D. Islamov, V. Gritsenko, T. Perevalov, V. Aliev, A. Yelisseyev, V. Pustovarov, V. Nadolinny, E. Lomonova, A. Chin
The origin of luminescence centres and traps of charge carriers in ZrO2 was studied using Raman scattering, luminescence spectroscopy, charge transport and quantum-chemical calculation. After the X-ray irradiation of the ZrO2 film, the EPR spectra from an interstitial oxygen and a negatively charged oxygen vacancy are observed. The 2.7 eV luminescence band and 5.2 eV absorption/luminescence excitation band are associated with an oxygen vacancy. Half of the Stokes shift in blue photoluminescence spectra is equal to the trap thermal activation energy 1.25 eV estimated from the charge transport experiment. Within quantum-chemical simulations and experiments on the extraction of minority carriers from silicon substrates, it was demonstrated that both electrons and holes can be trapped on oxygen vacancies in ZrO2. Hence, oxygen vacancies are supposed to operate as traps responsible for the blue luminescence band and charge transport in ZrO2.
{"title":"Oxygen Vacancies in Zirconium Oxide as the Blue Luminescence Centers and Traps Responsible for Charge Transport","authors":"D. Islamov, V. Gritsenko, T. Perevalov, V. Aliev, A. Yelisseyev, V. Pustovarov, V. Nadolinny, E. Lomonova, A. Chin","doi":"10.2139/ssrn.3582138","DOIUrl":"https://doi.org/10.2139/ssrn.3582138","url":null,"abstract":"The origin of luminescence centres and traps of charge carriers in ZrO<sub>2</sub> was studied using Raman scattering, luminescence spectroscopy, charge transport and quantum-chemical calculation. After the X-ray irradiation of the ZrO<sub>2</sub> film, the EPR spectra from an interstitial oxygen and a negatively charged oxygen vacancy are observed. The 2.7 eV luminescence band and 5.2 eV absorption/luminescence excitation band are associated with an oxygen vacancy. Half of the Stokes shift in blue photoluminescence spectra is equal to the trap thermal activation energy 1.25 eV estimated from the charge transport experiment. Within quantum-chemical simulations and experiments on the extraction of minority carriers from silicon substrates, it was demonstrated that both electrons and holes can be trapped on oxygen vacancies in ZrO<sub>2</sub>. Hence, oxygen vacancies are supposed to operate as traps responsible for the blue luminescence band and charge transport in ZrO<sub>2</sub>.","PeriodicalId":412570,"journal":{"name":"Electrochemistry eJournal","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127883086","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}
A. T. Nguyen, V. Phung, V. Mittova, H. Ngo, Thuan Ngoc Vo, My Linh Le Thi, V. Nguyen, I. Mittova, M. Le, Y. Ahn, I. Kim, Tuan Loi Nguyen
Nanostructured HoFeO3 perovskite was successfully prepared via co-precipitation of Fe3+ and Ho3+ ions in ethanol, followed by heat treatment. Analysis revealed the orthorhombic structure, uniaxial orientation, and nanograin size. This anode material exhibited excellent electrochemical properties in lithium-ion batteries including high capacity retention and Coulombic efficiency, good cyclability, low charge transfer, high Li+ diffusion coefficient, and excellent rate performance. They delivered reversible capacity of 437 mAh g-1 after 120 cycles at current density of 0.1 A g-1, a charge capacity of 299 mAh g-1 even at high current density of 10 A g-1. Outstanding performance can be ascribed to unique nanostructured perovskite. Nanosized materials offer a larger electrode/electrolyte interface, and reduce Li-ion diffusion length, improving reaction kinetics. Perovskite structure effectively prevented anode degradation during cycling, demonstrating excellent reversible storage. Kinetics of electrochemical reactions were also studied. All indicate the great potential of HoFeO3 perovskite as an anode material in LIBs.
