Influence of iron doping on tetravalent nickel content in catalytic oxygen evolving films.

Li, Nancy; Bediako, D Kwabena; Hadt, Ryan G; Hayes, Dugan; Kempa, Thomas J; von Cube, Felix; Bell, David C; Chen, Lin X et al. · Proc Natl Acad Sci U S A · 2017

basic_science · Level V

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Abstract

Iron doping of nickel oxide films results in enhanced activity for promoting the oxygen evolution reaction (OER). Whereas this enhanced activity has been ascribed to a unique iron site within the nickel oxide matrix, we show here that Fe doping influences the Ni valency. The percent of Fe<sup>3+</sup> doping promotes the formation of formal Ni<sup>4+</sup>, which in turn directly correlates with an enhanced activity of the catalyst in promoting OER. The role of Fe<sup>3+</sup> is consistent with its behavior as a superior Lewis acid.