Three-dimensional Ni foam supported NiCoO2@Co3O4 nanowire-on-nanosheet arrays with rich oxygen vacancies as superior bifunctional catalytic electrodes for overall water splitting

Earth abundant transition metal oxide (EATMO)-based bifunctional catalysts for overall water splitting are highly desirable, but their performance is far from satisfactory due to low intrinsic activities of EATMOs toward electrocatalysis of both oxygen and hydrogen evolution reactions and poor elect...

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Bibliographic Details
Published in:Nanoscale 2023-09, Vol.15 (34), p.14068-14080
Main Authors: Pan, Yixiang, Wang, Xiaoyan, Lin, Hua, Xia, Qinghua, Maoxiang Jing, Yuan, Weiyong, Li, Chang Ming
Format: Article
Language:English
Subjects:
Arrays
Catalysts
Cobalt oxides
Electrodes
Electron transfer
Epitaxial growth
Heterostructures
Hydrogen evolution reactions
Metal foams
Nanosheets
Nanowires
Noble metals
Oxygen
Surface defects
Transition metal oxides
Water splitting
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Summary:Earth abundant transition metal oxide (EATMO)-based bifunctional catalysts for overall water splitting are highly desirable, but their performance is far from satisfactory due to low intrinsic activities of EATMOs toward electrocatalysis of both oxygen and hydrogen evolution reactions and poor electron transfer and transport capabilities. A three-dimensional (3-D) Ni-foam-supported NiCoO2@Co3O4 nanowire-on-nanosheet heterostructured array with rich oxygen vacancies has been synthesized, showing OER activity superior to most reported catalysts and even much higher than Ru and Ir-based ones and HER activity among the highest reported for non-noble-metal-based catalysts. The excellent activities are ascribed to the highly dense, ultrathin nanowire arrays epitaxially grown on an interconnected layered nanosheet array greatly facilitating electron transfer and providing numerous electrochemically accessible active sites and the high content of oxygen vacancies on nanowires greatly promoting OER and HER. When adopted as bifunctional electrodes for overall water splitting, this heterostructure shows an overvoltage (at 10 mA cm−2) lower than most reported electrolyzers and high stability. This work not only creates a 3-D EATMO-based integrated heterostructure as a low-cost, highly efficient bifunctional catalytic electrode for water splitting, but also provides a novel strategy to use unique heteronanostructures with rich surface defects for synergistically enhancing electrocatalytic activities.
ISSN:2040-3364
2040-3372
DOI:10.1039/d3nr02302h