Journal articles: 'High entropy oxide'

1

Bridges, Craig A., Bishnu Prasad Thapaliya, Albina Borisevich, Juntian Fan, and Sheng Dai. "(Invited) High Entropy Multication Oxide Battery Materials." ECS Meeting Abstracts MA2022-02, no. 1 (October 9, 2022): 29. http://dx.doi.org/10.1149/ma2022-02129mtgabs.

Full text

Abstract:

High entropy oxides (HEOs), in which multication occupation of a single crystallographic site plays an important role in the properties, have become relevant in energy storage [1,2], catalysis [3.4], and many more areas. In a subset of these compounds the entropy, rather than enthalpy, plays a dominant role in stabilizing a single-phase structure at high temperatures. In other cases, the multication occupation merely contributes to stability and properties, but the entropy remains dominant in the stability. The field originated with high entropy metal alloys (HEAs)[5], and then expanded to oxides, borides, sulfides, and more. In the case of HEOs, the first example is the rock salt (Mg0.2Ni0.2Co0.2Cu0.2Zn0.2)O, which has generated a great deal of interest in this class of materials.[6,7] It has been shown that HEOs are of interest for high ionic conductivity and electrochemical energy storage. We have examined the electrochemical performance of new high entropy elecrolytes and found an effect of composition on the cycling performance. Samples were prepared through sol-gel routes and high energy milling of starting binary oxides. We have investigated the synthesis using high temperature in-situ X-ray diffraction on a Panalytical diffractometer equipped with an XRK900 stage. STEM/EDS studies on ex-situ samples will be presented that show elemental distribution, with Raman and EIS measurements providing information on ionic diffusion. The results of this study will be highly impactful for the growing community of researchers investigating the design and synthesis of the new class of materials, the high entropy oxides. [1] Q. Wang, et. al., Multi-anionic and -cationic compounds: new high entropy materials for advanced Li-ion batteries, Energy Environ. Sci., 2019, 12, 2433; [2] D. Berardan, et. al., Room temperature lithium superionic conductivity in high entropy oxides, J. Mater. Chem. A, 2016, 4, 9536.; [3] H. Chen, et al., Mechanochemical Synthesis of High Entropy Oxide Materials under Ambient Conditions: Dispersion of Catalysts via Entropy Maximization, ACS Materials Lett. 2019, 1, 1, 83–88; [4] H. Chen, et. al., Entropy-stabilized metal oxide solid solutions as CO oxidation catalysts with high-temperature stability, J. Mater. Chem. A 2018, 6, 11129-11133; [5] Y. Lu, et. al., Sci. Rep. 4, 6200 (2014); Y. F. Ye, et. al., Mater. Today 19 (6), 349 (2016); Zhang, Y., et. al., Nature Commun. 6, 8736 (2015); [6] C. M. Rost, et. al., Nature Commun. 6, 8485 (2015); [7] B. Jiang, et. al., Probing the Local Site Disorder and Distortion in Pyrochlore High-Entropy Oxides. Journal of the American Chemical Society 2021, 143, (11), 4193-4204

APA, Harvard, Vancouver, ISO, and other styles

2

Meisenheimer, P. B., and J. T. Heron. "Oxides and the high entropy regime: A new mix for engineering physical properties." MRS Advances 5, no. 64 (2020): 3419–36. http://dx.doi.org/10.1557/adv.2020.295.

Full text

Abstract:

AbstractHistorically, the enthalpy is the criterion for oxide materials discovery and design. In this regime, highly controlled thin film epitaxy can be leveraged to manifest bulk and interfacial phases that are non-existent in bulk equilibrium phase diagrams. With the recent discovery of entropy-stabilized oxides, entropy and disorder engineering has been realized as an orthogonal approach. This has led to the nucleation and rapid growth of research on high-entropy oxides – multicomponent oxides where the configurational entropy is large but its contribution to its stabilization need not be significant or is currently unknown. From current research, it is clear that entropy enhances the chemical solubility of species and can realize new stereochemical configurations which has led to the rapid discovery of new phases and compositions. The research has expanded beyond studies to understand the role of entropy in stabilization and realization of new crystal structures to now include physical properties and the roles of local and global disorder. Here, key observations made regarding the dielectric and magnetic properties are reviewed. These materials have recently been observed to display concerted symmetry breaking, metal-insulator transitions, and magnetism, paving the way for engineering of these and potentially other functional phenomena. Excitingly, the disorder in these oxides allows for new interplay between spin, orbital, charge, and lattice degrees of freedom to design the physical behavior. We also provide a perspective on the state of the field and prospects for entropic oxide materials in applications considering their unique characteristics.

APA, Harvard, Vancouver, ISO, and other styles

3

Oh, Seeun, Dongyeon Kim, and Kang Taek Lee. "High Entropy Perovskite Electrolytes for Reversible Protonic Ceramic Electrochemical Cells." ECS Transactions 111, no. 6 (May 19, 2023): 1743–49. http://dx.doi.org/10.1149/11106.1743ecst.

Full text

Abstract:

Reversible protonic ceramic electrochemical cells (R-PCECs) have become the cornerstone of low-temperature solid oxide electrochemical cells (SOCs) below 600 °C. Low activation energy and high energy conversion efficiency are primary significance of R-PCECs. However, electrolytes of high-performance R-PCECs still suffer from poor tolerance to complex operating conditions. To overcome their low stability and enhance proton conductivity, various cations have been doped into the Ba-based perovskite oxide electrolyte. Developing high entropy oxides by introducing multiple metal cations into A- or B- sites of the perovskite structure can be an effective solution for the structural stability. Due to the effect of the entropy-dominated stabilization in multi-doped perovskite oxides, the material can remain single phase under extreme temperatures and chemical environments. Promising high entropy stabilization concepts were adapted to electrolytes, and finally, durable proton-conducting perovskite oxide was designed. Here, we will present our recent progress on development of high entropy perovskite oxide electrolytes for R-PCECs.

APA, Harvard, Vancouver, ISO, and other styles

4

Li, Haoyang, Yue Zhou, Zhihao Liang, Honglong Ning, Xiao Fu, Zhuohui Xu, Tian Qiu, Wei Xu, Rihui Yao, and Junbiao Peng. "High-Entropy Oxides: Advanced Research on Electrical Properties." Coatings 11, no. 6 (May 24, 2021): 628. http://dx.doi.org/10.3390/coatings11060628.

