Oxygen storage properties of La1-xSrxFeO3-δ for chemicallooping reactions an in-situ neutron and synchrotron X-ray study

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1 Oxygen storage properties of La1-xSrxFeO3-δ for chemicallooping reactions an in-situ neutron and synchrotron X-ray study Daniel D. Taylor a, Nathaniel J. Schreiber a, Benjamin D. Levitas b, Wenqian Xu c, Pamela S. Whitfield d, and Efrain E. Rodriguez a,b a Department of Materials Science and Engineering, University of Maryland, College Park, Maryland, , USA b Department of Chemistry & Biochemistry, University of Maryland, College Park, Maryland, , USA. efrain@umd.edu c X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States d Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States Figure S1. Representation of the data reduction process for the in-situ neutron powder diffraction data. Shown is a pattern collected for La1/2Sr1/2FeO3-δ at 135 C under methane flow.

2 Figure S2. Representative refinement of an in-situ neutron powder diffraction pattern for La1/2Sr1/2FeO3-δ collected for 45 minutes at 135 C. Shown are the observed (black circles), refined (red line), difference (blue line) and cumulative χ 2 (green line) data. Tick marks indicate the positions of allowed reflections in the R-3c space group.

3 Figure S3. Representative refinement of an in-situ neutron powder diffraction pattern for La1/3Sr2/3FeO3-δ collected for 45 minutes at 135 C. Shown are the observed (black circles), refined (red line), difference (blue line) and cumulative χ 2 (green line) data. Tick marks indicate the positions of allowed reflections in the R-3c space group.

4 Figure S4. Representative refinement of an in-situ neutron powder diffraction pattern for SrFeO3-δ collected for 45 minutes at 135 C under flowing methane. Shown are the observed (black circles), refined (red line), difference (blue line) and cumulative χ 2 (green line) data. Tick marks indicate the positions of allowed reflections in the I4/mmm space group.

5 Figure S5. Representative refinement of an in-situ synchrotron X-ray powder diffraction pattern (λ = Å) for La2/3Sr1/3FeO3-δ collected for approximately 6.5 seconds at 700 C under air. Shown are the observed (black circles), refined (red line), difference (blue line) and cumulative χ 2 (green line) data. Tick marks indicate the positions of allowed reflections in the R-3c space group.

6 Figure S6. Representative refinement of an in-situ synchrotron X-ray powder diffraction pattern (λ = Å) for La1/2Sr1/2FeO3-δ collected for approximately 6.5 seconds at 700 C under air. Shown are the observed (black circles), refined (red line), difference (blue line) and cumulative χ 2 (green line) data. Tick marks indicate the positions of allowed reflections in the Pm-3m space group.

7 Figure S7. Representative refinement of an in-situ synchrotron X-ray powder diffraction pattern (λ = Å) for La1/3Sr2/3FeO3-δ collected for approximately 6.5 seconds at 700 C under air. Shown are the observed (black circles), refined (red line), difference (blue line) and cumulative χ 2 (green line) data. Tick marks indicate the positions of allowed reflections in the Pm-3m space group.

8 Figure S8. Representative refinement of an in-situ synchrotron X-ray powder diffraction pattern (λ = Å) for SrFeO3-δ collected for approximately 6.5 seconds at 700 C under air. Shown are the observed (black circles), refined (red line), difference (blue line) and cumulative χ 2 (green line) data. Tick marks indicate the positions of allowed reflections in the Pm-3m space group.

9 Figure S9. Overlay of in-situ NPD collected at 735 C and 835 C during the re-oxidation of SrFeO3-δ. Asterisks designate the location of impurity peaks.

10 Figure S10. Refined unit cell volume for LaFeO3-δ from in-situ neutron powder diffraction Figure S11. In-situ cycling SXRD data for LaFeO3 at 800 C. The sample showed no response to changes in atmosphere.

