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Ultrasmall Dispersible Crystalline Nickel Oxide Nanoparticles as High‐Performance Catalysts for Electrochemical Water Splitting
Author(s) -
Fominykh Ksenia,
Feckl Johann M.,
Sicklinger Johannes,
Döblinger Markus,
Böcklein Sebastian,
Ziegler Jürgen,
Peter Laurence,
Rathousky Jiri,
Scheidt ErnstWilhelm,
Bein Thomas,
FattakhovaRohlfing Dina
Publication year - 2014
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201303600
Subject(s) - materials science , non blocking i/o , nickel oxide , overpotential , catalysis , chemical engineering , nanoparticle , oxide , nanocrystal , nickel , water splitting , electrochemistry , electrocatalyst , inorganic chemistry , nanotechnology , photocatalysis , electrode , metallurgy , organic chemistry , chemistry , engineering
Ultrasmall, crystalline, and dispersible NiO nanoparticles are prepared for the first time, and it is shown that they are promising candidates as catalysts for electrochemical water oxidation. Using a solvothermal reaction in tert ‐butanol, very small nickel oxide nanocrystals can be made with sizes tunable from 2.5 to 5 nm and a narrow particle size distribution. The crystals are perfectly dispersible in ethanol even after drying, giving stable transparent colloidal dispersions. The structure of the nanocrystals corresponds to phase‐pure stoichiometric nickel( ii ) oxide with a partially oxidized surface exhibiting Ni( iii ) states. The 3.3 nm nanoparticles demonstrate a remarkably high turn‐over frequency of 0.29 s –1 at an overpotential of g = 300 mV for electrochemical water oxidation, outperforming even expensive rare earth iridium oxide catalysts. The unique features of these NiO nanocrystals provide great potential for the preparation of novel composite materials with applications in the field of (photo)electrochemical water splitting. The dispersed colloidal solutions may also find other applications, such as the preparation of uniform hole‐conducting layers for organic solar cells.