| 330 | 0 | 305 |
| 下载次数 | 被引频次 | 阅读次数 |
PrBaFe_2O5+δ(PBF)是中温固体氧化物燃料电池的阴极材料之一，然而PBF材料的结构还存在四方结构和立方结构的争议，并且氧还原反应机理还不清晰，需要进一步深入研究。目前的相关报道主要是对PBF材料的电化学性能进行优化，对结构和氧还原反应机理的报道较少。本工作通过密度泛函理论计算、X射线衍射、透射电子显微镜、电化学阻抗谱和弛豫时间分布法等方法研究PBF材料的晶体结构和氧还原反应机理，对PBF材料的合成过程、晶体结构和氧还原反应限制性步骤进行了详细分析。结果表明，由PrFeO3和BaFeO3在800℃固溶合成的PBF呈现四方结构(空间群：P4/mmm)。在空气和体积分数为20%的H2(H_2+N2)气氛中晶体结构稳定，在纯氢气中部分分解为Fe、BaFeO3和Pr_2O3。氧还原反应限制性步骤在400～550℃为氧原子电离和氧离子传输，600～700℃为氧气的化学吸附和氧分子的解离，700～800℃为氧气的物理吸附。
Abstract：Introduction Compared to Co-based cathode materials,Fe-based perovskite materials exhibit superior thermal stability and electrochemical stability,but they have lower conductivity and redox activity.The Fe-based perovskite materials are regarded as one of the cathode materials with a great development potential for SOFCs due to their lower thermal expansion coefficient and cost.In the LnBaFe_2O5+δ(Ln=lanthanide elements,Y) double perovskite materials,PrBaFe_2O5+δ(PBF) has the lowest activation energy for the redox reaction,making it a promising alternative material for SOFC cathodes.For the PBF materials,there are a few reports on their crystal structure and redox reaction mechanisms.There is still a debate regarding the tetragonal and cubic structures of PBF materials.Also,the mechanism of the redox reaction remains unclear and requires a further in-depth investigation.This study was to prepare the PBF cathode materials by a sol-gel method.In addition,the synthesis process,crystal structure,and redox reaction mechanisms of PBF materials were also investigated.Methods The average binding energy of the possible structures of PBF was calculated by the Cambridge Sequential Total Energy Package(CASTEP) module in Material Studio software.The reflex module in Materials Studio was used to simulate the X-ray diffraction(XRD) patterns after optimizing the structures.The PBF powder was prepared by a sol-gel method,and the precursors were analyzed by thermgravity-differential thermal analysis(TG-DTA),X-ray diffraction(XRD) and transmission electron microscopy(TEM).The calcined samples were treated in air,20%(in volume) H2(H_2+N2) atmosphere,and pure H2 at 800 ℃ for 20h.In addition,the electrochemical impedance spectra of the PBF|SDC|PBF symmetrical cell were measured,and analyzed via distribution of relaxation time s(DRT).Results and discussion The simulated XRD patterns show distinct differences in the XRD peaks of the four PBF structures with the main difference between the tetragonal and simple cubic structures after 80°. The characteristic double peak of the double perovskite is attributed to an increased lattice distortion caused by an increase in oxygen vacancy defects,while its structural symmetry remains unchanged.The tetragonal structure has the lowest average binding energy,while the simple cubic structure has the highest.This indicates that the likelihood of PBF adopting a simple cubic structure is minimal,whereas the likelihood of it adopting a tetragonal structure is maximal.The results of TG-DTA and XRD indicate that the precursors form BaFeO3 and PrFeO3 heat-treated at 800 ℃ and a subsequent two-phase solid solution process after 800 ℃.Pure PBF is obtained after roasting in air at 1200 ℃ for 5 h.In a 20%H2(H_2+N2)atmosphere,pure PBF can be achieved at 800 ℃,indicating that the 20%H2(H_2+N2) treatment accelerates the solid solution of BaFeO3 and PrFeO3.The PBF is structurally stable in both air and a 20%H2(H_2+N2) atmosphere,but decomposes into Fe,BaFeO3,and Pr_2O3 in pure H2,indicating that PBF material decomposes under pure hydrogen and is not suitable for use on the anode side.Also,the occupancy of O in the [Pr-O] layer decreases,indicating that more oxygen vacancies are generated after reduction.The analysis of the crystal structure shows that the unit cell is elongated in a 20%H2(H_2+N2) atmosphere due to the formation of more oxygen vacancies in the [Pr-O] layer.Based on the different relaxation times of various cathodic reactions,the DRT analysis indicates that the limiting step of the ORR at 400-550 ℃ involves the ionization of oxygen atoms and the transport of oxygen ions,while that at 600-700 ℃ involves the chemisorption of oxygen and the dissociation of oxygen molecules.At 700-800 ℃,the limiting step is related to the physisorption of oxygen.Clearly,the conclusions drawn from time-domain analysis differ from those obtained through conventional impedance spectroscopy.At 750-800 ℃,time-domain analysis indicates that the limiting step affecting the ORR is the physisorption of oxygen,whereas conventional impedance spectroscopy indicates that it is the ionization of oxygen atoms and the transport of oxygen ions.This study posits that both sets of results can serve as a basis for optimizing the oxygen catalytic performance of PBF materials.Conclusions This study investigated the formation process,structure,stability,and oxygen catalytic performance of PBF materials by DFT calculations,XRD,TEM,EIS,and DRT analysis.The PBF synthesized through the solid solution formation of PrFeO3 and BaFeO3 at 800 ℃ exhibited a tetragonal structure(i.e.,space group:P4/mmm).The crystal structure remained stable in air and20%H2(H_2+N2) atmosphere,but partially decomposed into Fe,BaFeO3,and Pr_2O3 in pure hydrogen.The limiting steps of the oxygen reduction reaction(ORR) were identified as the ionization of oxygen atoms and the transport of oxygen ions at 400-550℃,chemisorption of oxygen and dissociation of oxygen molecules at 600-700 ℃,and physisorption of oxygen at 700-800 ℃.
