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Three-dimensional Ni 4 O 4 -cubane metal–organic framework as a high-performance electrocatalyst for urea oxidation
The urea oxidation reaction (UOR) is considered to be a replacement of the sluggish anodic oxygen evolution reaction (OER) in overall water-splitting. A three-dimensional (3D) nickel-containing metal–organic framework {[Ni II 2 (pdaa)(OH) 2 (H 2 O)] n (MOF 1) (where, H 2 pdaa = 1,4-phenylene diaceti...
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Published in: | RSC advances 2022-10, Vol.12 (44), p.28388-28394 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The urea oxidation reaction (UOR) is considered to be a replacement of the sluggish anodic oxygen evolution reaction (OER) in overall water-splitting. A three-dimensional (3D) nickel-containing metal–organic framework {[Ni
II
2
(pdaa)(OH)
2
(H
2
O)]
n
(MOF 1) (where, H
2
pdaa = 1,4-phenylene diacetic acid) was investigated as a robust and highly efficient electrocatalyst for the UOR. MOF 1 comprised 1D nickel(
ii
) chains crosslinked through Ni
4
O
4
cubane units to form a 3D extended network. Dangling Ni⋯OH
−
groups were exposed in the MOF 1 structure, and could act as active catalytic centers for the UOR. MOF 1 required a very small onset potential of 1.18 V for urea oxidation in KOH (1 M) and urea (0.33 M) and had a low Tafel slope of 38.8 mV dec
−1
(in contrast to 1.84 V for the oxygen evolution reaction). The overpotential required to attain a catalytic current density of 10 mA cm
−2
was 1.24 V, which is much lower than that for many materials. Controlled potential electrolysis, powder X-ray diffraction, and X-ray photoelectron spectroscopy affirmed the physicochemical integrity of the catalyst over a 17 h test reaction. This work not only addresses the problem of urea contamination, it also helps to utilize it in an energy-conversion process. |
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ISSN: | 2046-2069 2046-2069 |
DOI: | 10.1039/D2RA05145A |