Efficient Noble‐Metal‐Free γ‐Fe2O3@NiO Core–Shell Nanostructured Photocatalysts for Water Oxidation

Flowerlike noble-metal-free -Fe2O3@NiO core-shell hierarchical nanostructures have been fabricated and examined as a catalyst in the photocatalytic oxidation of water with [Ru(bpy)(3)](ClO4)(2) as a photosensitizer and Na2S2O8 as a sacrificial electron acceptor. An apparent TOF of 0.29mols(-1)m(-2) and oxygen yield of 51% were obtained with -Fe2O3@NiO. The -Fe2O3@NiO core-shell hierarchical nanostructures could be easily separated from the reaction solution whilst maintaining excellent water-oxidation activity in the fourth and fifth runs. The surface conditions of -Fe2O3@NiO also remained unchanged after the photocatalytic reaction, as confirmed by X-ray photoelectron spectroscopy (XPS).