Discover the SciOpen Platform and Achieve Your Research Goals with Ease.
Search articles, authors, keywords, DOl and etc.
Fluorite-structured oxides constitute an important category of oxides with a wide range of high-temperature applications. Following the concept of high entropy, high-entropy fluorite oxides (HEFOs) have showcased intriguing high-temperature application potential. However, unlocking this potential necessitates an assessment of their long-term stability under high-temperature conditions. In this study, we conducted a prolonged heat treatment at 1000 ℃ on typical HEFO, specifically (CeHfZrGdLa)Ox. After 100 h, high-intensity X-ray diffraction (XRD) revealed a transition from a single-phase fluorite to a multi-phase configuration. Further investigation by analytical electron microscoy (AEM) demonstrated that this degradation resulted from facilitated element diffusion and consequent escalating chemical fluctuation at high temperatures, leading to spontaneous segregation and separation of Ce and La elements, forming Ce-rich, La-poor, and La-rich phases. Notably, the La-rich phase spontaneously transformed from a fluorite structure (space group
Zhang DB, Yu Y, Feng XL, et al. Thermal barrier coatings with high-entropy oxide as a top coat. Ceram Int 2022, 48: 1349–1359.
Clarke DR, Phillpot SR. Thermal barrier coating materials. Mater Today 2005, 8: 22–29.
Liu B, Liu YC, Zhu CH, et al. Advances on strategies for searching for next generation thermal barrier coating materials. J Mater Sci Technol 2019, 35: 833–851.
Cheng FH, Zhang FN, Liu YF, et al. Ti4+-incorporated fluorite-structured high-entropy oxide (Ce,Hf,Y,Pr,Gd)O2− δ : Optimizing preparation and CMAS corrosion behavior. J Adv Ceram 2022, 11: 1801–1814.
Li F, Zhou L, Liu JX, et al. High-entropy pyrochlores with low thermal conductivity for thermal barrier coating materials. J Adv Ceram 2019, 8: 576–582.
Puente-Martínez DE, Díaz-Guillén JA, Montemayor SM, et al. High ionic conductivity in CeO2 SOFC solid electrolytes; effect of Dy doping on their electrical properties. Int J Hydrog Energy 2020, 45: 14062–14070.
Kurumada M, Hara H, Iguchi E. Oxygen vacancies contributing to intragranular electrical conduction of yttria-stabilized zirconia (YSZ) ceramics. Acta Mater 2005, 53: 4839–4846.
Zhang FN, Cheng FH, Cheng CF, et al. Preparation and electrical conductivity of (Zr,Hf,Pr,Y,La)O high entropy fluorite oxides. J Mater Sci Technol 2022, 105: 122–130.
Xu HD, Zhang ZH, Liu JX, et al. Entropy-stabilized single-atom Pd catalysts via high-entropy fluorite oxide supports. Nat Commun 2020, 11: 3908.
Liu HX, Li SQ, Wang WW, et al. Partially sintered copper‒ceria as excellent catalyst for the high-temperature reverse water gas shift reaction. Nat Commun 2022, 13: 867.
Hu LB, Lu B, Xue BW, et al. Production and characterization of highly transparent novel magneto-optical Ho2Zr2O7 ceramics with anion-deficient fluorite structures. J Mater Sci Technol 2023, 150: 217–224.
Gild J, Samiee M, Braun JL, et al. High-entropy fluorite oxides. J Eur Ceram Soc 2018, 38: 3578–3584.
Chen KP, Pei XT, Tang L, et al. A five-component entropy-stabilized fluorite oxide. J Eur Ceram Soc 2018, 38: 4161–4164.
Han Y, Liu XY, Zhang QQ, et al. Ultra-dense dislocations stabilized in high entropy oxide ceramics. Nat Commun 2022, 13: 2871.
Anandkumar M, Lathe A, Palve AM, et al. Single-phase Gd0.2La0.2Ce0.2Hf0.2Zr0.2O2 and Gd0.2La0.2Y0.2Hf0.2Zr0.2O2 nanoparticles as efficient photocatalysts for the reduction of Cr(VI) and degradation of methylene blue dye. J Alloys Compd 2021, 850: 156716.
Zhao ZF, Chen H, Xiang HM, et al. High entropy defective fluorite structured rare-earth niobates and tantalates for thermal barrier applications. J Adv Ceram 2020, 9: 303–311.
Liu DB, Shi BL, Geng LY, et al. High-entropy rare-earth zirconate ceramics with low thermal conductivity for advanced thermal-barrier coatings. J Adv Ceram 2022, 11: 961–973.
Kumbhakar M, Khandelwal A, Jha SK, et al. High-throughput screening of high-entropy fluorite-type oxides as potential candidates for photovoltaic applications. Adv Energy Mater 2023, 13: 2204337.
Xu L, Wang HJ, Su L, et al. A new class of high-entropy fluorite oxides with tunable expansion coefficients, low thermal conductivity and exceptional sintering resistance. J Eur Ceram Soc 2021, 41: 6670–6676.
Wright AJ, Huang CY, Walock MJ, et al. Sand corrosion, thermal expansion, and ablation of medium- and high-entropy compositionally complex fluorite oxides. J Am Ceram Soc 2021, 104: 448–462.
Zhou L, Li F, Liu JX, et al. High-entropy thermal barrier coating of rare-earth zirconate: A case study on (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Zr2O7 prepared by atmospheric plasma spraying. J Eur Ceram Soc 2020, 40: 5731–5739.
