Europium (Eu3+) - doped ZnO nanostructures: Synthesis, characterization, and photocatalytic, chemical sensing and preliminary assessment of magnetic properties

Abstract

We have successfully synthesized single-phase wurtzite hexagonal ZnO:Eu3+ (1, 5 and 10 mol %) nanoparticles via facile co-precipitation method. The samples have been characterized by powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), fourier transform infrared (FTIR) and UV–visible spectroscopy. Change in optical band gap is explained by invoking the existence 4f electronic states of Eu3+ in the band gap of ZnO. Photocatalytic performance of these samples for degradation of methyl orange (MO), rhodamine B (Rh B) and picric acid (PA) under UV illumination is found to be 3–3.5 times higher than pure ZnO. However, 5 mol% doping exhibited the highest catalytic efficiency. This sample was also highly sensitive and selective for PA, and the limit of detection was: 1.790 μM, 1.140 μM and 1.751 μM for 1, 5 and 10 mol% Eu3+ doped ZnO samples respectively. Finally, all samples behave weak ferromagnetically at room temperature, but a systematic increase in the ferromagnetic-like response is noticed with Eu3+ concentration, despite finding no evidence of secondary magnetic phases; EuO and Eu2O3 from XRD measurements. Conceivably, the observed ferromagnetic order is attributed to defect induced f7– ferromagnetism. Indeed, low concentration of Eu3+ dopant is found to be more significant, as reported by different groups.