  A novel oxygen evolution reaction (OER) catalyst (3D S235-P steel) based on
steel S235 substrate has been successfully prepared via a facile one-step
surface modification. The standard Carbon Manganese steel was phosphorizated
superficially leading to the formation of a unique 3D interconnected nanoporous
surface with high specific area which facilitates the electrocatalytically
initiated oxygen evolution reaction. The prepared 3D S235-P steel exhibits
enhanced electrocatalytic OER activities in alkaline regime confirmed by a low
overpotential ({\eta}=326 mV at j=10 mA cm-2) and a small Tafel slope of 68.7
mV dec-1. Moreover, the catalyst was found to be stable under long-term usage
conditions functioning as oxygen evolving electrode at pH 13 as evidenced by
the sufficient charge to oxygen conversion rate (Faradaic efficiency: 82.11%
and 88.34% at 10 mA cm-2 and 5 mA cm-2, respectively). In addition, it turned
out that the chosen surface modification renders steel S235 into an OER
electrocatalyst sufficiently and stable to work in neutral pH condition. Our
investigation revealed that the high catalytic activities are likely to stem
from the generated Fe/(Mn) hydroxide/oxo-hydroxides generated during the OER
process. The phosphorization treatment is therefore not only an efficient way
to optimize the electrocatalytic performance of standard Carbon-Manganese
steel, but also enables for the development of low cost and abundant steels in
the field of energy conversion.