Full text

Abstract:

The concept of “high entropy” was first proposed while exploring the unknown center of the metal alloy phase diagram, and then expanded to oxides. The colossal dielectric constant found on the bulk high-entropy oxides (HEOs) reveals the potential application of the high-entropy oxides in the dielectric aspects. Despite the fact that known HEO thin films have not been reported in the field of dielectric properties so far, with the high-entropy effects and theoretical guidance of high entropy, it is predictable that they will be discovered. Currently, researchers are verifying that appropriately increasing the oxygen content in the oxide, raising the temperature and raising the pressure during preparation have an obvious influence on thin films’ resistivity, which may be the guidance on obtaining an HEO film large dielectric constant. Finally, it could composite a metal–insulator–metal capacitor, and contribute to sensors and energy storage devices’ development; alternatively, it could be put into application in emerging thin-film transistor technologies, such as those based on amorphous metal oxide semiconductors, semiconducting carbon nanotubes, and organic semiconductors.

APA, Harvard, Vancouver, ISO, and other styles

5

Sharma, Yogesh, Min-Cheol Lee, Krishna Chaitanya Pitike, Karuna K. Mishra, Qiang Zheng, Xiang Gao, Brianna L. Musico, et al. "High Entropy Oxide Relaxor Ferroelectrics." ACS Applied Materials & Interfaces 14, no. 9 (February 28, 2022): 11962–70. http://dx.doi.org/10.1021/acsami.2c00340.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Kajitani, Tsuyoshi, Yuzuru Miyazaki, Kei Hayashi, Kunio Yubuta, X. Y. Huang, and W. Koshibae. "Thermoelectric Energy Conversion and Ceramic Thermoelectrics." Materials Science Forum 671 (January 2011): 1–20. http://dx.doi.org/10.4028/www.scientific.net/msf.671.1.

Full text

Abstract:

Oxide thermoelectrics are relatively new materials that are workable at temperatures in the range of 400K≤T≤1200K. There are several types of thermoelectric oxide, namely, cobalt oxides (p-type semi-conductors), manganese oxides (n-type) and zinc oxides (n-type semi-conductors) for high temperature energy harvesting. The Seebeck coefficient of 3d metal oxide thermoelectrics is relatively high due to either high density of states at Fermi surfaces or spin entropy flow associated with the carrier flow. The spin entropy part dominates the Seebeck coefficient of 3d-metal oxides at temperatures above 300K. Introduction of impurity particles or quantum-well structures to enhance thermionic emission and energy filtering effects for the oxide semiconductors may lead to a significant improvement of thermoelectric performance.

APA, Harvard, Vancouver, ISO, and other styles

7

Tanveer, Rubayet, and Veerle M. Keppens. "Resonant ultrasound spectroscopy studies of high-entropy fluorites." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A131. http://dx.doi.org/10.1121/10.0015786.

Full text

Abstract:

High entropy oxides (HEOs), also referred to as multicomponent oxides or compositionally complex oxides (CCOs), have attracted attention due to the tunability of multiple cations on a single site. Since the introduction of HEOs stabilized in the rocksalt phase, the high entropy oxide concept has been expanded to various structures, offering a path for the discovery of innovative compounds with unique structure-property relations. Here, we present a study of high entropy fluorites, which have gained recognition for their low thermal conductivity and possible applications as thermal barrier coatings. We have successfully synthesized single phase samples using multiple cations on a single site, in equimolar and non-equimolar ratios. Resonant ultrasound spectroscopy was used to evaluate the elastic moduli as a function of temperature. The results obtained on these multi-component pyrochlores are compared to those of their single-component counterparts.

APA, Harvard, Vancouver, ISO, and other styles

8

Wang, Junfeng, Qiaobai He, Guanqi Liu, Qi Zhang, Guotan Liu, Zhihao Huang, Xiaoshuo Zhu, and Yudong Fu. "High-Temperature Oxidation Behavior of AlTiNiCuCox High-Entropy Alloys." Materials 14, no. 18 (September 15, 2021): 5319. http://dx.doi.org/10.3390/ma14185319.

Full text

Abstract:

In this study, the high-temperature oxidation behavior of a series of AlTiNiCuCox high-entropy alloys (HEAs) was explored. The AlTiNiCuCox (x = 0.5, 0.75, 1.0, 1.25, 1.5) series HEAs were prepared using a vacuum induction melting furnace, in which three kinds of AlTiNiCuCox (x = 0.5, 1.0, 1.5) alloys with different Co contents were oxidized at 800 °C for 100 h, and their oxidation kinetic curves were determined. The microstructure, morphology, structure, and phase composition of the oxide film surface and cross-sectional layers of AlTiNiCuCox series HEAs were analyzed using scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD). The influence of Co content on the high-temperature oxidation resistance of the HEAs was discussed, and the oxidation mechanism was summarized. The results indicate that, at 800 °C, the AlTiNiCuCox (x = 0.5, 1.0, 1.5) series HEAs had dense oxide films and certain high-temperature oxidation resistance. With increasing Co content, the high-temperature oxidation resistance of the alloys also increased. With increasing time at high temperature, there was a significant increase in the contents of oxide species and Ti on the oxide film surface. In the process of high-temperature oxidation of AlTiNiCuCox series HEAs, the interfacial reaction, in which metal elements and oxygen in the alloy form ions through direct contact reaction, initially dominated, then the diffusion process gradually became the dominant oxidation factor as ions diffused and were transported in the oxide film.

APA, Harvard, Vancouver, ISO, and other styles

9

Hashishin, Takeshi, Haruka Taniguchi, Fei Li, and Hiroya Abe. "Useful High-Entropy Source on Spinel Oxides for Gas Detection." Sensors 22, no. 11 (June 1, 2022): 4233. http://dx.doi.org/10.3390/s22114233.

