English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Coulometric Titration of Active Sites at Mesostructured Cobalt Oxide Spinel by Surface Interrogation Mode of Scanning Electrochemical Microscopy

Lorenz, J., Yu, M., Tüysüz, H., Harms, C., Dyck, A., & Wittstock, G. (2020). Coulometric Titration of Active Sites at Mesostructured Cobalt Oxide Spinel by Surface Interrogation Mode of Scanning Electrochemical Microscopy. The Journal of Physical Chemistry C, 124(14), 7737-7748. doi:10.1021/acs.jpcc.9b11114.

Item is

Basic

show hide
Genre: Journal Article

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Lorenz, Julian1, 2, Author
Yu, Mingquan3, Author           
Tüysüz, Harun3, Author           
Harms, Corinna1, Author
Dyck, Alexander1, Author
Wittstock, Gunther2, Author
Affiliations:
1DLR Institute of Networked Energy Systems, Carl-von-Ossietzky-Str. 15, 26129 Oldenburg, Germany, ou_persistent22              
2Chemistry Department, Carl von Ossietzky University of Oldenburg, 26111 Oldenburg, Germany, ou_persistent22              
3Research Group Tüysüz, Max-Planck-Institut für Kohlenforschung, Max Planck Society, ou_1950290              

Content

show
hide
Free keywords: -
 Abstract: Cobalt-based transition-metal oxides are promising candidates for the oxygen evolution reaction (OER). However, a complex interplay between the catalyst crystal structures and material morphologies as well as the surface reactions hampers a comprehensive understanding of the electrocatalytic OER at those materials. Here, we investigate the amount and reactivity of specific surface sites of a mesostructured cobalt oxide spinel powder by surface interrogation mode of scanning electrochemical microscopy (SI-SECM). The powder material was supplied in cavity microelectrodes and efficiently titrated with an Fe(II)-triethanolamine redox mediator generated at a gold microelectrode in an alkaline electrolyte. Thus, quantification of different surface sites was achieved, and their reactivity showed dependence on the cobalt oxidation state. Titration experiments after adjustable time delays with respect to the generation of the different surface sites indicated that these surface sites are active for the OER. Kinetic analysis revealed two pseudo-first-order decay constants that were related to fast and slow surface sites for the OER. Rate constants were determined for potentials where predominantly a mixed-valence CoIII/IV state might be present as the most active species. These results expand the great potential of the surface interrogation mode on studying the reaction kinetics of distinct surface sites for practically relevant powdered, nonprecious metal catalysts to address a highly relevant challenge in electrocatalysis.

Details

show
hide
Language(s): eng - English
 Dates: 2019-11-282020-03-162020-04-09
 Publication Status: Published in print
 Pages: 12
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1021/acs.jpcc.9b11114
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: The Journal of Physical Chemistry C
  Abbreviation : J. Phys. Chem. C
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Washington, D.C. : American Chemical Society
Pages: - Volume / Issue: 124 (14) Sequence Number: - Start / End Page: 7737 - 7748 Identifier: ISSN: 1932-7447
CoNE: https://pure.mpg.de/cone/journals/resource/954926947766