Interfacial synergy in NiCo2O4@g-C3N4 heterostructures for advanced supercapacitors and selective organic pollutant degradation

Abstract

The development of efficient electrode materials is an important research area in advanced energy-storage technologies. In this study, a NiCo2O4@g-C3N4 heterostructure was synthesized via a facile hydrothermal method and investigated as a bifunctional material for supercapacitor and photocatalytic applications. The structural, morphological, and chemical properties of the synthesized materials were analysed using various characterization techniques. Electrochemical studies revealed that the NiCo2O4@g-C3N4 hybrid electrode exhibited enhanced charge-storage performance, delivering a high specific capacitance of 1776.4 F g−1 at 2.4 A g−1 in 3 M KOH electrolyte. The fabricated asymmetric supercapacitor demonstrated good energy-storage capability, retaining 94.48% of its capacitance after 6500 charge–discharge cycles, and produced a stable voltage sufficient to illuminate a red LED. Furthermore, the NiCo2O4@g-C3N4 nanocomposite exhibited superior visible-light-driven photocatalytic activity, achieving 96.17% degradation of methylene blue (MB) and 96.19% degradation of crystal violet (CV) within 150 min. The enhanced bifunctional performance is attributed to the synergistic interaction between NiCo2O4 and g-C3N4, which facilitates charge transfer, promotes efficient charge separation, and improves photocatalytic activity. These findings demonstrate the potential of NiCo2O4@g-C3N4 as a promising material for multifunctional energy-storage and photocatalytic applications.