Full text

Abstract:

This study aimed to identify a useful high-entropy source for gas detection by spinel oxides that are composed of five cations in nearly equal molar amounts and free of impurities. The sensor responses of the spinel oxides [1# (CoCrFeMnNi)3O4, 2# (CoCrFeMnZn)3O4, 3# (CoCrFeNiZn)3O4, 4# (CoCrMnNiZn)3O4, 5# (CoFeMnNiZn)3O4, and 6# (CrFeMnNiZn)3O4] were evaluated for the test gases (7 ppm NO2, 5000 ppm H2, 3 ppm NH3, and 3 ppm H2S). In response to NO2, 1# and 2# showed p-type behavior while 3–6# showed n-type semiconductor behavior. There are three p-type and one n-type AO structural compositions in AB2O4[AO·B2O3] type spinel, and 1# showed a stable AO composition because cation migration from site B to site A is unlikely. Therefore, it was assumed that 1# exhibited p-type behavior. The p-type behavior of 2# was influenced by Cr oxide ions that were present at the B site and the stable p-type behavior of zinc oxide at the A site. The spinel oxides 3# to 6# exhibited n-type behavior with the other cationic oxides rather than the dominant p-type behavior exhibited by the Zn oxide ions that are stable at the A site. In contrast, the sensor response to the reducing gases H2, NH3, and H2S showed p-type semiconductor behavior, with a particularly selective response to H2S. The sensor responses of the five-element spinel oxides in this study tended to be higher than that of the two-element Ni ferrites and three-element Ni-Zn ferrites reported previously. Additionally, the susceptibility to sulfurization was evaluated using the thermodynamic equilibrium theory for the AO and B2O3 compositions. The oxides of Cr, Fe, and Mn ions in the B2O3 composition did not respond to H2S because they were not sulfurized. The increase in the sensor response due to sulfurization was attributed to the decrease in the depletion layer owing to electron sensitization, as the top surface of the p-type semiconductors, ZnO and NiO, transformed to n-type semiconductors, ZnS and NiS, respectively. High-entropy oxides prepared using the hydrothermal method with an equimolar combination of five cations from six elements (Cr, Mn, Fe, Co, Ni, and Zn) can be used as a guideline for the design of high-sensitivity spinel-type composite oxide gas sensors.

APA, Harvard, Vancouver, ISO, and other styles

10

Ke, Lingsheng, Long Meng, Sheng Fang, Chun Lin, Mingtian Tan, and Tao Qi. "High-Temperature Oxidation Behaviors of AlCrTiSi0.2 High-Entropy Alloy Doped with Rare Earth La and Y." Crystals 13, no. 8 (July 27, 2023): 1169. http://dx.doi.org/10.3390/cryst13081169.

Full text

Abstract:

High-entropy alloys (HEAs) were prepared with strong antioxidant metals Al, Cr, Ti, and Si as matrix elements, and the effects of rare earth (RE) lanthanum (La) and yttrium (Y) doping on their microstructures and high-temperature oxidation resistance were explored in this study. The AlCrTiSi0.2RE0.02 HEAs were prepared by using vacuum arc melting and were oxidized mass gain at 1000 °C. After oxidation for 53 h, AlCrTiSi0.2 HEA had a mass increase of 1.195 mg/cm2, and it had the best oxidation resistance of three HEAs (AlCrTiSi0.2, AlCrTiSi0.2La0.02, and AlCrTiSi0.2Y0.02). The surface oxide layers of three HEAs mainly consisted of Al and Ti oxides; the layered oxide film of AlCrTiSi0.2 alloy was mainly composed of dense Al2O3, and the acicular oxide films of AlCrTiSi0.2La0.02 and AlCrTiSi0.2Y0.02 alloys were primarily composed of loose Ti oxide. Doping La and Y decreased the oxidation resistance of AlCrTiSi0.2. In the early stage of oxidation of rare earth HEAs, the surface oxide layer was loose because La and Y reacted with the matrix metal, which slowed down the diffusion of element Al or accelerated the diffusion of element Ti. In the late stage of oxidation, La and Y interacted with O and entered the matrix metal to form rare earth oxides.

APA, Harvard, Vancouver, ISO, and other styles

11

Wang, Lin, Quanqing Zeng, Zhibao Xie, Yun Zhang, and Haitao Gao. "High Temperature Oxidation Behavior of an Equimolar Cr-Mn-Fe-Co High-Entropy Alloy." Materials 14, no. 15 (July 30, 2021): 4259. http://dx.doi.org/10.3390/ma14154259.

Full text

Abstract:

The oxidation behavior of an equimolar Cr-Mn-Fe-Co high-entropy alloy (HEA) processed by 3D laser printing was investigated at 700 °C and 900 °C. The oxidation kinetics of the alloy followed the parabolic rate law, and the oxidation rate constant increased with the rising of the temperature. Inward diffusion of oxygen and outward diffusion of cations took place during the high-temperature oxidation process. A spinel-type oxide was formed on the surface, and the thickness of the oxide layer increased with the rising of experimental temperature or time. The exfoliation of the oxide layer took place when the test was operated at 900 °C over 12 h. During oxidation tests, the matrix was propped open by oxides and was segmented into small pieces. The formation of loose structures had great effects on the high-temperature oxidation resistance of the HEA.

APA, Harvard, Vancouver, ISO, and other styles

12

Dong, Qi, Min Hong, Jinlong Gao, Tangyuan Li, Mingjin Cui, Shuke Li, Haiyu Qiao, et al. "Rapid Synthesis of High‐Entropy Oxide Microparticles." Small 18, no. 11 (January 20, 2022): 2104761. http://dx.doi.org/10.1002/smll.202104761.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Vinnik, Trofimov, Zhivulin, Gudkova, Zaitseva, Zherebtsov, Starikov, et al. "High Entropy Oxide Phases with Perovskite Structure." Nanomaterials 10, no. 2 (February 5, 2020): 268. http://dx.doi.org/10.3390/nano10020268.

Full text

Abstract:

The possibility of the formation of high entropy single-phase perovskites using solid-state sintering was investigated. The BaO–SrO–CaO–MgO–PbO–TiO2, BaO–SrO–CaO–MgO–PbO–Fe2O3 and Na2O–K2O–CaO–La2O3–Ce2O3–TiO2 oxide systems were investigated. The optimal synthesis temperature is found between 1150 and 1400 °C, at which the microcrystalline single phase with perovskite structure was produced. The morphology, chemical composition, crystal parameters and dielectric properties were studied and compared with that of pure BaTiO3. According to the EDX data, the single-phase product has a formula of Na0.30K0.07Ca0.24La0.18Ce0.21TiO3 and a cubic structure.

