Advantages of In Situ Mössbauer Spectroscopy in Catalyst Studies with Precaution in Interpretation of Measurements
Abstract
1. Introduction
2. Experimental Background and Selected Materials
2.1. Samples
2.2. In Situ Mössbauer Measurements
3. Mössbauer Studies on Zeolites (Example 1)
3.1. Demonstration of Extra-Framework Siting of Iron in Various Coordinations in 57Fe LTA Sample
3.2. Framework Iron Ions in Ferrierite Analog Ferrisilicate
4. Metals/Alloys (Example 2)
4.1. In Situ Dehydrochlorination of 1,2-Dichloroethane, ClCH2-CH2Cl
4.2. Oxidation of CO on Pt-Sn Catalyst at Room Temperature
5. Conclusions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Treatment | Atm. | Temp. of | Component | δ a | Δ b | FWHM c | Rel. Int. d |
---|---|---|---|---|---|---|---|
Meas. K | mm s−1 | mm s−1 | mm s−1 | % | |||
As rec. | air | 77 | Fe3+ | 0.45 | 1.04 | 0.59 | 65.9 |
Fe3+ | 0.46 | 0.63 | 0.35 | 34.1 | |||
630 K/ | vacuum | 300 | Fe3+ | 0.36 | 0.93 | 0.61 | 58.4 |
vac | Fe2+ | 0.83 | 0.45 | 0.28 | 25.5 | ||
Fe2+ | 0.87 | 2.44 | 0.89 | 16.1 | |||
570/H2 | H2 | 470 | Fe2+ | 0.72 | 0.52 | 0.29 | 71.2 |
Fe2+ | 0.87 | 1.71 | 0.70 | 28.8 | |||
None | H2 | 300 | Fe3+ | 0.25 | 0.75 | 0.37 | 8.7 |
(1st part) | Fe2+ | 0.84 | 0.50 | 0.24 | 16.2 | ||
Fe2+ | 1.08 | 1.12 | 0.68 | 52.1 | |||
Fe2+ | 1.12 | 2.19 | 0.51 | 23.0 | |||
None | H2 | 300 | Fe3+ | 0.28 | 0.80 | 0.35 | 8.2 |
(2nd part) | Fe2+ | 1.10 | 1.08 | 0.39 | 46.2 | ||
Fe2+ | 1.08 | 2.04 | 0.65 | 45.6 | |||
470/N20 | N2O | 470 | Fe3+ | 0.25 | 1.00 | 0.83 | 85.2 |
Fe2+ | 0.57 | 2.60 | 0.90 | 14.7 | |||
RT/H2 | H2 | 300 | Fe3+ | 0.34 | 1.06 | 0.74 | 73.0 |
Fe2+ | 0.88 | 2.46 | 1.62 | 27.0 | |||
450/H2 | H2 | 450 | Fe3+ | 0.21 | 0.99 | 0.67 | 94.1 |
Fe2+ | 1.37 | 1.25 | 0.52 | 6.9 | |||
540/H2 | H2 | 540 | Fe2+ | 0.57 | 0.60 | 0.95 | 39.2 |
Fe2+ | 0.69 | 0.53 | 0.23 | 50.5 | |||
Fe2+ | 0.78 | 1.89 | 0.48 | 10.2 | |||
300/air | air | 300 | Fe3+ | 0.32 | 0.85 | 0.61 | 56.7 |
Fe2+ | 1.15 | 2.09 | 0.63 | 43.2 |
Treatment | Temp. | Atm. | Comp. | δ a | Δ b | FWHM c | Rel. Int. d |
---|---|---|---|---|---|---|---|
Meas. (K) | mm s−1 | mm s−1 | mm s−1 | % | |||
Calcined | 300 | air | Fe3+ | 0.28 | 0.60 | 0.43 | 13.4 |
