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Electro-oxidation of Ni42 steel: A highly active bifunctional electrocatalyst

Schäfer, Helmut; Chevrier, Daniel M.; Zhang, Peng; Stangl, Johannes; Müller-Buschbaum, Klaus; Hardege, Jörg D.; Kuepper, Karsten; Wollschläger, Joachim; Krupp, Ulrich; Dühnen, Simon; Steinhart, Martin; Walder, Lorenz; Sadaf, Shamaila; Schmidt, Mercedes

Authors

Helmut Schäfer

Daniel M. Chevrier

Peng Zhang

Johannes Stangl

Klaus Müller-Buschbaum

Karsten Kuepper

Joachim Wollschläger

Ulrich Krupp

Simon Dühnen

Martin Steinhart

Lorenz Walder

Shamaila Sadaf

Mercedes Schmidt



Abstract

Janus type water‐splitting catalysts have attracted highest attention as a tool of choice for solar to fuel conversion. AISI Ni42 steel is upon harsh anodization converted into a bifunctional electrocatalyst. Oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are highly efficiently and steadfast catalyzed at pH 7, 13, 14, 14.6 (OER) and at pH 0, 1, 13, 14, 14.6 (HER), respectively. The current density taken from long‐term OER measurements in pH 7 buffer solution upon the electro‐activated steel at 491 mV overpotential (η) is around four times higher (4 mA cm−2) in comparison with recently developed OER electrocatalysts. The very strong voltage–current behavior of the catalyst shown in OER polarization experiments at both pH 7 and at pH 13 are even superior to those known for IrO2‐RuO2. No degradation of the catalyst is detected even when conditions close to standard industrial operations are applied to the catalyst. A stable Ni‐, Fe‐oxide based passivating layer sufficiently protects the bare metal for further oxidation. Quantitative charge to oxygen (OER) and charge to hydrogen (HER) conversion are confirmed. High‐resolution XPS spectra show that most likely γ−NiO(OH) and FeO(OH) are the catalytic active OER and NiO is the catalytic active HER species.

Journal Article Type Article
Publication Date Sep 20, 2016
Journal Advanced Functional Materials
Print ISSN 1616-301X
Electronic ISSN 1616-3028
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 26
Issue 35
Pages 6402-6417
APA6 Citation Schäfer, H., Chevrier, D. M., Zhang, P., Stangl, J., Müller-Buschbaum, K., Hardege, J. D., …Schmidt, M. (2016). Electro-oxidation of Ni42 steel: A highly active bifunctional electrocatalyst. Advanced Functional Materials, 26(35), 6402-6417. doi:10.1002/adfm.201601581
DOI https://doi.org/10.1002/adfm.201601581
Keywords Electrocatalysis; Full‐water splitting; Hydrogen evolution reaction; Oxygen evolution reaction
Publisher URL https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201601581
Related Public URLs https://arxiv.org/abs/1703.07775
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