APA, Harvard, Vancouver, ISO, and other styles

14

Hadraba, Hynek, Zdenek Chlup, Antonin Dlouhy, Ferdinand Dobes, Pavla Roupcova, Monika Vilemova, and Jiri Matejicek. "Oxide dispersion strengthened CoCrFeNiMn high-entropy alloy." Materials Science and Engineering: A 689 (March 2017): 252–56. http://dx.doi.org/10.1016/j.msea.2017.02.068.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Mileiko, S. T., S. A. Firstov, N. A. Novokhatskaya, V. F. Gorban, and N. P. Krapivka. "Oxide-fibre/high-entropy-alloy-matrix composites." Composites Part A: Applied Science and Manufacturing 76 (September 2015): 131–34. http://dx.doi.org/10.1016/j.compositesa.2015.05.023.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Vinnik, D. A., E. A. Trofimov, V. E. Zhivulin, O. V. Zaitseva, S. A. Gudkova, A. Yu Starikov, D. A. Zherebtsov, A. A. Kirsanova, M. Häßner, and R. Niewa. "High-entropy oxide phases with magnetoplumbite structure." Ceramics International 45, no. 10 (July 2019): 12942–48. http://dx.doi.org/10.1016/j.ceramint.2019.03.221.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

CAYIRLI, Meltem, Esra ERDOGAN-ESEN, Ersu LOKCU, and Mustafa ANIK. "Synthesis and Electrochemical Performance of Spinel Crystal Structured ((FeNiCrMn)1-xCox)3O4 (x=0.1, 0.2, 0.3) High Entropy Oxides." Eurasia Proceedings of Science Technology Engineering and Mathematics 16 (December 31, 2021): 140–44. http://dx.doi.org/10.55549/epstem.1068579.

Full text

Abstract:

High entropy oxides are a new class of materials with a single-phase structure consisting of five or more components. Due to their high structural stability and electrochemical performance, they have attracted a lot of attention in recent years. In this study, high entropy oxides with the composition ((FeNiCrMn)1-xCox)3O4 (x=0.1, 0.2, 0.3) were synthesized using the solid state method and their electrochemical performances as anode material for lithium-ion battery were investigated. Spinel crystal structured of high entropy oxides were characterized by X-ray diffraction (XRD) technique. The electrochemical performance of anodes were evaluated by assembling CR2016 type coin cell. As a result of galvanostatic charge/discharge experiments the initial discharge capacities of ((FeNiCrMn)1-xCox)3O4 (x=0.1, 0.2, 0.3) anodes at a current density of 50 mA g-1 werecalculated as 1993 mA h g-1, 1651 mA h g-1 and 1706 mA h g-1, respectively. Among the synthesized high entropy oxide anodes, the ((FeNiCrMn)0.9Co0.1)3O4 anode shows high initial discharge capacity, while their capacity retention rates at the end of 10th cycle were calculated as 53.9%, 55.1%, 59.7%. This study clearly indicates that the electrochemical performances of high entropy oxide anodes are affected by the Co content.

APA, Harvard, Vancouver, ISO, and other styles

18

Xu, Yangsen, Xi Xu, and Lei Bi. "A high-entropy spinel ceramic oxide as the cathode for proton-conducting solid oxide fuel cells." Journal of Advanced Ceramics 11, no. 5 (April 20, 2022): 794–804. http://dx.doi.org/10.1007/s40145-022-0573-7.

Full text

Abstract:

AbstractA high-entropy ceramic oxide is used as the cathode for the first time for proton-conducting solid oxide fuel cells (H-SOFCs). The Fe0.6Mn0.6Co0.6Ni0.6Cr0.6O4 (FMCNC) high-entropy spinel oxide has been successfully prepared, and the in situ chemical stability test demonstrates that the FMCNC material has good stability against CO2. The first-principles calculation indicates that the high-entropy structure enhances the properties of the FMCNC material that surpasses their individual components, leading to lower O2 adsorption energy for FMCNC than that for the individual components. The H-SOFC using the FMCNC cathode reaches an encouraging peak power density (PPD) of 1052 mW·cm−2 at 700 °C, which is higher than those of the H-SOFCs reported recently. Additional comparison was made between the high-entropy FMCNC cathode and the traditional Mn1.6Cu1.4O4 (MCO) spinel cathode without the high-entropy structure, revealing that the formation of the high-entropy material allows the enhanced protonation ability as well as the movement of the O p-band center closer to the Fermi level, thus improving the cathode catalytic activity. As a result, the high-entropy FMCNC has a much-decreased polarization resistance of 0.057 Ω·cm2 at 700 °C, which is half of that for the traditional MCO spinel cathode without the high-entropy design. The excellent performance of the FMCNC cell indicates that the high-entropy design makes a new life for the spinel oxide as the cathode for H-SOFCs, offering a novel and promising route for the development of high-performance materials for H-SOFCs.

APA, Harvard, Vancouver, ISO, and other styles

19

Leong, Zhaoyuan, Pratik Desai, and Nicola Morley. "Can Empirical Biplots Predict High Entropy Oxide Phases?" Journal of Composites Science 5, no. 12 (November 26, 2021): 311. http://dx.doi.org/10.3390/jcs5120311.

Full text

Abstract:

High entropy oxides are entropy-stabilised oxides that adopt specific disordered structures due to entropy stabilisation. They are a new class of materials that utilises the high-entropy concept first discovered in metallic alloys. They can have interesting properties due to the interactions at the electronic level and can be combined with other materials to make composite structures. The design of new meta-materials that utilise this concept to solve real-world problems may be a possibility but further understanding of how their phase stabilisation is required. In this work, biplots of the composition’s mean electronegativity are plotted against the electron-per-atom ratio of the compounds. The test dataset accuracy in the resulting biplots improves from 78% to 100% when using atomic-number-per-atom Z/a ratios as a biplot parameter. Phase stability maps were constructed using a Voronoi tessellation. This can be of use in determining stability at composite material interfaces.

APA, Harvard, Vancouver, ISO, and other styles

20

Bérardan, D., S. Franger, A. K. Meena, and N. Dragoe. "Room temperature lithium superionic conductivity in high entropy oxides." Journal of Materials Chemistry A 4, no. 24 (2016): 9536–41. http://dx.doi.org/10.1039/c6ta03249d.

Full text

Abstract:

Impedance spectroscopy measurements evidence superionic Li⁺ mobility (>10⁻³ S cm⁻¹) at room temperature and fast ionic mobility for Na⁺ (5 × 10⁻⁶ S cm⁻¹) in high entropy oxides, a new family of oxide-based materials with the general formula (MgCoNiCuZn)_1−x−yGa_yA_xO (with A = Li, Na, K).