$synchrotron X-ray powder diffraction. Figure S13.$

11 Figure S12. Refined unit cell volume for SrFeO3-δ from in-situ synchrotron X-ray powder diffraction. Figure S13. Contour plot of La1/3Sr2/3FeO3-δ from in-situ synchrotron X-ray diffraction data for two complete cycles at 700 C (λ = Å).

12 Figure S14. Contour plot of La1/2Sr1/2FeO3-δ from synchrotron X-ray diffraction data for two complete cycles at 700 C (λ = Å). Figure S15. Contour plot of La2/3Sr1/3FeO3-δ from synchrotron X-ray diffraction data for two complete cycles at 700 C (λ = Å).

13 Figure S16. Refined unit cell volume for La1/3Sr2/3FeO3-δ from synchrotron X-ray diffraction data for two complete cycles at 500 C, 600 C, and 700 C.

14 Figure S17. Refined unit cell volume for La1/2Sr1/2FeO3-δ from synchrotron X-ray diffraction data for two complete cycles at 500 C, 600 C, and 700 C.

15 Figure S18. Overlay of oxygen content change (Δδ) with atmosphere cycling (15% CH4/N2 and 20% O2) as a function of temperature. Data from in-situ neutron powder diffraction experiments. Figure S19. Overlay of changes in unit cell volume, normalized per unit formula, between the patterns collected under each atmosphere, 15% CH4/N2 and 20% O2, as a function of temperature. Data from in-situ neutron powder diffraction experiments.

16 Figure S20. Overlay of LaB6 standard data collected with SXRD (17BM; blue circles) and NPD (POWGEN; red triangles). The x-axis covers the range shown in Figure 10. The similar peak resolution for both instruments suggests that the presence of peak splitting during reduction in SXRD, but not NPD experiments, is not due to an instrument resolution effect.

17 Table S1. NPD refinement parameters for La1/2Sr1/2FeO3-δ under air for 235 C-535 C La1/2Sr1/2FeO3-δ Air Temperature ( C) Space Group R-3cH R-3cH R-3cH R-3cH a (Å) (1) (6) (8) (1) c (Å) (5) (3) (4) (7) normalized volume (Å 3 ) (3) (2) (2) (4) Oxygen Content 2.97(3) 2.97(2) 3.01(2) 2.98(2) observed reflections La/Sr at (0 0 1/4) Biso 0.76(4) 0.92(2) 1.09(2) 1.29(2) Fe at (0 0 0) Biso 0.43(3) 0.45(2) 0.58(2) 0.68(2) O at (x 0 1/4) x (5) (3) (3) (4) occ 0.99(1) 0.990(6) 1.004(5) 0.994(5) U (1) (6) (7) 0.032(1) U (2) 0.014(1) 0.018(1) 0.022(2) U (1) (7) (8) 0.022(1) U (1) (5) (6) 0.011(1) U (7) (4) ( (7) U (1) (7) (9) (1) Rwp a χ a a the increased Rwp and χ 2 for this sample is due to the presence of an unidentified secondary phase in the pattern which is likely a small amount of reduced material remaining from the reduction step of the experiment. This secondary phase is not visible in the pattern collected at 335 C.

18 Table S2. NPD refinement parameters for La1/2Sr1/2FeO3-δ under air for 635 C-835 C La1/2Sr1/2FeO3-δ Air Temperature ( C) Space Group Pm-3m Pm-3m Pm-3m a (Å) (2) (2) (2) c (Å) normalized volume (Å 3 ) (1) (1) (1) oxygen content 2.99(2) 2.97(2) 2.95(2) observed reflections La/Sr at (1/2 1/2 1/2) Biso 1.49(2) 1.71(3) 1.94(4) Fe at (0 0 0) Biso 0.84(2) 0.96(2) 1.08(3) O at (0 0 1/2) occ 0.998(7) 0.992(7) 0.982(9) U11 & U (6) (6) (8) U (6) (6) (8) (U12, U13 & U23 = 0) Rwp χ

