Mesoporous Nickel Ferrites with Spinel Structure Prepared by an Aerosol Spray Pyrolysis Method for Photocatalytic Hydrogen Evolution

Submicron-sized mesoporous nickel ferrite (NiFe2O4) spheres were prepared by an aerosol spray pyrolysis method using Pluronic F127 as a structure-directing agent, and their photocatalytic performance for hydrogen (H-2) evolution was examined in an aqueous MeOH solution by visible light irradiation (lambda > 420 nm). The structure of the spherical mesoporous nickel ferrites was studied by transmission electron microscopy, powder X-ray diffraction, and N-2 adsorption desorption-desorption isotherm measurements. Mesoporous NiFe2O4 spheres of high specific surface area (278 m(2) g(-1)) with a highly crystalline framework were prepared by adjusting the amount of structure-directing agent and the calcining condition. High photocatalytic activity of mesoporous NiFe2O4 for H-2 evolution from water with methanol was achieved due to the combination of high surface area and high crystallinity of the nickel ferrites.