APA, Harvard, Vancouver, ISO, and other styles

21

Deng, Chang, Peiwen Wu, Linhua Zhu, Jing He, DuanJian Tao, Linjie Lu, Minqiang He, Mingqing Hua, Huaming Li, and Wenshuai Zhu. "High-entropy oxide stabilized molybdenum oxide via high temperature for deep oxidative desulfurization." Applied Materials Today 20 (September 2020): 100680. http://dx.doi.org/10.1016/j.apmt.2020.100680.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Edalati, Parisa, Qing Wang, Hadi Razavi-Khosroshahi, Masayoshi Fuji, Tatsumi Ishihara, and Kaveh Edalati. "Photocatalytic hydrogen evolution on a high-entropy oxide." Journal of Materials Chemistry A 8, no. 7 (2020): 3814–21. http://dx.doi.org/10.1039/c9ta12846h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Roy, Indranil, Pratik K. Ray, and Ganesh Balasubramanian. "Modeling Oxidation of AlCoCrFeNi High-Entropy Alloy Using Stochastic Cellular Automata." Entropy 24, no. 9 (September 8, 2022): 1263. http://dx.doi.org/10.3390/e24091263.

Full text

Abstract:

Together with the thermodynamics and kinetics, the complex microstructure of high-entropy alloys (HEAs) exerts a significant influence on the associated oxidation mechanisms in these concentrated solid solutions. To describe the surface oxidation in AlCoCrFeNi HEA, we employed a stochastic cellular automata model that replicates the mesoscale structures that form. The model benefits from diffusion coefficients of the principal elements through the native oxides predicted by using molecular simulations. Through our examination of the oxidation behavior as a function of the alloy composition, we corroborated that the oxide scale growth is a function of the complex chemistry and resultant microstructures. The effect of heat treatment on these alloys is also simulated by using reconstructed experimental micrographs. When they are in a single-crystal structure, no segregation is noted for α-Al2O3 and Cr2O3, which are the primary scale-forming oxides. However, a coexistent separation between Al2O3 and Cr2O3 oxide scales with the Al-Ni- and Cr-Fe-rich regions is predicted when phase-separated microstructures are incorporated into the model.

APA, Harvard, Vancouver, ISO, and other styles

24

Yurchenko, Nikita, Evgeniya Panina, Sergey Zherebtsov, Gennady Salishchev, and Nikita Stepanov. "Oxidation Behavior of Refractory AlNbTiVZr0.25 High-Entropy Alloy." Materials 11, no. 12 (December 12, 2018): 2526. http://dx.doi.org/10.3390/ma11122526.

Full text

Abstract:

Oxidation behavior of a refractory AlNbTiVZr0.25 high-entropy alloy at 600–900 °C was investigated. At 600–700 °C, two-stage oxidation kinetics was found: Nearly parabolic oxidation (n = 0.46–0.48) at the first stage, transitioned to breakaway oxidation (n = 0.75–0.72) at the second stage. At 800 °C, the oxidation kinetics was nearly linear (n = 0.92) throughout the entire duration of testing. At 900 °C, the specimen disintegrated after 50 h of testing. The specific mass gains were estimated to be 7.2, 38.1, and 107.5, and 225.5 mg/cm2 at 600, 700, and 800 °C for 100 h, and 900 °C for 50 h, respectively. Phase compositions and morphology of the oxide scales were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was shown that the surface layer at 600 °C consisted of the V2O5, VO2, TiO2, Nb2O5, and TiNb2O7 oxides. Meanwhile, the scale at 900 °C comprised of complex TiNb2O7, AlNbO4, and Nb2Zr6O17 oxides. The oxidation mechanisms operating at different temperatures were discussed and a comparison of oxidation characteristics with the other alloys was conducted.

APA, Harvard, Vancouver, ISO, and other styles

25

Guo, Hui-Xia, Wei-Ming Wang, Cheng-Yu He, Bao-Hua Liu, Dong-Mei Yu, Gang Liu, and Xiang-Hu Gao. "Entropy-Assisted High-Entropy Oxide with a Spinel Structure toward High-Temperature Infrared Radiation Materials." ACS Applied Materials & Interfaces 14, no. 1 (December 27, 2021): 1950–60. http://dx.doi.org/10.1021/acsami.1c20055.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Sun, Zheng, Yongjie Zhao, Chen Sun, Qing Ni, Chengzhi Wang, and Haibo Jin. "High entropy spinel-structure oxide for electrochemical application." Chemical Engineering Journal 431 (March 2022): 133448. http://dx.doi.org/10.1016/j.cej.2021.133448.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Phakatkar, Abhijit, Reza Shahbazian-Yassar, and Tolou Shokuhfar. "STEM-EELS Analysis of High Entropy Oxide Nanoparticles." Microscopy and Microanalysis 27, S1 (July 30, 2021): 884–86. http://dx.doi.org/10.1017/s1431927621003421.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Lin, Ling, Kai Wang, Raheleh Azmi, Junbo Wang, Abhishek Sarkar, Miriam Botros, Saleem Najib, et al. "Mechanochemical synthesis: route to novel rock-salt-structured high-entropy oxides and oxyfluorides." Journal of Materials Science 55, no. 36 (September 14, 2020): 16879–89. http://dx.doi.org/10.1007/s10853-020-05183-4.

Full text

Abstract:

Abstract A facile mechanochemical reaction at ambient temperature was successfully applied to synthesize novel single-phase rock-salt-structured high-entropy oxides, containing five, six and seven metal elements in equiatomic amounts. This synthesis approach overcomes the limitations of the commonly known synthesis procedures, which would result in multiple-phase compounds. Redox-sensitive elements, such as Fe2+ and Mn2+, can now be considered. The corresponding single-phase Li-containing high-entropy oxyfluorides were obtained by introducing LiF into the lattice using the same strategy. All materials show single-phase rock-salt structures with lattice parameters depending on the incorporated ion sizes. Solid solution states result in high configurational entropies, and all elements appear homogenously distributed over the whole cationic and anionic sublattice. The straightforward synthesis technique, combined with utilized simple binary oxide precursors, paves the way for a multitude of novel high-entropy oxide and oxyfluoride compounds. The compounds were studied by means of X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy and Mössbauer spectroscopy.

