Electroactive heterojunctions of iron-based compounds in oxygen evolution reaction—Insight into synergy and mechanism.

• Low-temperature (250 °C), Environmentally Friendly Methodology addresses the challenges of low catalytic activity and stability associated with Oxygen Evolution Reaction (OER) catalysts. • Synergistic Interplay of three different Fe-based heterojunctions (Fe 3 O 4 , Fe 3 C, and FeNi 3), enhancing the stability of the catalyst and facilitating efficient charge transfer in OER. • Optimized Catalyst Performance of Fe/Ni_3.0h with an overpotential of 310 mV at 10 mA/cm2, Tafel slope of 37 mV/dec, and stability retaining ∼98.8 %. • Comprehensive Mechanism Revealed through Advanced Analyses through Ex-Situ XRD and Mössbauer spectroscopy analyses. This research addresses the inherent challenges of low catalytic activity and stability often associated with Oxygen Evolution Reaction (OER) catalysts. We designed composites with outstanding electrocatalytic performance. The methodology is characterized by low-temperature operation and environmentally friendly substrates. We have successfully fostered a synergistic interplay between Fe and oxygen, carbon and nickel, respectively. Fabricated material composed of three different heterojunctions triggered the stability of the catalyst and facilitated efficient charge transfer in OER. Our optimized catalyst (Fe/Ni_3.0h), emerges as a promising candidate for practical applications, exhibiting an overpotential of 310 mV, a Tafel slope of 37 mV/dec, and a potential retention of 98.8 % which is a 50 % lower drop in respect to commercial RuO 2. Therefore, our approach underlines the substantial influence of conductive Fe-based materials: FeNi 3 , Fe 3 C, and Fe 3 O 4 on OER performance with revealed comprehensive mechanism via ex-situ XRD and Mössbauer spectroscopy analyses. [Display omitted] [ABSTRACT FROM AUTHOR]