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Fabrication and Electrocatalytic Evolution of Alkali-Free CoNb2O6 Thin Films for Water Oxidation via Polyoxoniobates

De, Avik ; Rambaran, Mark A. LU and Ohlin, C. André (2024) In ACS Applied Energy Materials 7(19). p.8333-8341
Abstract

Fabrication of CoNb2O6 thin films was possible through spin-coating an alkali-free, aqueous solution of a polyoxoniobate ([Nb10O28]6-, Nb10) and a cobalt nitrate (Co(NO3)2), followed by annealing. The results showed that depending on the calcination conditions, minor phases of unreacted Co3O4 and β-Nb2O5 may form alongside the columbite CoNb2O6 phase. However, optimizing the calcination conditions can lead to the formation of single-phase orthorhombic columbite CoNb2O6. The optimal annealing temperature was evaluated by analysis of the powders made from the same... (More)

Fabrication of CoNb2O6 thin films was possible through spin-coating an alkali-free, aqueous solution of a polyoxoniobate ([Nb10O28]6-, Nb10) and a cobalt nitrate (Co(NO3)2), followed by annealing. The results showed that depending on the calcination conditions, minor phases of unreacted Co3O4 and β-Nb2O5 may form alongside the columbite CoNb2O6 phase. However, optimizing the calcination conditions can lead to the formation of single-phase orthorhombic columbite CoNb2O6. The optimal annealing temperature was evaluated by analysis of the powders made from the same solution annealed at different temperatures. The calcination temperature has been determined to have a significant impact on the phase purity of the CoNb2O6. Furthermore, the powders and thin films exhibited superior catalytic activity and stability toward water oxidation, with a low overpotential and a high current density. Fabrication of these thin films by the use of simple aqueous solutions, rather than moisture-sensitive precursors (NbCl5 or Nb(OC2H5)5) or energy-intensive methods (sputter deposition/laser ablation), fosters environmentally benign and sustainable options for various thin-film-based applications. This work provides a promising avenue for the development of efficient, green and noble-metal-free electrocatalyst thin films for water oxidation.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CoNbO, microwave synthesis, oxide, polyoxometalate, polyoxoniobate, thin film, water oxidation
in
ACS Applied Energy Materials
volume
7
issue
19
pages
9 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85205919739
ISSN
2574-0962
DOI
10.1021/acsaem.4c00840
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2024 The Authors. Published by American Chemical Society.
id
853e4a56-1da6-438d-906a-54b3f5895b44
date added to LUP
2024-10-16 16:22:55
date last changed
2025-04-04 15:26:59
@article{853e4a56-1da6-438d-906a-54b3f5895b44,
  abstract     = {{<p>Fabrication of CoNb<sub>2</sub>O<sub>6</sub> thin films was possible through spin-coating an alkali-free, aqueous solution of a polyoxoniobate ([Nb<sub>10</sub>O<sub>28</sub>]<sup>6-</sup>, Nb<sub>10</sub>) and a cobalt nitrate (Co(NO<sub>3</sub>)<sub>2</sub>), followed by annealing. The results showed that depending on the calcination conditions, minor phases of unreacted Co<sub>3</sub>O<sub>4</sub> and β-Nb<sub>2</sub>O<sub>5</sub> may form alongside the columbite CoNb<sub>2</sub>O<sub>6</sub> phase. However, optimizing the calcination conditions can lead to the formation of single-phase orthorhombic columbite CoNb<sub>2</sub>O<sub>6</sub>. The optimal annealing temperature was evaluated by analysis of the powders made from the same solution annealed at different temperatures. The calcination temperature has been determined to have a significant impact on the phase purity of the CoNb<sub>2</sub>O<sub>6</sub>. Furthermore, the powders and thin films exhibited superior catalytic activity and stability toward water oxidation, with a low overpotential and a high current density. Fabrication of these thin films by the use of simple aqueous solutions, rather than moisture-sensitive precursors (NbCl<sub>5</sub> or Nb(OC<sub>2</sub>H<sub>5</sub>)<sub>5</sub>) or energy-intensive methods (sputter deposition/laser ablation), fosters environmentally benign and sustainable options for various thin-film-based applications. This work provides a promising avenue for the development of efficient, green and noble-metal-free electrocatalyst thin films for water oxidation.</p>}},
  author       = {{De, Avik and Rambaran, Mark A. and Ohlin, C. André}},
  issn         = {{2574-0962}},
  keywords     = {{CoNbO; microwave synthesis; oxide; polyoxometalate; polyoxoniobate; thin film; water oxidation}},
  language     = {{eng}},
  number       = {{19}},
  pages        = {{8333--8341}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{ACS Applied Energy Materials}},
  title        = {{Fabrication and Electrocatalytic Evolution of Alkali-Free CoNb<sub>2</sub>O<sub>6</sub> Thin Films for Water Oxidation via Polyoxoniobates}},
  url          = {{http://dx.doi.org/10.1021/acsaem.4c00840}},
  doi          = {{10.1021/acsaem.4c00840}},
  volume       = {{7}},
  year         = {{2024}},
}