将Fe3+和Ho3+离子在乙醇中共沉淀，然后进行热处理，成功制备了纳米HoFeO3钙钛矿。分析表明，该材料具有正交结构、单轴取向和纳米晶粒尺寸。该负极材料在锂离子电池中具有良好的电化学性能，包括高容量保持率和库仑效率、良好的可循环性、低电荷转移率、高Li+扩散系数和优异的倍率性能。在0.1 A g-1的电流密度下，经过120次循环后，它们的可逆容量为437 mAh g-1，即使在10 A g-1的高电流密度下，充电容量也达到299 mAh g-1。优异的性能可归因于独特的纳米结构钙钛矿。纳米材料提供了更大的电极/电解质界面，减少了锂离子的扩散长度，改善了反应动力学。钙钛矿结构有效地防止了循环过程中阳极的降解，表现出优异的可逆存储。对电化学反应动力学进行了研究。这些都表明了HoFeO3钙钛矿作为锂离子电池负极材料的巨大潜力。
{"title":"Fabricating Nanostructured HoFeO 3 Perovskite for Lithium-Ion Battery Anodes via Co-Precipitation","authors":"A. T. Nguyen, V. Phung, V. Mittova, H. Ngo, Thuan Ngoc Vo, My Linh Le Thi, V. Nguyen, I. Mittova, M. Le, Y. Ahn, I. Kim, Tuan Loi Nguyen","doi":"10.2139/ssrn.3882746","DOIUrl":"https://doi.org/10.2139/ssrn.3882746","url":null,"abstract":"Nanostructured HoFeO3 perovskite was successfully prepared via co-precipitation of Fe3+ and Ho3+ ions in ethanol, followed by heat treatment. Analysis revealed the orthorhombic structure, uniaxial orientation, and nanograin size. This anode material exhibited excellent electrochemical properties in lithium-ion batteries including high capacity retention and Coulombic efficiency, good cyclability, low charge transfer, high Li+ diffusion coefficient, and excellent rate performance. They delivered reversible capacity of 437 mAh g-1 after 120 cycles at current density of 0.1 A g-1, a charge capacity of 299 mAh g-1 even at high current density of 10 A g-1. Outstanding performance can be ascribed to unique nanostructured perovskite. Nanosized materials offer a larger electrode/electrolyte interface, and reduce Li-ion diffusion length, improving reaction kinetics. Perovskite structure effectively prevented anode degradation during cycling, demonstrating excellent reversible storage. Kinetics of electrochemical reactions were also studied. All indicate the great potential of HoFeO3 perovskite as an anode material in LIBs.","PeriodicalId":412570,"journal":{"name":"Electrochemistry eJournal","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122822576","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}
F17A protein, the major subunit of F17 fimbriae, is one of the most prevalent and crucial virulence factors among the pathogenic Escherichia coli ( E. coli ) isolated from diarrheic and septicemic animals of various species. Purification and detection of this protein is regarded as an interesting field of investigation due to its important role as a therapeutic target, such as vaccines, and as a diagnostic tool. In this context, polyclonal rabbit antibodies recognizing F17A protein were developed and validated by indirect enzyme-linked immunosorbent assay and Western blot. Moreover, sandwich biosensor using anti−F17A/gold nanoparticles conjugate as capture probe and anti−F17A antibody labelled with horseradish peroxidase (HRP) as signal amplification probe was developed for electrochemical and fluorescent detection of purified F17A protein and live E. coli bacteria positive for F17. Good specificity and sensitivity for detection of E. coli strains positive for F17 were obtained with a lower detection limit of 37 CFU/mL.
{"title":"Sandwich−Based Immunosensor for Electrochemical and Fluorescent Detection of F17-Positive Escherichia Coli and its F17A Fimbrial Protein","authors":"Imed Salhi, Amal Rabti, Asma Dhehibi, N. Raouafi","doi":"10.2139/ssrn.3929281","DOIUrl":"https://doi.org/10.2139/ssrn.3929281","url":null,"abstract":"F17A protein, the major subunit of F17 fimbriae, is one of the most prevalent and crucial virulence factors among the pathogenic Escherichia coli ( E. coli ) isolated from diarrheic and septicemic animals of various species. Purification and detection of this protein is regarded as an interesting field of investigation due to its important role as a therapeutic target, such as vaccines, and as a diagnostic tool. In this context, polyclonal rabbit antibodies recognizing F17A protein were developed and validated by indirect enzyme-linked immunosorbent assay and Western blot. Moreover, sandwich biosensor using anti−F17A/gold nanoparticles conjugate as capture probe and anti−F17A antibody labelled with horseradish peroxidase (HRP) as signal amplification probe was developed for electrochemical and fluorescent detection of purified F17A protein and live E. coli bacteria positive for F17. Good specificity and sensitivity for detection of E. coli strains positive for F17 were obtained with a lower detection limit of 37 CFU/mL.","PeriodicalId":412570,"journal":{"name":"Electrochemistry eJournal","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121965254","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}
Electrodeposited Ni-Fe alloys are expected to have an improved mechanical strength because of their nanocrystalline structure. However, unsatisfactory grain refinement yields a higher coercivity compared with conventional permalloys, which is undesirable in soft magnetic materials. We report electrodeposited Ni-Fe-P alloys that combine the mechanical properties of nanocrystalline materials with soft magnetism that is achievable in coarse-grained permalloys. Up to 2.0 at% P, the resultant Ni-Fe-P alloys achieved a tensile strength of 2.1 GPa, along with a plastic deformability. The electrodeposited alloys exhibited a saturation magnetic flux density of 1.1 T and a coercivity of 8.4 A/m. Our approach indicates that graine refinement by the P alloying can result in a lower coercivity, according to the law of the grain size and coercivity.
