Sustainable oxygen evolution catalysis: Water-based fabrication of FeNi-MIL-100 on recycled stainless steel substrates.

Abstract

The anodic oxygen evolution reaction (OER) process is essential in new technologies such as water electrolysis and metal-air batteries. However, it often exhibits suboptimal efficiency and delayed kinetics. This study presents a novel and new design for the fabrication of homogeneous FeNiBTC/SSM (SSM = stainless steel material) with tunable crystalline properties by a self-sacrificial and in situ synthesis from a recycled stainless steel substrate. The modified stainless steel template enhances the material's properties compared to the original mesh substrate and its structure can be attributed to the typical MIL-100 (Material of Institute Lavoisier) structure, which is a hierarchically structured, highly chemically stable material formed by FeO6 octahedral clusters around a single shared oxygen anion. The as-synthesized FeNiBTC/SSM4 catalyst exhibited excellent electrocatalytic performance for OER, as indicated by its small Tafel slope (74.5 mV dec^-1), low overpotential (η₁₀ 223.7 mV), and high current retention (95.4 %) after a stability test lasting 45 h. The study demonstrates the development of water-based and self-sustaining MOF electrocatalysts for the oxygen evolution reaction in a simple process, along with a novel method for reusing renewable resources.