N,F co‐doped carbon derived from spent bleaching earth waste as oxygen electrocatalyst support

Affordable nitrogen and fluorine co‐doped carbon nanostructure was prepared from the hazardous industrial waste of edible oil refinery, spent bleaching earth (SBE), and used as raw material for obtaining high‐performance non‐noble metal bifunctional oxygen electrocatalysts. Waste SBE contains 35 % residue non‐saturated oil as a carbon source and the assistance of montmorillonite (MMT) as the template. This study converts waste SBE into a fluorine‐doped carbon nanostructure through a pyrolysis process followed by removing the aluminosilicate layers of the MMT by HF etching. Furthermore, the impregnation of the support with Co and Fe nitrates readily gives rise to N, F co‐doped carbon (NFC) electrocatalysts, as confirmed by XPS analysis. Electrochemical results evidenced that the Co‐NFC catalyst proved to be a valuable bifunctional competitor for oxygen reduction reaction and oxygen evolution reaction in alkaline media, showing activity in both reactions and superior stability compared with the Fe‐NFC catalyst in accelerated tests. This work offers a straightforward, economical, and eco‐friendly strategy for designing N, F co‐doped carbon‐based electrocatalysts for oxygen reactions in electrochemical devices.