电沉积镍铁合金由于其纳米晶结构，有望提高其机械强度。然而，与传统的坡莫合金相比，不理想的晶粒细化产生了更高的矫顽力，这在软磁材料中是不希望的。我们报道了电沉积的Ni-Fe-P合金，它结合了纳米晶材料的机械性能和软磁性，这在粗粒度的坡莫合金中是可以实现的。当P含量达到2.0时，Ni-Fe-P合金的抗拉强度达到2.1 GPa，并具有塑性变形能力。电沉积合金的饱和磁通密度为1.1 T，矫顽力为8.4 a /m。我们的方法表明，根据晶粒尺寸和矫顽力的规律，P合金的晶粒细化可以导致较低的矫顽力。
{"title":"Electrodeposition of Bulk Nanocrystalline Ni-Fe-P Alloys and Their Mechanical and Soft Magnetic Properties","authors":"I. Matsui, N. Omura","doi":"10.2139/ssrn.3563938","DOIUrl":"https://doi.org/10.2139/ssrn.3563938","url":null,"abstract":"Electrodeposited Ni-Fe alloys are expected to have an improved mechanical strength because of their nanocrystalline structure. However, unsatisfactory grain refinement yields a higher coercivity compared with conventional permalloys, which is undesirable in soft magnetic materials. We report electrodeposited Ni-Fe-P alloys that combine the mechanical properties of nanocrystalline materials with soft magnetism that is achievable in coarse-grained permalloys. Up to 2.0 at% P, the resultant Ni-Fe-P alloys achieved a tensile strength of 2.1 GPa, along with a plastic deformability. The electrodeposited alloys exhibited a saturation magnetic flux density of 1.1 T and a coercivity of 8.4 A/m. Our approach indicates that graine refinement by the P alloying can result in a lower coercivity, according to the law of the grain size and coercivity.","PeriodicalId":412570,"journal":{"name":"Electrochemistry eJournal","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115007251","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}
N-doped carbon materials have been considered as one of the most promising options for the replacement of platinum-based electrocatalysts towards the oxygen reduction reaction. However, what is known about this kind of catalysts and the identification of the active sites is still contradictory. Most of the scientific literature focuses on experimental characterization before ORR testing, leading to a consistent lack of knowledge about the surface chemistry at operando conditions. The development of operando techniques is, up to now, not enough to unravel with accuracy the reasons why these catalysts are as active as platinum-based electrodes and to understand the deactivation with time of use. In this work, the changes occurring in the active sites of N-doped carbon catalysts have been analysed in detail through pre- and post-ORR extended characterization of selectively N-doped carbon materials, along with sophisticated computational modelling.
{"title":"On the Pathways of N-Doped Carbon Materials Active Sites During Oxygen Reduction Reaction","authors":"J. Quílez‐Bermejo, E. Morallón, D. Cazorla-Amorós","doi":"10.2139/ssrn.3926130","DOIUrl":"https://doi.org/10.2139/ssrn.3926130","url":null,"abstract":"N-doped carbon materials have been considered as one of the most promising options for the replacement of platinum-based electrocatalysts towards the oxygen reduction reaction. However, what is known about this kind of catalysts and the identification of the active sites is still contradictory. Most of the scientific literature focuses on experimental characterization before ORR testing, leading to a consistent lack of knowledge about the surface chemistry at operando conditions. The development of operando techniques is, up to now, not enough to unravel with accuracy the reasons why these catalysts are as active as platinum-based electrodes and to understand the deactivation with time of use. In this work, the changes occurring in the active sites of N-doped carbon catalysts have been analysed in detail through pre- and post-ORR extended characterization of selectively N-doped carbon materials, along with sophisticated computational modelling.","PeriodicalId":412570,"journal":{"name":"Electrochemistry eJournal","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132023794","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 electrochemical reaction of 4-ethynylaniline ( 4-EA ) in the present of sodium azide in buffered solutions with the various pHs (buffer solution /acetonitrile (80/20 v/v)) was investigated for the first time. Our electrochemical data assert that the product of oxidation of 4-ethynylaniline enter in the chemical reaction with azide ion. In continues, after the 1,3 dipolar cycloaddition, electrochemical oxidation, dimerization and third step electrochemical oxidation a triazole ring was produced as a desired product in a simple undivided cell and using carbon anode. The critical aim in this study was applying a non-catalytic procedure for the synthesis of triazole ring in the room temperature that successfully achieved.
{"title":"Electrochemical Oxidation Assisted with the 1,3-Dipolar Cycloaddition for the Synthesis of the New Substituted Triazole","authors":"Sadegh Khazalpour, Maryam Mehrdadian, A. Amani","doi":"10.2139/ssrn.3932110","DOIUrl":"https://doi.org/10.2139/ssrn.3932110","url":null,"abstract":"The electrochemical reaction of 4-ethynylaniline ( 4-EA ) in the present of sodium azide in buffered solutions with the various pHs (buffer solution /acetonitrile (80/20 v/v)) was investigated for the first time. Our electrochemical data assert that the product of oxidation of 4-ethynylaniline enter in the chemical reaction with azide ion. In continues, after the 1,3 dipolar cycloaddition, electrochemical oxidation, dimerization and third step electrochemical oxidation a triazole ring was produced as a desired product in a simple undivided cell and using carbon anode. The critical aim in this study was applying a non-catalytic procedure for the synthesis of triazole ring in the room temperature that successfully achieved.","PeriodicalId":412570,"journal":{"name":"Electrochemistry eJournal","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132347531","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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