Investigation of the photocatalytic properties of Er3+ i Yb3+ doped strontium gadolinium oxide nanopowder

Abstract

This research aimed to investigate for the first-time photocatalytic degradation of methylene blue over SrGd2 O4 powders co-doped with constant Er3+ (0.5 at%) and different Yb3+ (1, 2.5 and 5 at%) concentrations. The samples were successfully prepared via sol-gel assisted combustion method. X-ray Powder Diffraction pattern proved that all samples crystallize as a pure orthorhombic SrGd2 O4 phase. Scanning Electron Microscopy was used for morphology characterization and it revealed the existence of porous agglomerated round-shaped particles. Energy Dispersive X-ray Spectroscopy showed the presence of dopant ions and even distribution of all constituting elements. For energy band calculation, UV-VIS Diffuse Reflectance Spectroscopy was performed and a value of 4.3 eV was obtained, as well as the four additional values from the bands at lower energies. Photocatalytic degradation of methylene blue was monitored using UV-VIS Absorption Spectroscopy. The obtained results were promising since after 4 h of exposure to the simulating Sun irradiation, more than 50% of the starting dye concentration was mineralized.