A one-step microwave synthesis using neither a template surfactant nor strong molar NaOH concentrations is reported. Well shaped nanorod and nanocube CeO2 structures were achieved in 0.5 and 4 h at a maximum irradiation of 200 W, respectively. Both nanostructures grew through different processes, they are dependent on the irradiation conditions, time and temperature. The photocatalytic water splitting evaluation of cerium oxide nanostructures was carried out using water contaminated with hydrazine and the surface "in-situ" functionalization of Cu-0 nanoparticles (CuNPs) on the surface, achieving 753 mu mol/h g of hydrogen generation. During the photocatalytic process, the "in-situ" reduction reaction (CuO -> Cu-0) occurring on the CeO2 surface promotes the electron transfer process due to the copper work function. (C) 2016 Elsevier By. All rights reserved.