Hierarchical CuCo-Oxide/N-Doped Graphene-CNTs 3D Composite Material for High-performance Energy Storage and Environmental Sustainability
Mayakrishnan Gopiraman, V. Ramkumar, Bharathi Arumugam, Cadiam Mohan Babu, Madhappan Santhamoorthy, Azeem Ullah, Ji Ha Lee, Seong‐Cheol Kim, Ick Soo Kim
Abstract
Abstract Developing cost-effective, high-performance materials for energy storage, environmental remediation, and electrocatalysis is crucial for sustainable technologies. Here, we report a novel CuCo-oxide/N-GCNT composite, synthesized via a scalable, solvent-free method, and evaluated for supercapacitors, catalytic reduction of 4-nitrophenol, HMF oxidation, and water splitting. The composite exhibited a high specific capacitance of 162.63 F/g at 1 A/g, an energy density of 22.5 Wh/kg, and a power density of 1267.3 kW/kg, with 88.08% retention after 10,000 cycles, demonstrating excellent supercapacitor stability. In environmental catalysis, the material enabled complete 4-nitrophenol reduction in 3 min with a pseudo-first-order rate constant (89.72 × 10 −2 s −1 ). It also achieved 98.7% HMF conversion and 68.6% FDCA yield using 70% t-BuOOH as an oxidant. As a bifunctional electrocatalyst, CuCo-oxide/N-GCNT delivered overpotentials of 258 mV (OER) and 185 mV (HER) at 100 mA/cm 2 , with Tafel slopes of 56.5 mV/dec (OER) and 84.0 mV/dec (HER). The enhanced performance is attributed to synergistic bimetallic interactions, high porosity, and uniform active site dispersion. This study establishes CuCo-oxide/N-GCNT as a sustainable, high-performance alternative to noble-metal catalysts for next-generation energy and environmental applications. Graphical Abstract