Structural transformation of highly active metal–organic framework electrocatalysts during the oxygen evolution reaction
Author(s)
Zhao, S
Tan, C
He, CT
An, P
Xie, F
Jiang, S
Zhu, Y
Wu, KH
Zhang, B
Li, H
Zhang, J
Chen, Y
Liu, S
Dong, J
Tang, Z
Griffith University Author(s)
Year published
2020
Metadata
Show full item recordAbstract
Metal–organic frameworks (MOFs) are increasingly being investigated as electrocatalysts for the oxygen evolution reaction (OER). Despite their promising catalytic activity, many fundamental questions concerning their structure−performance relationships—especially those regarding the roles of active species—remain to be answered. Here we show the structural transformation of a Ni0.5Co0.5-MOF-74 during the OER by operando X-ray absorption spectroscopy analysis and high-resolution transmission electron microscopy imaging. We suggest that Ni0.5Co0.5OOH0.75, with abundant oxygen vacancies and high oxidation states, forms in situ ...
View more >Metal–organic frameworks (MOFs) are increasingly being investigated as electrocatalysts for the oxygen evolution reaction (OER). Despite their promising catalytic activity, many fundamental questions concerning their structure−performance relationships—especially those regarding the roles of active species—remain to be answered. Here we show the structural transformation of a Ni0.5Co0.5-MOF-74 during the OER by operando X-ray absorption spectroscopy analysis and high-resolution transmission electron microscopy imaging. We suggest that Ni0.5Co0.5OOH0.75, with abundant oxygen vacancies and high oxidation states, forms in situ and is responsible for the high OER activity observed. The ratio of Ni to Co in the bimetallic centres alters the geometric and electronic structure of as-formed active species and in turn the catalytic activity. Based on our understanding of this system, we fabricate a Ni0.9Fe0.1-MOF that delivers low overpotentials of 198 mV and 231 mV at 10 mA cm−2 and 20 mA cm−2, respectively.
View less >
View more >Metal–organic frameworks (MOFs) are increasingly being investigated as electrocatalysts for the oxygen evolution reaction (OER). Despite their promising catalytic activity, many fundamental questions concerning their structure−performance relationships—especially those regarding the roles of active species—remain to be answered. Here we show the structural transformation of a Ni0.5Co0.5-MOF-74 during the OER by operando X-ray absorption spectroscopy analysis and high-resolution transmission electron microscopy imaging. We suggest that Ni0.5Co0.5OOH0.75, with abundant oxygen vacancies and high oxidation states, forms in situ and is responsible for the high OER activity observed. The ratio of Ni to Co in the bimetallic centres alters the geometric and electronic structure of as-formed active species and in turn the catalytic activity. Based on our understanding of this system, we fabricate a Ni0.9Fe0.1-MOF that delivers low overpotentials of 198 mV and 231 mV at 10 mA cm−2 and 20 mA cm−2, respectively.
View less >
Journal Title
Nature Energy
Note
This publication has been entered in Griffith Research Online as an advanced online version.
Subject
Environmental engineering