Europium doping effect on 3D flower-like SnO nanostructures: morphological changes, photocatalytic performance and fluorescence detection of heavy metal ion contamination in drinking water.

Pure and Eu-doped (1, 3, 5, 7 & 10 mol%) SnO nanostructures have been successfully synthesized by a facile and simple hydrothermal method. The properties of as-synthesized samples have been investigated by various analytical techniques. It was found that the morphology of as-synthesized flower-like SnO nanostructures made of intermingled small-size agglomerated nanorods can be precisely controlled by varying the Eu dopant concentration in a reasonable range. Moreover, the photocatalytic activity of SnO studied by the degradation of rhodamine-B (RhB) dye in aqueous media shows excellent performance on 10 mol% europium doping, which may be attributed to its specific morphology and larger surface area as seen from BET measurements. Furthermore, sensors based on 10 mol% Eu-doped SnO nanostructures show the highest fluorescence quenching efficiency (0.23) as compared to pure SnO and other doped samples for the lowest concentration of Cd (10 ppb) in drinking water with a Limit of Detection (LOD) as low as 7 ppb; 0.007 μg mL. The formation mechanism of Eu-doped SnO nanostructures has been discussed in detail.