Optical, photocatalytic and bactericidal properties of Zn1−xLaxO and Zn1−xMgxO nanostructures prepared by a sol–gel method

Zn1-xLaxO and Zn1-xMgxO (x = 0-0.10) nanostructures were synthesised by a sol-gel method and the nanopowders were structurally and thermally characterised by XRD, SEM, TEM and TGA/DTA. The La-doped nanostructures were spherical while the Mg-doped ZnO nanoparticles changed from spherical to nanorod shaped as the Mg concentration increased. The photocatalytic properties of the Zn1-xLaxO and Zn1-xMgxO (x = 0-0.10) nanostructures were evaluated by the photodegradation of an aqueous methylene blue solution. Enhanced photocatalytic activity was observed for La-doped ZnO nanoparticles due to the formation of electron-hole pairs, whereas the photocatalytic activity was reduced in MgO-doped ZnO nanoparticles. Both La-doped and MgO-doped ZnO nanoparticles exhibited better antibacterial activity against S aureus and E coli than undoped ZnO nanoparticles because of their increased surface area.