Waste cotton fabric derived porous carbon containing Fe₃O₄/NiS nanoparticles for electrocatalytic oxygen evolution

Developing low-cost, active and durable electrocatalysts for oxygen evolution reaction (OER) is an urgent task for the applications such as water splitting and rechargeable metal-air battery. Herein, this work reports the fabrication of a metal and hetero atom co-doped fibrous carbon structure derived from cotton textile wastes and its use as an efficient OER catalyst. The free-standing fibrous carbon structure, fabricated with a simple two-step carbonization process, has a high specific surface area of 1796 m²/g and a uniform distribution of Fe₃O₄/NiS nanoparticles (Fe₃O₄/NiS@CC). The composite exhibits excellent OER performance with an onset potential of 1.44 V and a low overpotential of 310 mV at the current density of 10 mA/cm² in a 1.0 M KOH solution, which even surpass commercial RuO₂ catalyst. Additionally, this ternary catalyst shows remarkable long-term stability without current density loss after continuous operation for 26 h. It can be believed that the outstanding OER performance is attributed to the synergistic effect between the iron oxides and nickel sulphides, as well as the micro-meso porous carbon structure. This study demonstrates a new strategy to use conventional textile materials to prepare highly efficient electrocatalysts; it also provides a simple approach to turn textile waste into valuable products.