Excellent Electrochemical Oxygen Production from Ultrafine Nanoparticles of Manganese Ferrite Spinel Derived from Spent Primary Battery

The development of novel, cost‐effective, and energy‐efficient electrode materials for electrochemical oxygen production utilizing waste batteries is a “two‐birds in one‐stone” approach for fulfilling oxygen demands as well as addressing environmental challenges. Keep this in mind: in this present study, valuable manganese and iron precursors have been successfully recovered from spent zinc‐carbon batteries using a simple and effective hydrometallurgy method. These iron and manganese precursor undergoes hydrothermal treatment at 120 °C to stabilize ultrafine spherical nanoparticles (15–20 nm) of manganese ferrite (MnFe 2 O 4 ) spinel. The developed ultrafine MnFe 2 O 4 nanoparticles show superior electrocatalytic activity toward the electrochemical oxygen evolution reaction (OER) in alkaline media with a lower Tafel slope (62 mA cm −2 ), lower overpotential ( η 10) = 320 mV, and extended electrochemical stability. Mechanistic insights of the oxygen evolution process, along with the impact of roughness factor ( R f ), wettability, and electrochemical surface area on OER performance, have also been investigated.