From Food Waste to Efficient Bifunctional Nonprecious Electrocatalyst.

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Chemistry

Background:

• Developing efficient and cost-effective electrocatalysts is crucial for energy conversion technologies.
• Graphitic nanocarbons derived from waste offer a sustainable platform for catalyst development.
• Iron oxide nanoparticles are promising catalytic materials but often suffer from aggregation and low conductivity.

Purpose of the Study:

• To synthesize a novel bifunctional electrocatalyst using graphitic nanocarbons from food waste and iron oxide nanoparticles.
• To investigate the synergistic effects between graphitic nanocarbons and iron oxide nanoparticles on catalytic performance.
• To evaluate the electrocatalytic activity and stability for oxygen reduction and evolution reactions.

Main Methods:

• Graphitic nanocarbons were produced from food waste via biomethane cracking.
• Potassium-intercalated graphitic nanocarbons were dissolved to obtain reduced graphene sheets.
• Iron oxide nanoparticles were synthesized and homogeneously dispersed onto the reduced graphene framework.
• Electrocatalytic performance was assessed using techniques like cyclic voltammetry and chronoamperometry.

Main Results:

• A composite electrocatalyst with well-dispersed 2-5 nm iron oxide nanoparticles on a conductive nanocarbon framework was successfully synthesized.
• The iron oxide/nanocarbon electrocatalyst exhibited an overpotential of ~1 V for the oxygen reduction reaction (ORR) at 10 mA cm⁻².
• The catalyst showed remarkable activity for the oxygen evolution reaction (OER) with an overpotential of ~0.4 V at 10 mA cm⁻², comparable to RuO₂ and IrO₂.

Conclusions:

• The synergistic combination of graphitic nanocarbons and iron oxide nanoparticles yields a highly efficient bifunctional electrocatalyst.
• This sustainable electrocatalyst, derived from food waste, offers a promising alternative to precious metal catalysts for energy applications.
• The developed material demonstrates versatility, high activity, and stability, paving the way for practical applications in catalysis.