Nonylphenol polybenzoxazines-derived nitrogen-rich porous carbon (NRPC)-supported g-C₃N₄/Fe₃O₄ nanocomposite for efficient high-performance supercapacitor application

In this work, a straightforward and scalable method was used to generate nitrogen-rich porous carbon (NRPC), which was then incorporated with a graphitic carbon nitride and magnetite (g-C₃N₄/Fe₃O₄) nanocomposite, fabricated with Fe₃O₄ nanoparticles as an eco-friendly and economically viable component. The fabricated NRPC/g-C₃N₄/Fe₃O₄ nanocomposite was applied as an electrode in supercapacitor applications. The synthesized NRPC/g-C₃N₄/Fe₃O₄ nanocomposite, NRPC, g-C₃N₄, and Fe₃O₄ were characterized by analytical and morphological analyses. The spherically shaped Fe₃O₄ nanoparticles were analyzed by field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). The specific surface area of NRPC/g-C₃N₄/Fe₃O₄ was determined to be 479 m² g⁻¹. All the crosslinked composites showed exceptional electrochemical performance and exhibited a pseudo-capacitance behaviour. In comparison to the Fe₃O₄ and g-C₃N₄/Fe₃O₄ electrodes, the NRPC/g-C₃N₄/Fe₃O₄ electrode showed a lower charge-transfer resistance and higher capacitance. The prepared NRPC/g-C₃N₄/Fe₃O₄ electrode exhibited the highest specific capacitance of 385 F g⁻¹ at 1 A g⁻¹ compared to Fe₃O₄ (112 F g⁻¹) and g-C₃N₄/Fe₃O₄ (150 F g⁻¹). Furthermore, the cycling efficiency of NRPC/g-C₃N₄/Fe₃O₄ remained at 94.3% even after 2000 cycles. The introduction of NRPC to g-C₃N₄/Fe₃O₄ improved its suitability for application in high-performance supercapacitors.