electroreduction of CO 2 . Further studies are in progress to better understand the mechanisms of interaction between the phases formed during the exsolution process and their role on SOC electrodes activity. References 1 Hauch et al., Science 370, eaba6118 (2020). 2 M.B. Mogensen et al. Clean Energy, 3 (2019) 17","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":"135088813","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":"Ternary Oxide Semiconductors and Alloys: Hope and Reality","authors":"Krishnan Rajeshwar","doi":"10.1149/ma2023-01402853mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01402853mtgabs","url":null,"abstract":"This perspective talk focuses on the history and status of new materials with targeted application in solar energy conversion. Specifically, photoelectrochemical energy conversion/solar water splitting and wide bandgap oxide semiconductors and alloys for solar windows and displays are the two targeted application areas. The Cu-M-V-O family of oxide semiconductors will be discussed in this poster. Both synthetic aspects and chemical composition-property-performance correlations will be presented. Acknowledgements. This work was primarily supported by the National Science Foundation UTA/NU Partnership for Research and Education in Materials (NSF DMR-2122128).","PeriodicalId":11461,"journal":{"name":"ECS Meeting Abstracts","volume":"49 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":"135088820","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 Study on Na_1.2Mn_0.8O_1.5F_0.5 Na-Rich Cathode Material for High Capacity and Superior Stability Sodium Solid-State Battery","authors":"Bala Krishnan Ganesan, Megala Moorthy, Yeong-A Kim, Hariharan Dhanasekaran, Jeong-Hyeon Song, Yun-Sung Lee","doi":"10.1149/ma2023-01552666mtgabs","DOIUrl":"https://doi.org/10.1149/ma2023-01552666mtgabs","url":null,"abstract":"Sodium ion batteries are considered as a cost-effective and promising alternative to lithium-ion batteries for next generation large-scale energy storage applications. However, the sluggish intercalation kinetics and poor stability plagues the efficient applications. Recently, sodium rich cathode materials are emerging as a promising system to retain high specific energy with improved durability. Benefitting from the high Na ion mobility by P2-type structure and reduced John-Teller active Mn site, improved stability has been achieved for this Na-rich cathode. In this work, we developed a high performing Na rich cathode with Sodium Manganese Oxyfluoride ( Na 1.2 Mn 0.8 O 1.5 F 0.5 ) as a battery positive electrode. The corresponding structural and electrochemical performances are analysed in solid-state battery. The highly favourable cathode architecture demonstrated a high specific capacity of 178 mAh/g at 10 mA/g in half-cell configuration. To further harness its performance, the cathode material was coupled with solid-electrolyte and interface modified anode. Solid-state battery demonstrated an enhanced capability towards ion storage and better stability.","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":"135088835","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":"(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}