Effect of Gd3+ doping on structural and photocatalytic properties of ZnO obtained by facile microwave-hydrothermal method

Abstract

Abstract: Gd3+-doped ZnO nanoparticles with different Gd3+ concentrations were synthesized by an eco-friendly microwave hydrothermal method. X-ray diffraction measurements confirm that the prepared nanoplates exhibit hexagonal wurtzite structure. Gd3+ doping induces lattice expansion of ZnO due to the larger ionic radius of rare earth Gd3+ in relation to Zn2+ ions. Rietveld refinement, Raman and Photoluminescence (PL) spectra confirm that Gd3+ ions were successfully inserted into ZnO lattice. The 2.0 mol% Gd3+ doped sample exhibits an increased photoluminescence intensity in comparison to that for the undoped ZnO, which is attributed to the enhance in the defect concentration due to Gd3+ doping. The photocatalytic activities of the samples were also evaluated towards UV-A induced degradation of methylene blue in aqueous solution. The highest photocatalytic activity was observed for 1.0 mol% Gd3+-doped ZnO nanoparticles (73% for methylene blue degradation within 150 min under UV–Vis irradiation). The particles size, agglomeration degree and the electronic effects due to the Gd3+ dopping seems to be the main parameters that affect the photocatalytic activity of Gd3+-doped ZnO nanoparticles. Graphical abstract: [Figure not available: see fulltext.]