التفاصيل البيبلوغرافية
| العنوان: |
Operando Raman spectroscopy tracks oxidation state changes in an amorphous Co oxide material for electrocatalysis of the oxygen evolution reaction |
| المؤلفون: |
Pasquini, C., D Amario, L., Zaharieva, I., Dau, H. |
| سنة النشر: |
2020 |
| المجموعة: |
Helmholtz Zentrum Berlin (HZB): Publications |
| مصطلحات موضوعية: |
Large scale facilities for research with photons neutrons and ions |
| الوصف: |
Transition metal oxides are of high interest in both energy storage batteries and production of non fossil fuels by photo electrocatalysis. Their functionally crucial charge oxidation state changes and electrocatalytic properties are best investigated under electrochemical operation conditions. We established operando Raman spectroscopy for investigation of the atomic structure and oxidation state of a non crystalline, hydrated, and phosphate containing Co oxide material CoCat , which is an electrocatalyst for the oxygen evolution reaction OER at neutral pH and is structurally similar to LiCoO2 of batteries. Raman spectra were collected at various sub catalytic and catalytic electric potentials. 2H labeling suggests Co oxidation coupled to Co OH deprotonation at catalytic potentials. 18O labeling supports O O bond formation starting from terminally coordinated oxygen species. Two broad bands around 877 cm amp; 8722;1 and 1077 cm amp; 8722;1 are assigned to CoCat internal H2PO4 . Raman peaks corresponding to terminal oxide Co O or reactive oxygen species were not detectable; 1000 1200 cm amp; 8722;1 bands were instead assigned to two phonon Raman scattering. At an increasingly positive potential, the intensity of the Raman bands decreased, which is unexpected and explained by self absorption relating to CoCat electrochromism. A red shift of the Co O Raman bands with increasing potentials was described by four Gaussian bands of potential dependent amplitudes. By linear combination of Raman band amplitudes, we can follow individually the Co 2 3 and Co 3 4 redox transitions, whereas previously published x ray absorption spectroscopy analysis could determine only the averaged Co oxidation state. Our results show how electrochemical operando Raman spectroscopy can be employed as a potent analytical tool in mechanistic investigations on OER catalysis |
| نوع الوثيقة: |
article in journal/newspaper |
| اللغة: |
unknown |
| Relation: |
http://www.helmholtz-berlin.de/pubbin/oai_publication?VT=1&ID=109247 |
| الاتاحة: |
http://www.helmholtz-berlin.de/pubbin/oai_publication?VT=1&ID=109247 |
| Rights: |
info:eu-repo/semantics/closedAccess |
| رقم الانضمام: |
edsbas.5F907AE9 |
| قاعدة البيانات: |
BASE |