Tian, Chuanmu ; Maheu, Clément ; Huang, Xiaochun ; Oropeza, Freddy E. ; Major, Marton ; Brötz, Joachim ; Einert, Marcus ; Donner, Wolfgang ; Zhang, Kelvin Hongliang ; Hofmann, Jan P. (2024)
Evaluating the electronic structure and stability of epitaxially grown Sr-doped LaFeO₃ perovskite alkaline O₂ evolution model electrocatalysts.
In: RSC Applied Interfaces
doi: 10.1039/D4LF00260A
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
In this work, we have investigated the relationships between surface stability, electronic structure and O2 evolution reaction (OER) activity for epitaxial thin film La1−xSrxFeO3 (x = 0, 0.33, 0.8) model electrocatalysts before and after different electrochemical treatments. Cyclic voltammetry (CV) between +1.22 V and +1.92 V vs. RHE results in the continuous enhancement of OER performance of LaFeO3, while for La0.67Sr0.33FeO3 and La0.2Sr0.8FeO3 a gradual decrease of OER performance with increasing number of CV cycles was observed. A combination of atomic force microscopy, X-ray diffraction and X-ray reflectivity reveals that the surfaces of La1−xSrxFeO3 (x = 0, 0.33, 0.8) undergo surface morphology changes during OER treatment. Synchrotron ex situ X-ray photoemission spectroscopy data show a gradual down-shift of the Fermi level (EF) of LaFeO3 with increasing number of CV cycles, while near edge X-ray absorption fine structure spectroscopy (NEXAFS) at the Fe L-edge and O K-edge shows the presence of surface Fe4+ species as well as new hole states near the conduction band minimum upon electrochemical treatment, leading to a further enhancement of the electrochemical activity of LaFeO3. The newly formed hole state in LaFeO3 that appeared after 3 CV cycles remained constant upon progressing OER treatment. On the contrary, the decrease of OER performance of La0.67Sr0.33FeO3 and La0.2Sr0.8FeO3 with increasing CV cycles is attributed to an up-shift of EF along with a decrease of Fe4+ and hole state content after OER treatment. Furthermore, we found that the stability of the OER performance of La1−xSrxFeO3 is closely related to the leaching of Sr during OER, and the stability deteriorates with increasing Sr doping concentration in the pristine samples.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2024 |
| Autor(en): | Tian, Chuanmu ; Maheu, Clément ; Huang, Xiaochun ; Oropeza, Freddy E. ; Major, Marton ; Brötz, Joachim ; Einert, Marcus ; Donner, Wolfgang ; Zhang, Kelvin Hongliang ; Hofmann, Jan P. |
| Art des Eintrags: | Bibliographie |
| Titel: | Evaluating the electronic structure and stability of epitaxially grown Sr-doped LaFeO₃ perovskite alkaline O₂ evolution model electrocatalysts |
| Sprache: | Englisch |
| Publikationsjahr: | 4 Oktober 2024 |
| Ort: | Cambridge |
| Verlag: | RSC publishing |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | RSC Applied Interfaces |
| Kollation: | 8 Seiten |
| DOI: | 10.1039/D4LF00260A |
| URL / URN: | https://pubs.rsc.org/en/content/articlelanding/2024/lf/d4lf0... |
| Kurzbeschreibung (Abstract): | In this work, we have investigated the relationships between surface stability, electronic structure and O2 evolution reaction (OER) activity for epitaxial thin film La1−xSrxFeO3 (x = 0, 0.33, 0.8) model electrocatalysts before and after different electrochemical treatments. Cyclic voltammetry (CV) between +1.22 V and +1.92 V vs. RHE results in the continuous enhancement of OER performance of LaFeO3, while for La0.67Sr0.33FeO3 and La0.2Sr0.8FeO3 a gradual decrease of OER performance with increasing number of CV cycles was observed. A combination of atomic force microscopy, X-ray diffraction and X-ray reflectivity reveals that the surfaces of La1−xSrxFeO3 (x = 0, 0.33, 0.8) undergo surface morphology changes during OER treatment. Synchrotron ex situ X-ray photoemission spectroscopy data show a gradual down-shift of the Fermi level (EF) of LaFeO3 with increasing number of CV cycles, while near edge X-ray absorption fine structure spectroscopy (NEXAFS) at the Fe L-edge and O K-edge shows the presence of surface Fe4+ species as well as new hole states near the conduction band minimum upon electrochemical treatment, leading to a further enhancement of the electrochemical activity of LaFeO3. The newly formed hole state in LaFeO3 that appeared after 3 CV cycles remained constant upon progressing OER treatment. On the contrary, the decrease of OER performance of La0.67Sr0.33FeO3 and La0.2Sr0.8FeO3 with increasing CV cycles is attributed to an up-shift of EF along with a decrease of Fe4+ and hole state content after OER treatment. Furthermore, we found that the stability of the OER performance of La1−xSrxFeO3 is closely related to the leaching of Sr during OER, and the stability deteriorates with increasing Sr doping concentration in the pristine samples. |
| Zusätzliche Informationen: | This article is part of the themed collections: 25 years of The Netherlands’ Catalysis and Chemistry Conference (NCCC), Editor’s Choice – Ryan Richards and RSC Applied Interfaces HOT Article Collection |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Oberflächenforschung DFG-Sonderforschungsbereiche (inkl. Transregio) DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 1548: FLAIR – Fermi Level Engineering Applied to Oxide Electroceramics |
| Hinterlegungsdatum: | 15 Nov 2024 14:56 |
| Letzte Änderung: | 15 Nov 2024 14:56 |
| PPN: | 523600313 |
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