N-doped NiFeO_x/N-CNT catalysts with surface oxygen vacancies for efficient oxygen evolution and water treatment

We report a one-step vacuum annealing synthesis of nitrogen-doped NiFeOx nanoparticles encapsulated in nitrogen-doped carbon nanotubes (N-NiFeOx/N-CNT). This core–shell structure, rich in surface oxygen vacancies, demonstrates outstanding electrocatalytic performance for the oxygen evolution reaction (OER), with low overpotentials of 218 mV and 282 mV at 50 and 100 mA cm⁻², respectively, and excellent stability. Additionally, the material achieves 94.5 % removal of crystal violet (CryV) dye from water within 5 min. The synergistic effects of N-doping, oxygen vacancies, and enhanced hydrophilicity are identified as key contributors to the dual catalytic and adsorption performance. This work presents a cost-effective approach for developing multifunctional catalysts for sustainable energy and water treatment applications.