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Enhancement of Oxygen Evolution Activity of Nickel Oxyhydroxide by Electrolyte Alkali Cations
Author(s) -
Garcia Amanda C.,
Touzalin Thomas,
Nieuwland Celine,
Perini Nickson,
Koper Marc T. M.
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201905501
Subject(s) - oxygen evolution , chemistry , electrolyte , nickel , inorganic chemistry , dielectric spectroscopy , alkali metal , electrochemistry , raman spectroscopy , catalysis , oxygen , impurity , electrode , organic chemistry , physics , optics
Herein, the effect of the alkali cation (Li + , Na + , K + , and Cs + ) in alkaline electrolytes with and without Fe impurities is investigated for enhancing the activity of nickel oxyhydroxide (NiOOH) for the oxygen evolution reaction (OER). Cyclic voltammograms show that Fe impurities have a significant catalytic effect on OER activity; however, both under purified and unpurified conditions, the trend in OER activity is Cs + > Na + > K + > Li + , suggesting an intrinsic cation effect of the OER activity on Fe‐free Ni oxyhydroxide. In situ surface enhanced Raman spectroscopy (SERS), shows this cation dependence is related to the formation of superoxo OER intermediate (NiOO − ). The electrochemically active surface area, evaluated by electrochemical impedance spectroscopy (EIS), is not influenced significantly by the cation. We postulate that the cations interact with the Ni−OO − species leading to the formation of NiOO − −M + species that is stabilized better by bigger cations (Cs + ). This species would then act as the precursor to O 2 evolution, explaining the higher activity.