Effect of cerium ions in Ce-Doped ZnO nanostructures on their photocatalytic and picric acid chemical sensing

Nanostructured ZnO doped with different Ce precursor concentrations (1, 5 and 10 mol%) has been prepared via co-precipitation method and tested for their photocatalytic and chemical sensing performances toward methyl orange (MO) and picric acid (PA) chemicals, respectively. After addition of Ce dopant, the spherical morphology of ZnO particles changed to a cone-like structure and exhibited the single-phase wurtzite structure, except for the 10 mol % dopant concentration. Blue-shift was detected in 5 mol% Ce doping, and this was found to be the optimum concentration for achieving the maximum dye degradation and sensing performances. The 5 mol% Ce doped ZnO expressed the complete MO degradation under UV light illumination, but the decrease in MO degradation with 10 mol% Ce doped ZnO was suggested to suppress the Ce³⁺ character in the sample. Facile redox couple Ce³⁺/Ce⁴⁺ appeared to improve the charge separation of Ce-doped ZnO upon UV illumination, forming the basis for release of O_2, leading to increased catalytic and PA sensing performances.