[1] ZHANG W, HU Y H. Recent progress in design and fabrication of SOFC cathodes for efficient catalytic oxygen reduction[J]. Catal Today,2023, 409:71–86.
[2] AHMAD M Z, AHMAD S H, CHEN R S, et al. Review on recent advancement in cathode material for lower and intermediate temperature solid oxide fuel cells application[J]. Int J Hydrogen Energ,2022, 47(2):1103–1120.
[3] TAHIR N N M, BAHARUDDIN N A, SAMAT A A, et al. A review on cathode materials for conventional and proton-conducting solid oxide fuel cells[J]. J Alloy Compd, 2022, 894:162458.
[4] HARRISON C M, SLATER P R, STEINBERGER-WILCKENS R. A review of solid oxide fuel cell cathode materials with respect to their resistance to the effects of chromium poisoning[J]. Solid State Ionics,2020, 354:115410.
[5] CHEN S G, ZHANG H X, YAO C G, et al. Review of SOFC cathode performance enhancement by surface modifications:Recent advances and future directions[J]. Energy Fuels, 2023, 37(5):3470–3487.
[6] ANWAR M, SHAIKH ABDUL M A, KHAN U M, et al. A review of X-ray photoelectron spectroscopy technique to analyze the stability and degradation mechanism of solid oxide fuel cell cathode materials[J].Materials, 2022, 15(7):2540.
[7] WU K, FU L, ZHOU J, et al. Enhanced oxygen reduction reaction of LaSrCoO4–Ce0.9Mn0.1O2 composite cathode for solid oxide fuel cells[J].Ceram Int, 2023, 49(6):9848–9856.
[8] WANG Y X, ZHAO X Y, LüS Q, et al. Synthesis and characterization of SmSrCo2-xMnxO5+δ(x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0)cathode materials for intermediate-temperature solid-oxide fuel cells[J]. Ceram Int, 2014,40(7):11343–11350.
[9] LOUREIRO F J A, MACEDO D A, NASCIMENTO R M, et al.Cathodic polarisation of composite LSCF-SDC IT-SOFC electrode synthesised by one-step microwave self-assisted combustion[J]. J Eur Ceram Soc, 2019, 39(5):1846–1853.
[10] CAI C K, XIE M Y, XUE K, et al. Enhanced electrochemical performance of La0.6Sr0.4Co0.2Fe0.8O3–δ cathode via Ba-doping for intermediate-temperature solid oxide fuel cells[J]. Nano Res, 2022,15(4):3264–3272.
[11] XIE M Y, CAI C K, LIU X J, et al. Improved durability of high-performance intermediate-temperature solid oxide fuel cells with a Ba-doped La0.6Sr0.4Co0.2Fe0.8O3-δ cathode[J]. ACS Appl Mater Interfaces, 2022, 14(29):33052–33063.
[12] WANG S L, ZAN J N, QIU W W, et al. Evaluation of perovskite oxides LnBaCo2O5+δ(Ln=La, Pr, Nd and Sm)as cathode materials for IT-SOFC[J]. J Electroanal Chem, 2021, 886:115144.
[13] ZHOU D C, YUAN C, CHEN X Y, et al. A-site doublelanthanide-doped La1-xPrxBa Co2O5+δ cathode materials for intermediatetemperature solid oxide fuel cells[J]. J Mater Sci, 2022, 57(30):14398–14412.
