English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
Add to Basket
  Local TagsRelease HistoryDetailsSummary

Released
Journal Article

In Situ/Operando Soft X-ray Spectroscopic Identification of a Co4+ Intermediate in the Oxygen Evolution Reaction of Defective Co3O4 Nanosheets

MPS-Authors
/persons/resource/persons126666

Hu,  Zhiwei
Zhiwei Hu, Physics of Correlated Matter, Max Planck Institute for Chemical Physics of Solids, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Huang, Y.-C., Chen, W., Xiao, Z., Hu, Z., Lu, Y.-R., Chen, J.-L., et al. (2022). In Situ/Operando Soft X-ray Spectroscopic Identification of a Co4+ Intermediate in the Oxygen Evolution Reaction of Defective Co3O4 Nanosheets. The Journal of Physical Chemistry Letters, 13(35), 8386-8396. doi:10.1021/acs.jpclett.2c01557.


Cite as: https://hdl.handle.net/21.11116/0000-000B-4476-4
Abstract
Defect engineering is an important means of improving the electrochemical performance of the Co3O4 electrocatalyst in the oxygen evolution reaction (OER). In this study, operando soft X-ray absorption spectroscopy (SXAS) is used to explore the electronic structure of Co3O4 under OER for the first time. The defect-rich Co3O4 (D-Co3O4) has a Co2.45+ state with Co2+ at both octahedral (Oh) and tetrahedral (Td) sites and Co3+ at Oh, whereas Co3O4 has Co2.6+ with Co2+ and Co3+ at Td and Oh sites, respectively. SXAS reveals that upon increasing the voltage, the Co2+ in D-Co3O4 is converted to low-spin Co3+, some of which is further converted to low-spin Co4+ most Co2+ in Co3O4 is converted to Co3+ but rarely to Co4+. When the voltage is switched off, Co4+ intermediates quickly disappear. These findings reveal Co(Oh) in D-Co3O4 can be rapidly converted to active low-spin Co4+ under operando conditions, which cannot be observed by ex situ XAS. © 2022 American Chemical Society.