Oxygen vacancy induced photoluminescence properties and enhanced photocatalytic activity of ferromagnetic ZrO2 nanostructures on methylene blue dye under ultra-violet radiation

Room temperature ferromagnetic (RTFM) ZrO2 nanostructures with tetragonal (t-ZrO2) and monoclinic (m-ZrO2) phases were synthesized by sol-gel method. The photoluminescence (PL) feature of the synthesized samples was investigated using 300 nm excitation wavelength. The decrease of saturation magnetization (Ms) and intensity of emission band at higher calcinations temperature is attributed to the reduction of density of oxygen vacancies in the ZrO2 matrix. The variation of Ms with calcinations temperature follows the same trend as intensity of emission band varies. It further confirms that the presence of RTFM and decrease in emission band intensity is caused due change in density of oxygen vacancies with calcinations temperature. The photocatalytic activity of ZrO2 nanostructures has been investigated on methylene blue (MB) dye as function of particle size under ultra-violet (UV) radiation with 365 nm wavelength. The ZrO2 nanostructures with smaller particle size are found to be efficient for photodegradation of MB dye. Oxygen vacancies are found to be the main cause for enhanced photocatalytic activity of ZrO2 nanostructures. (C) 2015 Elsevier B.V. All rights reserved.