Xue Y, Zhao XQ, An YL, et al. High-entropy (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Ce2O7: A potential thermal barrier material with improved thermo-physical properties. J Adv Ceram 2022, 11: 615–628.
Zhang HS, Zhao LM, Sang WW, et al. Thermophysical performances of (La1/6Nd1/6Yb1/6Y1/6Sm1/6Lu1/6)2Ce2O7 high-entropy ceramics for thermal barrier coating applications. Ceram Int 2022, 48: 1512–1521.
Sarkar A, Loho C, Velasco L, et al. Multicomponent equiatomic rare earth oxides with a narrow band gap and associated praseodymium multivalency. Dalton Trans 2017, 46: 12167–12176.
Spiridigliozzi L, Ferone C, Cioffi R, et al. A simple and effective predictor to design novel fluorite-structured high entropy oxides (HEOs). Acta Mater 2021, 202: 181–189.
Spiridigliozzi L, Bortolotti M, Dell’Agli G. On the effect of standard deviation of cationic radii on the transition temperature in fluorite-structured entropy-stabilized oxides (F-ESO). Materials 2023, 16: 2219.
Djenadic R, Sarkar A, Clemens O, et al. Multicomponent equiatomic rare earth oxides. Mater Res Lett 2017, 5: 102–109.
Oses C, Toher C, Curtarolo S. High-entropy ceramics. Nat Rev Mater 2020, 5: 295–309.
Otto F, Dlouhý A, Pradeep KG, et al. Decomposition of the single-phase high-entropy alloy CrMnFeCoNi after prolonged anneals at intermediate temperatures. Acta Mater 2016, 112: 40–52.
Pickering EJ, Muñoz-Moreno R, Stone HJ, et al. Precipitation in the equiatomic high-entropy alloy CrMnFeCoNi. Scripta Mater 2016, 113: 106–109.
Anandkumar M, Bhattacharya S, Deshpande AS. Low temperature synthesis and characterization of single phase multi-component fluorite oxide nanoparticle sols. RSC Adv 2019, 9: 26825–26830.
Anandkumar M, Bagul PM, Deshpande AS. Structural and luminescent properties of Eu3+ doped multi-principal component Ce0.2Gd0.2Hf0.2La0.2Zr0.2O2 nanoparticles. J Alloys Compd 2020, 838: 155595.
Hu YX, Anandkumar M, Joardar J, et al. Effective band gap engineering in multi-principal oxides (CeGdLa–Zr/Hf)O x by temperature-induced oxygen vacancies. Sci Rep 2023, 13: 2362.
Billo T, Fu FY, Raghunath P, et al. Ni-nanocluster modified black TiO2 with dual active sites for selective photocatalytic CO2 reduction. Small 2018, 14: 1702928.
Lun ZY, Ouyang B, Kwon DH, et al. Cation-disordered rocksalt-type high-entropy cathodes for Li-ion batteries. Nat Mater 2021, 20: 214–221.
Wright AJ, Wang QY, Hu CZ, et al. Single-phase duodenary high-entropy fluorite/pyrochlore oxides with an order-disorder transition. Acta Mater 2021, 211: 116858.
Hwang KJ, Shin M, Lee MH, et al. Investigation on the phase stability of yttria-stabilized zirconia electrolytes for high-temperature electrochemical application. Ceram Int 2019, 45: 9462–9467.
Guo M, Lu JQ, Wu YN, et al. UV and visible Raman studies of oxygen vacancies in rare-earth-doped ceria. Langmuir 2011, 27: 3872–3877.
Sobol AA, Voronko YK. Stress-induced cubic–tetragonal transformation in partially stabilized ZrO2: Raman spectroscopy study. J Phys Chem Solids 2004, 65: 1103–1112.
Ubaldini A, Carnasciali MM. Raman characterisation of powder of cubic RE2O3 (RE = Nd, Gd, Dy, Tm, and Lu), Sc2O3 and Y2O3. J Alloys Compd 2008, 454: 374–378.
Yu JQ, Cui L, He HQ, et al. Raman spectra of RE2O3 (RE = Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc and Y): Laser-excited luminescence and trace impurity analysis. J Rare Earths 2014, 32: 1–4.
López Granados M, Gurbani A, Mariscal R, et al. Deterioration of the oxygen storage and release properties of CeZrO4 by incorporation of calcium. J Catal 2008, 256: 172–182.
Ganduglia-Pirovano MV, Da Silva JLF, Sauer J. Density-functional calculations of the structure of near-surface oxygen vacancies and electron localization on CeO2(111). Phys Rev Lett 2009, 102: 026101.
Wu TT, Vegge T, Hansen HA. Improved electrocatalytic water splitting reaction on CeO2(111) by strain engineering: A DFT+ U study. ACS Catal 2019, 9: 4853–4861.
Huang YC, Wu SH, Hsiao CH, et al. Mild synthesis of size-tunable CeO2 octahedra for band gap variation. Chem Mater 2020, 32: 2631–2638.
Makuła P, Pacia M, Macyk W. How to correctly determine the band gap energy of modified semiconductor photocatalysts based on UV–vis spectra. J Phys Chem Lett 2018, 9: 6814–6817.
Thill AS, Lobato FO, Vaz MO, et al. Shifting the band gap from UV to visible region in cerium oxide nanoparticles. Appl Surf Sci 2020, 528: 146860.
1298
Views
344
Downloads
2
Crossref
2
Web of Science
2
Scopus
0
CSCD
Altmetrics
This is an open access article under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0, http://creativecommons.org/licenses/by/4.0/).