[14] LIU B, YANG J J, YAN D, et al. Novel PrBa0.9Ca0.1Co2-xZnxO5+δdouble-perovskite as an active cathode material for high-performance proton-conducting solid oxide fuel cells[J]. Int J Hydrogen Energ, 2020,45(55):31009–31016.
[15] SONG X Q, LE S R, ZHU X D, et al. High performance BaFe1-xBixO3-δ as cobalt-free cathodes for intermediate temperature solid oxide fuel cells[J]. Int J Hydrogen Energ, 2017, 42(24):15808–15817.
[16] WU M, CAI H D, JIN F J, et al. Assessment of cobalt–free ferrite–based perovskite Ln0.5Sr0.5Fe0.9Mo0.1O3–δ(Ln?=?lanthanide)as cathodes for IT-SOFCs[J]. J Eur Ceram Soc, 2021, 41(4):2682–2690.
[17] WANG Z, LV P F, YANG L, et al. Ba0.95La0.05Fe0.8Zn0.2O3-δ cobalt-free perovskite as a triple-conducting cathode for proton-conducting solid oxide fuel cells[J]. Ceram Int, 2020, 46(11):18216–18223.
[18] JU Y W, LEE S, KANG B S, et al. Phase transition of doped LaFeO3anode in reducing atmosphere and their power generation property in intermediate temperature solid oxide fuel cell[J]. Int J Hydrogen Energ,2019, 44(56):29641–29647.
[19] LI H, WEI B, SU C X, et al. Novel cobalt-free layered perovskite LaBaFe2-xNbxO6-δ(x=0–0.1)as cathode for solid oxide fuel cells[J]. J Power Sources, 2020, 453:227875.
[20] GUO D, LI A Y, LU C L, et al. High activity and stability of cobalt-free SmBa0.5Sr0.5Fe2O5+δ perovskite oxide as cathode material for solid oxide fuel cells[J]. Ceram Int, 2023, 49(21):34277–34290.
[21] ZHANG Y, NIU B B, HAO X H, et al. Layered oxygen-deficient double perovskite GdBaFe2O5+δ as electrode material for symmetrical solid-oxide fuel cells[J]. Electrochim Acta, 2021, 370:137807.
[22] WANG F, QI J Y, SHAN P K, et al. Co-free and Sr-free double-perovskite oxide PrBaFe1.9Nb0.1O5+δ as a potential electrode material for symmetrical solid oxide fuel cells[J]. Ionics, 2024, 30(10):6305–6319.
[23] CHEN D J, WANG F C, SHI H G, et al. Systematic evaluation of co-free LnBaFe2O5+δ(Ln=Lanthanides or Y)oxides towards the application as cathodes for intermediate-temperature solid oxide fuel cells[J]. Electrochim Acta, 2012, 78:466–474.
[24] LIU C H, WANG F, NI Y, et al. Ta-doped PrBaFe2O5+δ double perovskite as a high-performance electrode material for symmetrical solid oxide fuel cells[J]. Int J Hydrogen Energ, 2023, 48(26):9812–9822.
[25] LU C L, NIU B B, YI W D, et al. Efficient symmetrical electrodes of PrBaFe2–xCoxO5+δ(x=0, 0.2, 0.4)for solid oxide fuel cells and solid oxide electrolysis cells[J]. Electrochim Acta, 2020, 358:136916.
[26] CHEN T, PANG S L, SHEN X Q, et al. Evaluation of Ba-deficient PrBa1–xFe2O5+δ oxides as cathode materials for intermediatetemperature solid oxide fuel cells[J]. RSC Adv, 2016, 6(17):13829–13836.
[27] WEN C Y, CHEN K, GUO D, et al. High performance and stability of PrBa0.5Sr0.5Fe2O5+δ symmetrical electrode for intermediate temperature solid oxide fuel cells[J]. Solid State Ionics, 2022, 386:116048.
[28] REN R Z, WANG Z H, MENG X G, et al. Boosting the electrochemical performance of Fe-based layered double perovskite cathodes by Zn2+doping for solid oxide fuel cells[J]. ACS Appl Mater Interfaces, 2020,12(21):23959–23967.
[29] TAO Y K, ZHOU Y, LI W Y, et al. Intermediate-temperature solid oxide fuel cells with high performance cobalt-doped Pr0.5Ba0.5FeO3-δanodes[J]. J Alloy Compd, 2018, 741:1091–1097.
[30] LEE D, KIM D, SON S J, et al. Simultaneous A-and B-site substituted double perovskite(AA’B2O5+δ)as a new high-performance and redox-stable anode material for solid oxide fuel cells[J]. J Power Sources, 2019, 434:226743.
