TY - JOUR
T1 - Laser Fragmentation-Induced Defect-Rich Cobalt Oxide Nanoparticles for Electrochemical Oxygen Evolution Reaction
AU - Yu, Mingquan
AU - Waag, Friedrich
AU - Chan, Candace K.
AU - Weidenthaler, Claudia
AU - Barcikowski, Stephan
AU - Tüysüz, Harun
N1 - Funding Information:
This work was financially supported by IMPRS-RECHARGE and MAXNET Energy consortium of Max Planck Society, and Collaborative Research Center SFB/TRR247 (C1 and C5, Project number: 388390466) funded by the Deutsche Forschungsgemeinschaft (DFG). C.K.C acknowledges the Alexander von Humboldt Foundation for a Humboldt Research Fellowship. S. Palm, H. Bongard, and A. Schlüter are acknowledged for EDX analysis and microscopy images. We gratefully thank J. N. Büscher and S. Gallus for conducting XPS and synchrotron measurements.
Publisher Copyright:
© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.
PY - 2020/2/7
Y1 - 2020/2/7
N2 - Sub-5 nm cobalt oxide nanoparticles are produced in a flowing water system by pulsed laser fragmentation in liquid (PLFL). Particle fragmentation from 8 nm to 4 nm occurs and is attributed to the oxidation process in water where oxidative species are present and the local temperature is rapidly elevated under laser irradiation. Significantly higher surface area, crystal phase transformation, and formation of structural defects (Co2+ defects and oxygen vacancies) through the PLFL process are evidenced by detailed structural characterizations by nitrogen physisorption, electron microscopy, synchrotron X-ray diffraction, and X-ray photoelectron spectroscopy. When employed as electrocatalysts for the oxygen evolution reaction under alkaline conditions, the fragmented cobalt oxides exhibit superior catalytic activity over pristine and nanocast cobalt oxides, delivering a current density of 10 mA cm−2 at 369 mV and a Tafel slope of 46 mV dec−1, which is attributed to a larger exposed active surface area, the formation of defects, and an increased charge transfer rate. The study provides an effective approach to engineering cobalt oxide nanostructures in a flowing water system, which shows great potential for sustainable production of active cobalt catalysts.
AB - Sub-5 nm cobalt oxide nanoparticles are produced in a flowing water system by pulsed laser fragmentation in liquid (PLFL). Particle fragmentation from 8 nm to 4 nm occurs and is attributed to the oxidation process in water where oxidative species are present and the local temperature is rapidly elevated under laser irradiation. Significantly higher surface area, crystal phase transformation, and formation of structural defects (Co2+ defects and oxygen vacancies) through the PLFL process are evidenced by detailed structural characterizations by nitrogen physisorption, electron microscopy, synchrotron X-ray diffraction, and X-ray photoelectron spectroscopy. When employed as electrocatalysts for the oxygen evolution reaction under alkaline conditions, the fragmented cobalt oxides exhibit superior catalytic activity over pristine and nanocast cobalt oxides, delivering a current density of 10 mA cm−2 at 369 mV and a Tafel slope of 46 mV dec−1, which is attributed to a larger exposed active surface area, the formation of defects, and an increased charge transfer rate. The study provides an effective approach to engineering cobalt oxide nanostructures in a flowing water system, which shows great potential for sustainable production of active cobalt catalysts.
KW - electrocatalysis
KW - metal oxides
KW - nanostructures
KW - oxygen evolution reaction
KW - structural defects
UR - http://www.scopus.com/inward/record.url?scp=85077857720&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85077857720&partnerID=8YFLogxK
U2 - 10.1002/cssc.201903186
DO - 10.1002/cssc.201903186
M3 - Article
C2 - 31756030
AN - SCOPUS:85077857720
SN - 1864-5631
VL - 13
SP - 520
EP - 528
JO - ChemSusChem
JF - ChemSusChem
IS - 3
ER -