19 Table S3. NPD refinement parameters for La1/2Sr1/2FeO3-δ under methane for 135 C-435 C La1/2Sr1/2FeO3-δ Methane Temperature ( C) Space Group R-3cH R-3cH R-3cH R-3cH a (Å) (6) (3) (4) (5) c (Å) (2) (1) (2) (2) normalized volume (Å 3 ) 58.95(2) (9) (1) (1) oxygen content 2.98(1) 3.00(1) 2.98(2) 2.99(2) observed reflections La/Sr at (0 0 1/4) Biso 0.68(1) 0.83(1) 0.99(2) 1.17(2) Fe at (0 0 0) Biso 0.36(1) 0.45(1) 0.53(1) 0.4(1) O at (x 0 1/4) x (1) (2) (2) (3) occ 0.995(4) 0.999(5) 0.992(5) 0.996(6) U (3) (4) (5) (7) U (4) (6) (8) 0.019(1) U (4) (4) (5) (8) U (2) (3) (4) (6) U (2) (2) (3) (4) U (3) (4) (5) (8) Rwp χ

20 Table S4. NPD refinement parameters for La1/2Sr1/2FeO3-δ under methane for 535 C-835 C La1/2Sr1/2FeO3-δ Methane Temperature ( C) Space Group Pm-3m Pm-3m Pm-3m Pm-3m a (Å) (2) (2) (2) (2) c (Å) normalized volume (Å 3 ) (8) (1) (2) (1) oxygen content 2.90(2) 2.77(2) 2.68(2) 2.66(2) observed reflections La/Sr at (1/2 1/2 1/2) Biso 1.50(2) 2.12(3) 2.41(4) 2.67(4) Fe at (0 0 0) Biso 0.81(2) 1.26(3) 1.44(3) 1.63(3) O at (0 0 1/2) occ (7) 0.922(8) 0.894(8) 0.888(8) U11 & U (6) (8) (1) 0.078(1) U (6) (7) (8) (9) (U12, U13 & U23 = 0) Rwp χ

21 Table S5. NPD refinement parameters for La1/3Sr2/3FeO3-δ under air for 235 C-435 C La1/3Sr2/3FeO3-δ Air Temperature ( C) Space Group Pm-3m Pm-3m Pm-3m a (Å) (5) (5) (2) normalized volume (Å 3 ) (2) (2) (8) oxygen content 2.98(2) 2.97(2) 2.96(2) observed reflections La/Sr at (1/2 1/2 1/2) Biso 0.76(2) 0.93(2) 1.11(2) Fe at (0 0 0) Biso 0.39(1) 0.50(2) 0.60(2) O at (0 0 1/2) occ 0.993(6) 0.991(6) 0.988(6) U11 & U (3) (4) (4) U (4) (4) (4) (U12, U13 & U23 = 0) Rwp χ

22 Table S6. NPD refinement parameters for La1/3Sr2/3FeO3-δ under air for 535 C-835 C La1/3Sr2/3FeO3-δ Air Temperature ( C) Space Group Pm-3m Pm-3m Pm-3m Pm-3m a (Å) (2) (2) (2) (2) normalized volume (Å 3 ) (8) (8) (8) (2) oxygen content 2.93(2) 2.88(2) 2.83(2) 2.79(2) observed reflections La/Sr at (1/2 1/2 1/2) Biso 1.29(2) 1.52(2) 1.76(2) 2.06(3) Fe at (0 0 0) Biso 0.72(2) 0.84(2) 1.01(2) 1.21(2) O at (0 0 1/2) occ 0.977(5) 0.962(6) 0.942(6) 0.929(6) U11 & U (4) (4) (5) (6) U (5) (5) (6) (7) (U12, U13 & U23 = 0) Rwp χ

