Constructing bifunctional electrodes of FeCeO with tunable carbon decoration from waste plastics for efficient energy storage and the oxygen evolution reaction

Abstract

The rapid development of the economy and society makes energy and environmental issues increasingly prominent. How to efficiently utilize “green electricity” and recycle waste plastics is crucial to sustainable development strategies. Herein, a new strategy was proposed for recycling waste plastics to construct a bifunctional electrode material, i.e., waste plastics were used to fabricate carbon decoration on FeCeO nanoparticles to simultaneously boost electrochemical energy storage and electrocatalytic oxygen evolution reaction (OER) performance. At first, FeCeO nanoparticles were prepared by the co-precipitation method; then, waste plastics were employed to regulate carbon decoration on FeCeO nanoparticles via the chemical vapor deposition (CVD) method. Detailed characterization studies revealed that FeCeO with carbon decoration included abundant crystal phases of metallic Ce, CeC₂, CeO₂, metallic Fe, FeC, and Fe₃C, providing diverse active sites for electrochemical energy storage and the electrocatalytic OER. Moreover, the carbon decoration exhibited a unique slender, filamentous, hollow structure, as well as very high crystallinity and a high graphitization degree, creating a conductive network and promoting electron transfer. Consequently, FeCeO with carbon decoration achieved excellent electrochemical and electrocatalytic performance: (1) a specific capacity of 1131 F g⁻¹ at 1 A⁻¹ g, and 640 F g⁻¹ at a high current density of 50 A g⁻¹ in 6 M KOH electrolyte; (2) an overpotential of 297 mV at 100 mA cm⁻², which was 55 mV lower than that of commercial RuO₂ (352 mV), and excellent long-term (100 h) stability at a high current density of 200 mA cm⁻² in 1 M KOH electrolyte.