Influence of alkaline-earth metal substitution on structure, electrical conductivity and oxygen transport properties of perovskite-type oxides La0.6A0.4FeO3−δ(A = Ca, Sr and Ba)

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Supplementary information

Influence of alkaline-earth metal substitution on structure, electrical

conductivity and oxygen transport properties of perovskite-type oxides

La

0.6

A

0.4

FeO

3-δ

(A = Ca, Sr and Ba)

Jia Song,a_{De Ning}b_{and Henny. J.M. Bouwmeester}a

a_{Electrochemistry Research Group, Membrane Science and Technology, MESA+ Institute for}

Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands

b_{Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin,}

Germany

Electronic Supplementary Material (ESI) for Physical Chemistry Chemical Physics.

This journal is © the Owner Societies 2020

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Table S1. Structural data of LCF64, LSF64 and LBF64 from Rietveld refinements of room-temperature XRD data. The numbers in parentheses denote standard deviations in units of the least significant digits.

Atom Site x y z B occ

La0.6Ca0.4FeO3-δ Pnma, a = 5.5138(1) Å, b = 7.7574(1) Å, c = 5.4896(1) Å La 4c 0.0215(1) 0.25 0.9991(12) 0.86(1) 0.6 Ca 4c 0.0215(1) 0.25 0.9991(12) 0.86(1) 0.4 Fe 4b 0.5 0 0 1.16(2) 1 O1 4c 0.2806(15) 0.0142(11) 0.7267(18) 0.09(9) 2 O2 8d 0.4939(17) 0.25 0.1391(18) 7.0(3) 1 La0.6Sr0.4FeO3-δ 𝑅 ̅3𝑐, a = b = 5.52260(6) Å, c = 13.4462(2) Å La 4c 0 0 0.25 1.7002(3) 0.6 Sr 4c 0 0 0.25 1.7002(3) 0.4 Fe 4b 0.3333 0.6667 0.1667 1.5771(7) 1 O 4c 0.5468(11) 0 0.25 1.2295(18) 3 La0.6Ba0.4FeO3-δ 𝑃𝑚 ̅3𝑚, a = b = c = 3.92652(2) Å La 4c 0 0 0 2.41(2) 0.6 Ba 4c 0 0 0 2.41(2) 0.4 Fe 4b 0.5 0.5 0.5 2.28(4) 1 O 4c 0.5 0.5 0 3.57(9) 3

Table S2. Activation energies of Dchem and kchem of LCF64, LSF64 and LBF64 extracted from data of

ECR experiments, following pO2 step changes 0.21  0.1 atm (Red) and 0.1  0.21 atm (Ox).

Dchem kchem

Red Ox Red Ox

Materials

Ea (kJ mol-1) Ea (kJ mol-1) Ea (kJ mol-1) Ea (kJ mol-1)

LCF64 98 ± 2 97 ± 1 146 ± 2 144 ± 1

LSF64 93.6 ± 0.4 93.9 ± 0.4 86 ± 1 82 ± 1

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Table S3. Activation energies of Ds of LCF64, LSF64 and LBF64 extracted from data of ECR

experiments, following pO2 step changes 0.21  0.1 atm (Red) and 0.1  0.21 atm (Ox).

Ds Red Ox Materials Ea (kJ mol-1) Ea (kJ mol-1) LCF64 139 ± 2 138 ± 2 LSF64 143 ± 1 145 ± 1 LBF64 103 ± 1 106 ± 1

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Fig. S1 In situ high temperature XRD patterns for (a) LCF64, (b) LSF64, and (c) recorded between 20° and 56° in air.

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0.85 0.90 0.95 1.00 1.05 1.10 1.96 1.97 1.98 1.99 2.00 (b) (a) LCF64 LSF64 LBF64 Fe -O b on d le ng th [Å ] 1000/T [K-1_] 900 850 800 750 700 650 T [C] 0.85 0.90 0.95 1.00 1.05 1.10 160 165 170 175 180 LCF64 LSF64 LBF64 Fe -O -F e an gl e [ ] 1000/T [K-1_] 900 850 800 750 700 650 T [C]

Fig. S2 (a) Fe-O-Fe angle and (b) Fe-O bond distance for LCF64, LSF64 and LBF64 obtained from Rietveld refinements of HT-XRD patterns recorded in ambient air.

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7 99.5 99.6 99.7 99.8 99.9 100.0 100% W ei gh t [ % ] Reference point ( = 0) 0 200 400 600 800 T [ C] 200 400 600 800 1000 1200 0 20 40 60 80 90 46 21 10 pO2 [% ] Time [min] 4.5

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-1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 -2.5 -2.0 -1.5 -1.0 LCF64 lo g(    ) log(pO₂ [atm]) (a) 800 °C 775 °C 750 °C 725 °C 900 °C 875 °C 850 °C 825 °C 700 °C 675 °C 650 °C -1/2 -1/4 -1/8 0.1 1 pO2 [atm] -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 -2.5 -2.0 -1.5 -1.0 LSF64 lo g(    ) log(pO₂ [atm]) (b) 800 °C 775 °C 750 °C 725 °C 900 °C 875 °C 850 °C 825 °C 700 °C 675 °C 650 °C -1/2 -1/4 -1/8 0.1 1 pO2 [atm] -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 -1.6 -1.4 -1.2 -1.0 -0.8 _LBF64 lo g(    ) log(pO₂ [atm]) (c) 800 °C 775 °C 750 °C 725 °C 900 °C 875 °C 850 °C 825 °C 700 °C 675 °C 650 °C -1/8 -1/4-1/2 0.1 1 pO2 [atm]

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9 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 2.93 2.94 2.95 2.96 2.97 2.98 LSF64 900 C Kuhn et al.37 This work 3-   log(pO₂ [atm]) 800 C 0.1 1 pO₂ [atm]

Fig. S5 Comparison of the data of oxygen stoichiometry (3-δ) at 800 °C and 900 °C for LSF64 from this study with corresponding data obtained by Kuhn et al.37_{Lines are drawn to guide the eye.}

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-2.0 -1.5 -1.0 -0.5 0.0 40 60 80 100 120 140 160 180 200 LCF64 LSF64 LBF64  [S c m -1 ] log(pO₂) [atm] (a) 0.01 0.1 1 pO₂ [atm] -1.5 -1.0 -0.5 0.0 0.1 0.2 0.3 0.4 0.5 0.6 log(pO₂) [atm] [F e  Fe] 1/4 LCF64 LSF64 LBF64 1/8 (b) 0.1 1 pO₂ [atm] -1.5 -1.0 -0.5 0.0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 log(pO₂) [atm]



h [c m 2 V -1 s -1 ] LCF64 LSF64 LBF64 (c) 0.1 1 pO₂ [atm]

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11 0.85 0.90 0.95 1.00 1.05 1.10 100 200 300 400 500 600 LCF64 LSF64 LBF64    1000/T [K-1_] 900 850 800 750 700 650 T [C]

Fig. S7 Inverse temperature dependence of the thermodynamic factor for LCF64, LSF64 and LBF64 calculated from data of thermogravimetry obtained at pO2 = 0.1416 atm. The specified pO2

corresponds to the logarithmic average of the initial and final values of the pO2 step change