Free-sustaining Three-dimensional S235 Steel-based Porous Electrocatalyst for Highly Efficient and Durable Oxygen Evolution

TL;DR

This study develops a durable, efficient 3D porous steel-based electrocatalyst for oxygen evolution, demonstrating high activity and stability in alkaline and neutral conditions, with potential for low-cost energy applications.

Contribution

It introduces a simple surface modification method to enhance steel S235's electrocatalytic performance for oxygen evolution, combining high efficiency, stability, and low-cost materials.

Findings

Low overpotential of 326 mV at 10 mA/cm²

High Faradaic efficiency of over 82%

Stable operation in neutral pH conditions

Abstract

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.