Hexagonal nanoplates of NiO/CoO/Fe2O3 composite acting as an efficient photocatalytic and electrocatalytic water oxidation catalyst

Abstract

A unique hexagonal sheet-shaped NiO/CoO/Fe₂O₃ composite with irregularly shaped nanoparticles was fabricated for the first time through a simple co-precipitation and hydrothermal method. The NiO/CoO/Fe₂O₃ composite was characterized by numerous techniques (TEM, HRTEM, PXRD, EDX, ICP-AES, BET, and XPS) to confirm its structure and composition. This structure of the NiO/CoO/Fe₂O₃ composite may enhance the photocatalytic and electrocatalytic performance for water oxidation. Compared with NiO, CoO and Fe₂O₃, the NiO/CoO/Fe₂O₃ composite exhibits a lower overpotential and a much smaller Tafel slope of 49 mV dec⁻¹ for water oxidation. At the same time, the composite possesses beneficial ferromagnetic properties and superior stability; thus, it can be used repeatedly without any loss in activity.