23 Table S7. NPD refinement parameters for La1/3Sr2/3FeO3-δ under methane for 135 C-435 C La1/3Sr2/3FeO3-δ Methane Temperature ( C) Space Group R-3cH Pm-3m Pm-3m Pm-3m a (Å) (2) (1) (1) (1) c (Å) (8) normalized volume (Å 3 ) (5) (5) (6) (6) oxygen content 2.99(1) 2.98(2) 2.97(2) 2.93(2) observed reflections La/Sr at (0 0 1/4) at (1/2 1/2 1/2) Biso 0.67(1) Biso 0.82(1) 0.97(2) 1.19(2) Fe at (0 0 0) at (0 0 0) Biso 0.36(1) Biso 0.43(1) 0.53(1) 0.66(1) O at (x 0 1/4) at (0 0 1/2) x (4) occ 0.994(5) 0.990(5) 0.976(5) occ 0.996(5) U11 & U (3) (3) (4) U (1) U (4) (4) (4) U (2) (U12, U13 & U23 = 0) U (1) U (9) U (6) U (1) Rwp χ

24 Table S8. NPD refinement parameters for La1/3Sr2/3FeO3-δ under methane for 535 C-835 C La1/3Sr2/3FeO3-δ Methane Temperature ( C) Space Group Pm-3m Pm-3m Pm-3m Pm-3m a (Å) (2) (3) (2) (2) c (Å) normalized volume (Å 3 ) (9) (1) (1) (1) oxygen content 2.81(2) 2.60(2) 2.53(2) 2.50(2) observed reflections La/Sr at (1/2 1/2 1/2) Biso 1.70(2) 2.49(4) 2.65(4) 2.92(4) Fe at (0 0 0) Biso 1.05(2) 1.68(3) 1.74(3) 1.97(3) O at (0 0 1/2) occ 0.935(6) 0.867(7) 0.843(7) 0.834(7) U11 & U (6) (8) (9) (9) U (6) (8) (8) (8) (U12, U13 & U23 = 0) Rwp χ

25 Table S9. NPD refinement parameters for SrFeO3-δ under air for 235 C-435 C SrFeO 3-δ Air Temperature ( C) Space Group I4/mmm Pm-3m Pm-3m a (Å) (1) (2) (2) c (Å) (1) normalized volume (Å 3 ) (1) (1) (1) oxygen content 2.82(6) 2.81(2) 2.78(2) observed reflections Sr(1) at (x 0 0) at (1/2 1/2 1/2) x (7) Biso 1.06(2) 1.25(2) Biso 0.78(2) Sr(2) at (x 0 1/2) x (7) Biso 0.78(2) Fe(1) at (0 0 1/4) at (0 0 0) Fe(2) at (1/4 1/4 1/4) Biso 0.42(2) Fe(3) at (1/2 0 1/4) Biso 0.42(2) Biso 0.66(2) 0.82(2) Biso 0.42(2) O(1) at (0 0 1/2) at (0 0 1/2) occ 1 occ 0.936(5) 0.927(6) Biso 1.2(5) U (4) (5) U (4) (5) O(2) at (x x z) U (5) (6) x (6) (U12, U13 & U23 = 0) z (6) occ 1 Biso 1.0(1) O(3) at (x x 1/2) x (5) occ 1 Biso 0.3(2) O(4) at (x x+1/2 1/4) x (7) occ 0.95(3) Biso 0.74(8) O(5) at (1/2 0 0) occ 1 Biso 1.6(4) R wp χ

26 Table S10. NPD refinement parameters for SrFeO3-δ under air for 535 C-835 C SrFeO3-δ Air Temperature ( C) Space Group Pm-3m Pm-3m Pm-3m Pm-3m a (Å) (3) (3) (3) (3) c (Å) normalized volume (Å 3 ) (2) (3) (1) (1) oxygen content 2.73(2) 2.66(2) 2.58(2) 2.52(2) observed reflections Sr(1) at (1/2 1/2 1/2) Biso 1.48(3) 1.74(3) 2.11(4) 2.56(4) Fe(1) at (0 0 0) Biso 1.02(2) 1.29(3) 1.67(3) 2.11(4) O(1) at (0 0 1/2) occ 0.910(6) 0.887(6) 0.862(6) 0.841(6) U (5) (6) (7) (8) U (5) (6) (7) (8) U (6) (7) (8) (9) (U12, U13 & U23 = 0) R wp χ