[31] DING H P, TAO Z T, LIU S, et al. A high-performing sulfur-tolerant and redox-stable layered perovskite anode for direct hydrocarbon solid oxide fuel cells[J]. Sci Rep, 2015, 5:18129.
[32] JIANG L, LI F S, WEI T, et al. Evaluation of Pr1+xBa1–xCo2O5+δ(x=0–0.30)as cathode materials for solid-oxide fuel cells[J]. Electrochim Acta, 2014, 133:364–372.
[33] LI W X, LI X X, WANG C, et al. Enhancing the electrocatalytic activity of perovskite electrodes by atomic layer-deposited doped CeO2for symmetrical solid oxide fuel cells[J]. Sep Purif Technol, 2022, 302:122135.
[34] LI G D, GOU Y J, CHENG X J, et al. Enhanced electrochemical performance of the Fe-based layered perovskite oxygen electrode for reversible solid oxide cells[J]. ACS Appl Mater Interfaces, 2021, 13(29):34282–34291.
[35] ZHANG B Z, ZHANG S W, HAN H R, et al. Cobalt-free double perovskite oxide as a promising cathode for solid oxide fuel cells[J].ACS Appl Mater Interfaces, 2023, 15(6):8253–8262.
[36] ZHANG H X, YANG J X, WANG P F, et al. Novel cobalt-free perovskite PrBaFe1.9Mo0.1O5+δ as a cathode material for solid oxide fuel cells[J]. Solid State Ionics, 2023, 391:116144.
[37] PELOSATO R, CORDARO G, STUCCHI D, et al. Cobalt based layered perovskites as cathode material for intermediate temperature solid oxide fuel cells:A brief review[J]. J Power Sources, 2015, 298:46–67.
[38] KANG H S, GREWAL S, LI H Y, et al. Effect of surface-specific treatment by infiltration into LaNi6Fe4O3–δ cathodic backbone for solid oxide fuel cells[J]. J Electrochem Soc, 2019, 166(4):F255–F263.
[39] PERDEW J P, BURKE K, ERNZERHOF M. Generalized gradient approximation made simple[J]. Phys Rev Lett, 1996, 77(18):3865–3868.
[40] VANDERBILT D. Soft self-consistent pseudopotentials in a generalized eigenvalue formalism[J]. Phys Rev B, 1990, 41(11):7892–7895.
[41] TOBY B H. EXPGUI. A graphical user interface for GSAS[J]. J Appl Crystallogr, 2001, 34(2):210-213.
[42] LARSON A C, VON DREELE R B. General structure analysis system(GSAS)[R]. Los Alamos National Laboratory Report LAUR, 2004:86-748.
[43]梁敬魁.粉末衍射法测定晶体结构[M].北京:科学出版社, 2003:798.
[44] WAN T H, SACCOCCIO M, CHEN C, et al. Influence of the discretization methods on the distribution of relaxation times deconvolution:Implementing radial basis functions with DRTtools[J].Electrochim Acta, 2015, 184:483–499.
[45] LIU J P, CIUCCI F. The Gaussian process distribution of relaxation times:A machine learning tool for the analysis and prediction of electrochemical impedance spectroscopy data[J]. Electrochim Acta,2020, 331:135316.
[46] GU H X, YANG G M, HU Y, et al. Enhancing the oxygen reduction activity of PrBaCo2O5+δ double perovskite cathode by tailoring the calcination temperatures[J]. Int J Hydrogen Energ, 2020, 45(48):25996–26004.
[47] LU F F, XIA T, LI Q, et al. Heterostructured simple perovskite nanorod-decorated double perovskite cathode for solid oxide fuel cells:Highly catalytic activity, stability and CO2-durability for oxygen reduction reaction[J]. Appl Catal B Environ, 2019, 249:19–31.
[48] PANG S L, XU J, SU Y J, et al. The role of A-site cation size mismatch in tune the catalytic activity and durability of double perovskite oxides[J]. Appl Catal B Environ, 2020, 270:118868.
[49] YOON J S, YI E J, CHOI B H, et al. Methane oxidation behavior over La0.08Sr0.92Fe0.20Ti0.8O3-δ perovskite oxide for SOFC anode[J]. Ceram Int, 2014, 40(1):1525-1529.
基本信息:
DOI：10.14062/j.issn.0454-5648.20240682
中图分类号:O646;TM911.4
引用信息:
[1]薛柯,蔡长焜,谢满意,等.固体氧化物燃料电池PrBaFe_2O_(5+δ)阴极材料的结构和氧还原反应机理[J].硅酸盐学报,2025,53(10):3022-3030.DOI:10.14062/j.issn.0454-5648.20240682.
基金信息:
国家自然科学基金(51974167)