TY - JOUR
T1 - Structural Dynamics of Ultrathin Cobalt Oxide Nanoislands under Potential Control
AU - Stumm, Corinna
AU - Bertram, Manon
AU - Kastenmeier, Maximilian
AU - Speck, Florian D.
AU - Sun, Zhaozong
AU - Rodríguez-Fernández, Jonathan
AU - Lauritsen, Jeppe V.
AU - Mayrhofer, Karl J.J.
AU - Cherevko, Serhiy
AU - Brummel, Olaf
AU - Libuda, Jörg
N1 - Publisher Copyright:
© 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/3/24
Y1 - 2021/3/24
N2 - Cobalt oxide is a promising earth abundant electrocatalyst and one of the most intensively studied oxides in electrocatalysis. In this study, the structural dynamics of well-defined cobalt oxide nanoislands (NIs) on Au(111) are investigated in situ under potential control. The samples are prepared in ultra-high vacuum and the system is characterized using scanning tunneling microscopy (STM). After transfer into the electrochemical environment, the structure, mobility, and dissolution is studied via in situ electrochemical (EC) STM, cyclic voltammetry, and EC on-line inductively coupled plasma mass spectrometry. Cobalt oxide on Au(111) forms bilayer (BL) and double-bilayer NIs (DL), which are stable at the open circuit potential (0.8 VRHE). In the cathodic scan, the cobalt oxide BL islands become mobile at potentials of 0.5 VRHE and start dissolving at potentials below. In sharp contrast to the BL islands, the DL islands retain their morphology up to much lower potential. The re-deposition of Co aggregates is observed close to the reduction potential of Co2+ to Co3+. In the anodic scan, both the BL and DL islands retain their morphology up to 1.5 VRHE. Even under these conditions, the islands do not show dissolution during the oxygen evolution reaction (OER) while maintaining their high OER activity.
AB - Cobalt oxide is a promising earth abundant electrocatalyst and one of the most intensively studied oxides in electrocatalysis. In this study, the structural dynamics of well-defined cobalt oxide nanoislands (NIs) on Au(111) are investigated in situ under potential control. The samples are prepared in ultra-high vacuum and the system is characterized using scanning tunneling microscopy (STM). After transfer into the electrochemical environment, the structure, mobility, and dissolution is studied via in situ electrochemical (EC) STM, cyclic voltammetry, and EC on-line inductively coupled plasma mass spectrometry. Cobalt oxide on Au(111) forms bilayer (BL) and double-bilayer NIs (DL), which are stable at the open circuit potential (0.8 VRHE). In the cathodic scan, the cobalt oxide BL islands become mobile at potentials of 0.5 VRHE and start dissolving at potentials below. In sharp contrast to the BL islands, the DL islands retain their morphology up to much lower potential. The re-deposition of Co aggregates is observed close to the reduction potential of Co2+ to Co3+. In the anodic scan, both the BL and DL islands retain their morphology up to 1.5 VRHE. Even under these conditions, the islands do not show dissolution during the oxygen evolution reaction (OER) while maintaining their high OER activity.
KW - cobalt oxide
KW - electrocatalysis
KW - electrochemical scanning tunneling microscopy
KW - model catalysis
KW - oxygen evolution reaction
UR - http://www.scopus.com/inward/record.url?scp=85099392570&partnerID=8YFLogxK
U2 - 10.1002/adfm.202009923
DO - 10.1002/adfm.202009923
M3 - Journal article
AN - SCOPUS:85099392570
SN - 1616-301X
VL - 31
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 13
M1 - 2009923
ER -