Synthesis of yttrium doped nanocrystalline ZnO and its photocatalytic activity in methylene blue degradation

Yttrium doped zinc oxide was prepared by microwave irradiation of Y (NO3)3·6H2O and Zn(NO3)2·4H2O as precursors, in ethanol-water medium. Highly polar ethanol-water medium (30/70, v/v) with hexamine and urea assist the formation of ZnO nuclei very rapidly in a specific fashion. Furthermore, Y3+ ions infiltration into Zn(OH)2 precipitate was facilitated by microwaves (2.45 GHz, 950 W). Yttrium doped nanocrystalline ZnO (ZnO-99 and ZnO-95) was formed with 1 and 5 mol% yttrium precursor. The powder was morphologically characterized with XRD, DLS, SEM and TEM. Photocatalytic activity of microwave treated Y3+ doped ZnO was tested by studying the oxidation of methylene blue solution in a batch reactor. The studies showed that the catalytic reaction followed second order kinetics. Based on the results obtained from photocatalytic studies, efficiencies of various ZnO samples were found to be in this order: ZnO-A > ZnO-99 > ZnO-95 > ZnO-R that is, Y3+ doped ZnO was not as effective as commercial undoped ZnO. However, ZnO-95 had shown better stability, antiphotocorrosive nature and reusability among the samples tested in this study.