/air | Fe3+ | 0.35 | 1.03 | 0.74 | 86.6 | ||
620 K/vac | 300 | vacuum | Fe3+ | 0.24 | 1.98 | 0.61 | 70.9 |
Fe3+ | 0.37 | 1.17 | 1.08 | 29.1 | |||
620 K/H2 | 77 | hydrogen | Fe3+ | 0.33 | 1.83 | 0.38 | 13.6 |
Fe3+ | 0.54 | 1.16 | 0.82 | 37.6 | |||
Fe2+ | 1.17 | 1.98 | 0.77 | 36.4 | |||
Fe2+ | 1.15 | 3.03 | 0.56 | 12.3 | |||
None | 300 | hydrogen | Fe3+ | 0.30 | 1.62 | 0.59 | 35.6 |
Fe3+ | 0.31 | 0.97 | 0.61 | 56.1 | |||
Fe2+ | 0.78 | 2.46 | 0.44 | 3.3 | |||
Fe2+ | 1.26 | 2.49 | 0.49 | 5.0 | |||
None | 77 | hydrogen | Fe3+ | 0.40 | 1.48 | 0.69 | 52.5 |
(repeat) | Fe3+ | 0.40 | 0.88 | 0.54 | 35.9 | ||
Fe2+ | 1.25 | 2.26 | 0.25 | 1.9 | |||
Fe2+ | 1.40 | 2.96 | 0.61 | 9.7 | |||
620 K/vac | 300 | vacuum | Fe3+ | 0.22 | 1.98 | 0.56 | 60.8 |
Fe3+ | 0.46 | 1.52 | 1.25 | 39.2 | |||
620 K/H2 | 77 | hydrogen | Fe3+ | 0.37 | 1.66 | 0.45 | 13.5 |
Fe3+ | 0.42 | 1.13 | 0.79 | 28.6 | |||
Fe2+ | 1.09 | 2.21 | 0.76 | 36.9 | |||
Fe2+ | 1.42 | 2.53 | 0.59 | 21.0 | |||
140 K/vac | 140 K | vacuum | Fe3+ | 0.31 | 1.73 | 0.53 | 27.9 |
Fe3+ | 0.32 | 1.14 | 0.61 | 38.6 | |||
Fe2+ | 0.99 | 2.02 | 0.58 | 12.4 | |||
Fe2+ | 1.31 | 2.30 | 0.77 | 21.1 | |||
300 K/vac | 300 K | vacuum | Fe3+ | 0.25 | 1.63 | 0.52 | 47.5 |
Fe3+ | 0.32 | 0.98 | 0.59 | 26.9 | |||
Fe2+ | 1.04 | 2.14 | 0.96 | 25.6 | |||
620 K/vac | 300 | vacuum | Fe3+ | 0.24 | 1.96 | 0.50 | 58.6 |
Fe3+ | 0.40 | 1.27 | 0.95 | 27.6 | |||
Fe2+ | 1.22 | 1.50 | 0.91 | 13.7 |
Treatment | Comp. | δ a | Δ b | FWHM c | Rel. Int. d | Srel e |
---|---|---|---|---|---|---|
mm s−1 | mm s−1 | mm s−1 | % | |||
As prepared | Sn4+ | 0.07 | 0.50 | 0.89 | 100 | 1.00 |
H2/493 K | Sn4+ | 0.54 | - | 1.31 | 24 | 1.54 |
Pt-Sn(a) | 1.39 | - | 1.64 | 21 | ||
Pt-Sn(b) | 2.45 | - | 1.48 | 50 | ||
SnCl2 | 4.15 | - | 0.74 | 5 | ||
H2/623 K | Sn4+ | 0.38 | - | 0.68 | 6 | 1.74 |
Pt-Sn(a) | 1.11 | - | 1.29 | 19 | ||
Pt-Sn(b) | 2.16 | - | 1.69 | 64 | ||
SnCl2 | 3.95 | - | 1.14 | 12 | ||
React. mixt. f | Pt-Sn(a) | 1.22 | - | 1.59 | 43 | 1.42 |
473 K | Pt-Sn(b) ≈ β-Sn | 2.53 | - | 1.76 | 52 | |
SnCl2 | 3.96 | - | 1.58 | 5 |
Treatment | Comp. | 77 K | 300 K | |||||||
---|---|---|---|---|---|---|---|---|---|---|
δ a | Δ b | FWHM c | Rel. Int. d | δ a | Δ b | FWHM c | Rel. Int. d | f(rel) e | ||
