Hierarchically structured Co1-X NiXO/laser-induced porous graphene nanohybrids for supercapacitors and dye degradation

Abstract

Developing efficient and multifunctional materials is necessary to address global challenges like the energy crisis and environmental pollution. This study introduces a sustainable and scalable Co1-xNixO/ laser induced porous graphene (CoNiO/PG) nanohybrids, synthesized via a chemical co-precipitation method and a laser induced photothermal conversion process for dual applications in electrochemical supercapacitors and photocatalytic dye degradation. The CoNiO/PG nanohybrids demonstrated outstanding electrochemical supercapacitor performance, achieving a high specific areal capacitance of 3.53 mF cm-2 at 0.51 mA cm-2. A symmetric pouch cell fabricated using the nanohybrid delivered a specific areal capacitance of 2.17 mF cm-2 at 0.7 mA cm-2, with an energy density of 1.2 mWh cm-2 and a power density of 0.35 mW cm-2, retaining 89 % of its initial capacitance over 2000 cycles. Simultaneously, the nanohybrids displayed remarkable photocatalytic activity, achieving 94 % degradation of 5 ppm methylene blue dye within 120 min under UV-visible light. The enhanced photocatalytic activity arises from synergistic effects, including efficient electron-hole separation, reducing recombination losses, and the generation of reactive oxygen species, particularly hydroxyl radicals (center dot OH), as supported by photoluminescence and radical scavenger studies. The laser induced porous graphene structure enhanced charge transfer and catalytic efficiency, while the CoNiO nanoflakes provided active sites and facilitated pseudocapacitance. Furthermore, the CoNiO/PG photocatalyst exhibited excellent recyclability, retaining its photocatalytic efficiency over five consecutive cycles with negligible performance loss. This work underscores the potential of metal oxide/graphene-nanohybrids as scalable and cost-effective solution for advanced energy storage and environmental remediation, paving the way for sustainable technologies.