Facile anodic fabrication of porous Ni–Fe oxide active layers on 304 stainless steel for efficient oxygen evolution reaction

The development of low-cost and high-efficiency electrocatalytic oxygen evolution reaction (OER) electrodes is crucial for improving the efficiency of hydrogen production via electrolysis. This paper reports a facile strategy for constructing a porous and slit-like Ni-Fe composite oxide active layer on 304 stainless steel substrates via anodization. The resultant self-supporting electrode exhibits outstanding OER performance, delivering a low overpotential of merely 303 mV at a current density of 10 mA·cm -2 and a Tafel slope of approximately 72.5 mV dec -1 , which is 50 mV lower than that of the commercial RuO 2 -IrO 2 electrode. Furthermore, the electrode exhibits excellent stability during a 24-hour constant-current test. This study provides a promising strategy for fabricating high-performance and low-cost self-supporting OER electrodes. • A facile anodization strategy was developed to directly construct a porous Ni–Fe composite oxide oxygen evolution active layer on 304 stainless steel substrates. • The resultant self-supporting electrode exhibits outstanding OER catalytic activity, which outperforms the commercial RuO₂-IrO₂ catalyst. • The as-fabricated electrode demonstrates exceptional stability, with no obvious performance degradation observed after a 24-hour chronoamperometric test.