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

This study used recovered stainless steel material (SSM) as a sacrificial metal source and substrate to underscore the environmental and economic benefits of stainless steel recycling. Using a water-based synthesis method, self-supporting multimetallic MOF crystals (FeNiBTC/SSM1/2/3/4/5) with a consistent MIL-100 structure could be synthesized in situ in a single step. This green synthesis approach not only minimizes harmful solvents but also enhances safety and scalability. These crystals demonstrated stable and promising electrocatalytic activity for the oxygen evolution reaction (OER). Recycling materials and adopting water-based methods help to conserve resources while simultaneously increasing catalytic efficiency. [Display omitted] 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.