APA, Harvard, Vancouver, ISO, and other styles

29

Csík, D., D. Zalka, K. Saksl, D. Capková, and R. Džunda. "Four-component high entropy spinel oxide as anode material in lithium-ion batteries with excellent cyclability." Journal of Physics: Conference Series 2382, no. 1 (November 1, 2022): 012003. http://dx.doi.org/10.1088/1742-6596/2382/1/012003.

Full text

Abstract:

Nowadays, energy storage technologies are in focus of public interest, especially in the field of the automotive industry. Lithium-ion batteries (LIBs) are evaluated as one of the most advanced energy storage devices because of their high energy density, which can meet rapidly growing energy requirements. Graphite based anode materials in LIBs are reaching their fundamental limits, especially their specific capacities. Recently, it has been demonstrated that high entropy oxides (HEOs) possess promising and unexpected electrochemical properties, such as remarkable reversible capacity and cycle stability due to the high entropy of the system. The highly disordered structure can provide self-healing properties resulting in regeneration of the capacity by applying low current densities. In addition, they can alleviate volume changes during the cycling process, unlike simple oxides. Among the various types of high entropy oxides, spinel-structured HEOs are the most studied because they ensure the three-dimensional transport of lithium ions ensuring high rate capability. Herein, we report a simple method of preparation of high entropy oxide (HEO) with a spinel structure consisting of 4 different elements (Co, Fe, Cr, Ni). The prepared HEO exhibited excellent cycle stability during (116 mAh.g-1) 500 cycles at a current density of 500 mA.g-1, which confirms their usage as anode active materials in lithium-ion batteries.

APA, Harvard, Vancouver, ISO, and other styles

30

Pikalova, Elena Y., Elena G. Kalinina, Nadezhda S. Pikalova, and Elena A. Filonova. "High-Entropy Materials in SOFC Technology: Theoretical Foundations for Their Creation, Features of Synthesis, and Recent Achievements." Materials 15, no. 24 (December 8, 2022): 8783. http://dx.doi.org/10.3390/ma15248783.

Full text

Abstract:

In this review, recent achievements in the application of high-entropy alloys (HEAs) and high-entropy oxides (HEOs) in the technology of solid oxide fuel cells (SOFC) are discussed for the first time. The mechanisms of the stabilization of a high-entropy state in such materials, as well as the effect of structural and charge factors on the stability of the resulting homogeneous solid solution are performed. An introduction to the synthesis methods for HEAs and HEOs is given. The review highlights such advantages of high-entropy materials as high strength and the sluggish diffusion of components, which are promising for the use at the elevated temperatures, which are characteristic of SOFCs. Application of the medium- and high-entropy materials in the hydrocarbon-fueled SOFCs as protective layers for interconnectors and as anode components, caused by their high stability, are covered. High-entropy solid electrolytes are discussed in comparison with traditional electrolyte materials in terms of conductivity. High-entropy oxides are considered as prospective cathodes for SOFCs due to their superior electrochemical activity and long-term stability compared with the conventional perovskites. The present review also determines the prioritizing directions in the future development of high-entropy materials as electrolytes and electrodes for SOFCs operating in the intermediate and low temperature ranges.

APA, Harvard, Vancouver, ISO, and other styles

31

Jiang, Ji Chao, and Xiu Yan Luo. "High Temperature Oxidation Behaviour of AlCuTiFeNiCr High-Entropy Alloy." Advanced Materials Research 652-654 (January 2013): 1115–18. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.1115.

Full text

Abstract:

The oxidation behaviour of AlCuTiFeNiCr high-entropy alloy with was studied at 850 oC in atmosphere. The oxide layer of long-term oxidation behavior were examined using optical, X-ray powder diffraction (XRD) with the aid of scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analysis (EDX). The oxidation kinetics follows a parabolic rate law. The oxidation rate decreases gradually as the oxidation proceeds.

APA, Harvard, Vancouver, ISO, and other styles

32

Shi, Yunzhu, Rui Li, and Zhifeng Lei. "Influences of Synthetic Parameters on Morphology and Growth of High Entropy Oxide Nanotube Arrays." Coatings 13, no. 1 (December 27, 2022): 46. http://dx.doi.org/10.3390/coatings13010046.

Full text

Abstract:

Nanoscale and nanostructured materials have drawn great attention owing to their outstanding and unique properties. Enlightened by the study of “entropy-stabilized oxides”, nanotubes consisting of multi-component mixed metal oxides are developed, which formed on equi-atomic TiZrHfNbTa high-entropy alloy (HEA). However, the growth mechanism and how the oxidation conditions influence the nanotube growth and morphology remains unknown. In the present study, by controlling the anodization parameters (applied voltages and time) and bath compositions (fluoride concentration and water content), scanning electron microscope and transmission electron microscopy are conducted to reveal the morphological evolution. The present work uncovers how the synthetic parameters influence the tube growth and morphology formed on equi-atomic TiZrHfNbTa HEA, therefore gaining insight into the growth mechanism and the feasibility of controlling the morphology of multi-component oxide nanotubes.

APA, Harvard, Vancouver, ISO, and other styles

33

Zaitseva, O. V., D. A. Vinnik, and Evgeny A. Trofimov. "The Poly-Substituted M-Type Hexaferrite Crystals Growth." Materials Science Forum 946 (February 2019): 186–91. http://dx.doi.org/10.4028/www.scientific.net/msf.946.186.

Full text

Abstract:

In the presented article the possibility analysis of highly entropic oxide phases composition and structure formation was performed. Moreover, the studies devoted to the production of substituted single crystals with the M-type hexa-ferrite structure were carried out. The experiments were conducted to studying the possibility of obtaining oxide high-entropy crystalline solid solutions with the M-type hexa-ferrites structure. As the result of the crystallized samples investigation, the microcrystalline highly entropic Ba (Fe,Mn,Ni,Ti,Al)12O19 and (Ba,Pb,Sr)(Fe,Mn,Ti,Ni,Al)12O19 phases appearing was detected. Based on the obtained data, it is possible to consider that the poly-substituted crystals growth with M-type hexa-ferrite structure. The structural stabilization is promoted by high values of the configurational entropy of the crystal matrix components mixing.

APA, Harvard, Vancouver, ISO, and other styles

34

Lo Faro, Massimiliano, and Sebastian Vecino-Mantilla. "High-Entropy Proton Conductive Electrolyte for Intermediate Temperature Operation." ECS Transactions 111, no. 6 (May 19, 2023): 1817–21. http://dx.doi.org/10.1149/11106.1817ecst.