mm s−1 | mm s−1 | mm s−1 | % | mm s−1 | mm s−1 | mm s−1 | % | |||
As received | Sn4+ | 0.00 | 0.72 | 1.17 | 74 | 0.01 | 0.64 | 1.07 | 77 | 4.14 |
PtSn(a) | 1.49 | - | 1.43 | 26 | 1.42 | - | 1.16 | 23 | 4.87 | |
H2/573 K | Sn4+(surf) | 0.49 | 0.42 | 0.59 | 6 | 0.53 | 0.43 | 0.39 | 4 | 7.43 |
Sn2+ | 2.88 | 2.11 | 1.06 | 9 | ||||||
PtSn(a) | 1.31 | - | 1.27 | 37 | 1.41 | - | 1.25 | 55 | 3.78 | |
PtSn(b) | 2.32 | - | 2.00 | 48 | 2.38 | - | 1.60 | 40 | 6.50 | |
CO + O2 | Sn4+ | 0.00 | 0.68 | 1.25 | 72 | 0.01 | 0.72 | 1.06 | 83 | 2.88 |
300 K | Sn4+(surf) | 0.86 | - | 1.10 | 16 | 0.93 | - | 0.88 | 8 | 6.28 |
PtSn | 1.77 | - | 1.41 | 12 | 1.60 | - | 1.32 | 9 | 4.06 | |
H2/300 K | Sn4+ | 0.04 | 0.70 | 1.09 | 42 | 0.05 | 0.71 | 1.03 | 45 | 5.49 |
PtSn(a) | 1.22 | - | 1.58 | 24 | 1.36 | - | 1.54 | 32 | 4.53 | |
PtSn(b) | 2.31 | - | 1.79 | 33 | 2.39 | - | 1.48 | 23 | 7.35 | |
CO + O2 | Sn4+ | −0.19 | 0.57 | 1.10 | 53 | |||||
300 K | Sn4+(surf) | 0.66 | - | 1.24 | 29 | |||||
Sn2+ | 3.23 | 2.30 | 1.30 | 7 | ||||||
PtSn(a) | 1.40 | - | 1.41 | 12 | ||||||
CO/300 K | Sn4+ | −0.02 | 0.71 | 1.13 | 62 | 0.00 | 0.73 | 0.99 | 64 | 3.54 |
Sn4+(surf) | 0.88 | - | 1.17 | 14 | 0.80 | - | 1.10 | 8 | 5.79 | |
PtSn | 1.86 | - | 1.69 | 24 | 1.72 | - | 1.74 | 27 | 3.14 |
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Lázár, K. Advantages of In Situ Mössbauer Spectroscopy in Catalyst Studies with Precaution in Interpretation of Measurements. Spectrosc. J. 2025, 3, 10. https://doi.org/10.3390/spectroscj3010010
Lázár K. Advantages of In Situ Mössbauer Spectroscopy in Catalyst Studies with Precaution in Interpretation of Measurements. Spectroscopy Journal. 2025; 3(1):10. https://doi.org/10.3390/spectroscj3010010
Chicago/Turabian StyleLázár, Károly. 2025. "Advantages of In Situ Mössbauer Spectroscopy in Catalyst Studies with Precaution in Interpretation of Measurements" Spectroscopy Journal 3, no. 1: 10. https://doi.org/10.3390/spectroscj3010010
APA StyleLázár, K. (2025). Advantages of In Situ Mössbauer Spectroscopy in Catalyst Studies with Precaution in Interpretation of Measurements. Spectroscopy Journal, 3(1), 10. https://doi.org/10.3390/spectroscj3010010