ZnO modified by urea–hydrogen peroxide adduct as photocatalyst for 2-propanol photooxidation in the gas phase under different irradiations

Zinc oxide nanoparticles were synthesized via sol–gel process using zinc acetate dihydrate, ethanol and oxalic acid as precursor, solvent and complexing agent, respectively. Urea-hydrogen peroxide (UHP) and urea were added as modification agents. UHP played, simultaneously, the role of nitrogen precursor and oxygen donor. Structural, morphological, textural and optical properties of zinc oxide samples were studied using XRD, SEM, BET, UV–Vis–DRS and Raman techniques. The XRD patterns and Raman spectroscopy results showed that the products consisted of ZnO and revealed that nitrogen was doped in the lattice of ZnO. SEM images revealed the occurrence of agglomeration and aggregation of ZnO nanoparticles. The photocatalytic activity of ZnO samples was estimated based on the photooxidation of 2-propanol in gaseous phase under UV and solar irradiations. Under both UV and solar irradiations, ZnO doped with UHP showed higher photocatalytic activity in comparison with bare ZnO and ZnO doped with only urea. The results showed that increasing the crystallite size has a direct effect on the improvement of the photocatalytic activity of ZnO.