Full text

Abstract:

Due to the high operating temperatures required by commercially available cells, solid oxide electrochemical devices are currently limited in their application to sectors ranging from production to storage of energy, from pollution abatement to pure oxygen distillation. In this study, it is presented a novel electrolyte that promises to dramatically reduce the operating temperature of solid oxide electrochemical devices. Our proposed electrolyte consists of four cations and non-critical raw materials with a stoichiometry that allows for maximum entropy in an ABO3-based oxide. Preliminary results presented in this proceeding indicate that the material outperforms commercial cerates and zirconates in terms of thermal and electrochemical properties, while there is still room for further improvements.

APA, Harvard, Vancouver, ISO, and other styles

35

Liu, Bu-Jine, Tai-Hsin Yin, Yu-Wei Lin, Chun-Wei Chang, Hsin-Chieh Yu, Yongtaek Lim, Hyesung Lee, Changsik Choi, Ming-Kang Tsai, and YongMan Choi. "A Cost-Effective, Nanoporous, High-Entropy Oxide Electrode for Electrocatalytic Water Splitting." Coatings 13, no. 8 (August 19, 2023): 1461. http://dx.doi.org/10.3390/coatings13081461.

Full text

Abstract:

High-entropy materials have attracted extensive attention as emerging electrode materials in various energy applications due to their flexible tunability, unusual outstanding activities, and cost-effectiveness using multiple earth-abundant elements. We introduce a novel high-entropy composite oxide with the five elements of Cu, Ni, Co, Fe, and Cr (HEO-3CNF) for use in the oxygen evolution reaction (OER) in electrocatalytic water splitting. HEO-3CNF is composed of two phases with a non-equimolar, deficient high-entropy spinel oxide of (Cu0.2−xNi0.2Co0.2Fe0.2Cr0.2)3O4 and monoclinic copper oxide (CuO). Electrochemical impedance spectroscopy (EIS) with distribution of relaxation times (DRT) analysis validates that the HEO-3CNF-based electrode exhibits faster charge transfer than benchmark CuO. It results in improved OER performance with a lower overpotential at 10 mA/cm2 and a Tafel slope than CuO (518.1 mV and 119.7 mV/dec versus 615.9 mV and 131.7 mV/dec, respectively) in alkaline conditions. This work may provide a general strategy for preparing novel, cost-effective, high-entropy electrodes for water splitting.

APA, Harvard, Vancouver, ISO, and other styles

36

Tatar, Dalibor, Jelena Kojčinović, Berislav Marković, Aleksandar Széchenyi, Aleksandar Miletić, Sándor Balázs Nagy, Szilveszter Ziegenheim, et al. "Sol-Gel Synthesis of Ceria-Zirconia-Based High-Entropy Oxides as High-Promotion Catalysts for the Synthesis of 1,2-Diketones from Aldehyde." Molecules 26, no. 20 (October 10, 2021): 6115. http://dx.doi.org/10.3390/molecules26206115.

Full text

Abstract:

Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions.

APA, Harvard, Vancouver, ISO, and other styles

37

Akrami, Saeid, Yasushi Murakami, Monotori Watanabe, Tatsumi Ishihara, Makoto Arita, Masayoshi Fuji, and Kaveh Edalati. "Defective high-entropy oxide photocatalyst with high activity for CO2 conversion." Applied Catalysis B: Environmental 303 (April 2022): 120896. http://dx.doi.org/10.1016/j.apcatb.2021.120896.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Zaitseva, O. V., S. A. Gudkova, E. A. Trofimov, V. E. Zhivulin, A. Yu Punda, A. Yu Starikov, and D. A. Vinnik. "New high-entropy oxide phases with the perovskite structure." IOP Conference Series: Materials Science and Engineering 1014, no. 1 (January 1, 2021): 012060. http://dx.doi.org/10.1088/1757-899x/1014/1/012060.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Zhivulin, V. E., E. A. Trofimov, A. Yu Starikov, S. A. Gudkova, A. Yu Punda, D. A. Zherebtsov, O. V. Zaitseva, and D. A. Vinnik. "New high-entropy oxide phases with the magnetoplumbite structure." IOP Conference Series: Materials Science and Engineering 1014, no. 1 (January 1, 2021): 012062. http://dx.doi.org/10.1088/1757-899x/1014/1/012062.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Sure, Jagadeesh, D. Sri Maha Vishnu, and Carsten Schwandt. "Electrochemical conversion of oxide spinels into high-entropy alloy." Journal of Alloys and Compounds 776 (March 2019): 133–41. http://dx.doi.org/10.1016/j.jallcom.2018.10.171.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Wu, Ping Yun, and Jyh-Ming Wu. "Synthesis of High Entropy Oxide through Sol-Gel Method." ECS Meeting Abstracts MA2020-02, no. 29 (November 23, 2020): 1967. http://dx.doi.org/10.1149/ma2020-02291967mtgabs.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Sachkov, V. I., R. A. Nefedov, and I. V. Amelichkin. "High entropy oxide systems based on rare earth elements." IOP Conference Series: Materials Science and Engineering 597 (August 23, 2019): 012005. http://dx.doi.org/10.1088/1757-899x/597/1/012005.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Zhao, Chenglong, Feixiang Ding, Yaxiang Lu, Liquan Chen, and Yong‐Sheng Hu. "High‐Entropy Layered Oxide Cathodes for Sodium‐Ion Batteries." Angewandte Chemie International Edition 59, no. 1 (November 19, 2019): 264–69. http://dx.doi.org/10.1002/anie.201912171.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Zhao, Chenglong, Feixiang Ding, Yaxiang Lu, Liquan Chen, and Yong‐Sheng Hu. "High‐Entropy Layered Oxide Cathodes for Sodium‐Ion Batteries." Angewandte Chemie 132, no. 1 (November 19, 2019): 270–75. http://dx.doi.org/10.1002/ange.201912171.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Nguyen, Thi Xuyen, Jagabandhu Patra, Jeng-Kuei Chang, and Jyh-Ming Ting. "High entropy spinel oxide nanoparticles for superior lithiation–delithiation performance." Journal of Materials Chemistry A 8, no. 36 (2020): 18963–73. http://dx.doi.org/10.1039/d0ta04844e.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Mazza, Alessandro R., Elizabeth Skoropata, Jason Lapano, Michael A. Chilcote, Cameron Jorgensen, Nan Tang, Zheng Gai, et al. "Hole doping in compositionally complex correlated oxide enables tunable exchange biasing." APL Materials 11, no. 3 (March 1, 2023): 031118. http://dx.doi.org/10.1063/5.0142224.