27 Table S11. NPD refinement parameters for SrFeO3-δ under methane for 135 C-535 C SrFeO3-δ Methane Temperature ( C) Space Group I4/mmm I4/mmm Pm-3m Pm-3m Pm-3m a (Å) (7) (7) (1) (1) (2) b (Å) c (Å) (1) (1) normalized volume (Å 3 ) (1) (1) (6) (7) (1) oxygen content 2.78(4) 2.76(5) 2.78(2) 2.73(2) 2.59(2) observed reflections Sr(1) at (x 0 0) at (1/2 1/2 1/2) x (5) (6) Biso 1.13(2) 1.42(2) 1.82(3) Biso 0.63(2) 0.82(2) Sr(2) at (x 0 1/2) x (6) (7) Biso 0.63(2) 0.82(2) Fe(1) at (0 0 1/4) at (0 0 0) Fe(2) at (1/4 1/4 1/4) Fe(3) at (1/2 0 1/4) Biso 0.31(1) 0.43(1) Biso 0.69(2) 0.94(2) 1.37(3) Biso 0.31(1) 0.43(1) Biso 0.31(1) 0.43(1) O(1) at (0 0 1/2) at (0 0 1/2) occ 1 1 occ 0.926(5) 0.910(5) 0.865(7) Biso 0.5(3) 1.0(4) U11,U (4) (4) (7) U (5) (5) (8) (U12, U13 & U23 = 0) O(2) at (x x z) x (2) (5) z (5) (5) occ 1 1 Biso 0.74(8) 0.97(9) O(3) at (x x 1/2) x (4) (4) occ 1 1 Biso 0.3(1) 0.4(1) O(4) at (x x+1/2 1/4) x (5) (6) occ 0.91(2) 0.89(2) Biso 0.68(7) 0.76(7) O(5) at (1/2 0 0) occ 1 1 Biso 0.8(2) 1.4(3) Rwp χ

28 Table 12. NPD refinement parameters for SrFeO3-δ under methane for 635 C-835 C SrFeO3-δ Methane Temperature ( C) Space Group Icmm Icmm Pm-3m a (Å) (1) (1) (3) b (Å) (3) (3) c (Å) (1) (1) normalized volume (Å 3 ) (2) (2) (2) oxygen content 2.39(3) 2.40(3) 2.28(3) observed reflections Sr(1) at (x y 1/2) at (1/2 1/2 1/2) Sr(2) x (5) (5) Biso 3.56(7) y (1) (1) Biso 1.69(6) 1.89(6) Fe(1) at (0 0 0) at (0 0 0) Biso 1.66(5) 1.81(6) Biso 3.28(6) Fe(2) at (x 1/4 x) x (5) (6) Fe(3) Biso 1.66(5) 1.81(6) O(1) at (1/4 y 1/4) at (0 0 1/2) y (2) (3) occ 0.759(1) occ 0.99(1) 1.00(1) U11,U (1) U (1) 0.009(1) U (1) U (2) 0.038(2) (U12, U13 & U23 = 0) U (1) 0.010(1) U (9) (9) (U12 & U23 = 0) O(2) at (x y 0) x (6) (7) y (2) (2) occ 0.95(1) 0.95(1) U (2) 0.30(3) U (2) 0.026(2) U (2) 0.055(3) U (1) 0.015(1) (U13 & U23 = 0) O(3) at (x 1/4 z) x 0.856(1) 0.856(1) z 0.634(1) 0.634(1) occ 0.45(2) 0.45(2) U (3) 0.015(4) U (3) 0.021(4) U (4) 0.022(4) U (2) (3) (U12 & U23 = 0) Rwp χ

Supplementary Information

Supplementary Information Structural manipulation and tailoring of dielectric properties in SrTi -x Fe x Ta x O 3 perovskites: Design of new lead free relaxors R. Shukla, S. J. Patwe, S. K. Deshpande 2,