Full text

Abstract:

Magnetic interfaces and the phenomena arising from them drive both the design of modern spintronics and fundamental research. Recently, it was revealed that through designing magnetic frustration in configurationally complex entropy stabilized oxides, exchange bias can occur in structurally single crystal films. This eliminates the need for complex heterostructures and nanocomposites in the design and control of magnetic response phenomena. In this work, we demonstrate through hole doping of a high entropy perovskite oxide that tuning of magnetic responses can be achieved. With detailed magnetometry, we show magnetic coupling exhibiting a variety of magnetic responses including exchange bias and antiferromagnetic spin reversal in the entropy stabilized ABO3 perovskite oxide La1−xSrx(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 family. We find that manipulation of the A-site charge state can be used to balance magnetic phase compositions and coupling responses. This allows for the creation of highly tunable exchange bias responses. In the low Sr doping regime, a spin frustrated region arising at the antiferromagnetic phase boundary is shown to directly couple to the antiferromagnetic moments of the film and emerges as the dominant mechanism, leading to a vertical shift of magnetization loops in response to field biasing. At higher concentrations, direct coupling of antiferromagnetic and ferromagnetic regions is observed. This tunability of magnetic coupling is discussed within the context of these three competing magnetic phases, revealing critical features in designing exchange bias through exploiting spin frustration and disorder in high entropy oxides.

APA, Harvard, Vancouver, ISO, and other styles

47

Yan, Shengxue, Shaohua Luo, Liu Yang, Jian Feng, Pengwei Li, Qing Wang, Yahui Zhang, and Xin Liu. "Novel P2-type layered medium-entropy ceramics oxide as cathode material for sodium-ion batteries." Journal of Advanced Ceramics 11, no. 1 (November 10, 2021): 158–71. http://dx.doi.org/10.1007/s40145-021-0524-8.

Full text

Abstract:

AbstractHigh-entropy oxides (HEOs) and medium-entropy oxides (MEOs) are new types of single-phase solid solution materials. MEOs have rarely been reported as positive electrode material for sodium-ion batteries (SIBs). In this study, we first proposed the concept of the application of MEOs in SIBs. P2-type 3-cation oxide Na2/3Ni1/3Mn1/3Fe1/3O2 (NaNMF) and 4-cation oxide Na2/3Ni1/3Mn1/3Fe1/3−xAlxO2 (NaNMFA) were prepared using the solid-state method, rather than the doping technology. In addition, the importance of the concept of entropy stabilization in material performance and battery cycling was demonstrated by testing 3-cation (NaNMF) and 4-cation (NaNMFA) oxides in the same system. Thus, NaNMFA can provide a reversible capacity of about 125.6 mAh·g−1 in the voltage range of 2–4.2 V, and has enhanced cycle stability. The capacity and decay law of the MEO batteries indicate that the configurational entropy (1.28 R (NaNMFA) > 1.10 R (NaNMF)) of the cationic system, is the main factor affecting the structural and cycle stability of the electrode material. This work emphasizes that the rational design of MEOs with novel structures and different electrochemically active elements may be the strategy for exploring high-performance SIB cathode materials in next-generation energy storage devices.

APA, Harvard, Vancouver, ISO, and other styles

48

Yapryntsev, M. N., I. V. Sudzhanskaya, R. A. Lyubushkin, and E. N. Yapryntseva. "Synthesis and electric transportation properties of high-entropy oxides based on cerium oxide." IOP Conference Series: Materials Science and Engineering 1014, no. 1 (January 1, 2021): 012059. http://dx.doi.org/10.1088/1757-899x/1014/1/012059.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Ayyagari, Sai Venkata Gayathri, Leixin Miao, Matthew Webb, John Heron, and Nasim Alem. "Characterization of High Entropy Oxide Thin Films by High-Resolution STEM-EELS." Microscopy and Microanalysis 29, Supplement_1 (July 22, 2023): 1768–69. http://dx.doi.org/10.1093/micmic/ozad067.916.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Asim, Muhammad, Akbar Hussain, Safia Khan, Javeria Arshad, Tehmeena Maryum Butt, Amina Hana, Mehwish Munawar, et al. "Sol-Gel Synthesized High Entropy Metal Oxides as High-Performance Catalysts for Electrochemical Water Oxidation." Molecules 27, no. 18 (September 13, 2022): 5951. http://dx.doi.org/10.3390/molecules27185951.

Full text

Abstract:

Hexanary high-entropy oxides (HEOs) were synthesized through the mechanochemical sol-gel method for electrocatalytic water oxidation reaction (WOR). As-synthesized catalysts were subjected to characterization, including X-ray diffraction (XRD), Fourier transforms infrared (FTIR) analysis, and scanning electron microscopy (SEM). All the oxide systems exhibited sharp diffraction peaks in XRD patterns indicating the defined crystal structure. Strong absorption between 400–700 cm−1 in FTIR indicated the formation of metal-oxide bonds in all HEO systems. WOR was investigated via cyclic voltammetry using HEOs as electrode platforms, 1M KOH as the basic medium, and 1M methanol (CH3OH) as the facilitator. Voltammetric profiles for both equiatomic (EHEOs) and non-equiatomic (NEHEOs) were investigated, and NEHEOs exhibited the maximum current output for WOR. Moreover, methanol addition improved the current profiles, thus leading to the electrode utility in direct methanol fuel cells as a sequential increase in methanol concentration from 1M to 2M enhanced the OER current density from 61.4 to 94.3 mA cm−2 using NEHEO. The NEHEOs comprising a greater percentage of Al, ([Al0.35(Mg, Fe, Cu, Ni, Co)0.65]3O4) displayed high WOR catalytic performance with the maximum diffusion coefficient, D° (10.90 cm2 s−1) and heterogeneous rate constant, k° (7.98 cm s−1) values. These primary findings from the EC processes for WOR provide the foundation for their applications in high-energy devices. Conclusively, HEOs are proven as novel and efficient catalytic platforms for electrochemical water oxidation.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'High entropy oxide'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles