CBD grown pure and Ce-doped ZnO nanorods: Comparison of their photocatalytic degrading efficiencies on AR88 azo dye under visible light irradiation

Abstract

A seed-mediated approach was utilized in growing of pure and cerium-doped ZnO nanorods via a low -temperature (similar to 95 degrees C) chemical bath deposition (CBD) method. The aqueous solutions with different Ce molar ratios (Ce/(Ce + Zn), which were equal to 0, 0.01, 0.05, 0.1 or 0.2) were prepared. An excess amount of cerium ions (>= 0.1 in the present study) caused the formation of a new phase, identified as CeO2. Cerium doping induces lattice strains due to the difference in radius of the anions. With doping, the 2 theta angle of X-ray diffraction (XRD) peaks slightly shifted towards lower values. Inserting cerium atoms brings about decrease, as well, in the band gap, which was confirmed by the redshifts at the absorption edges in their UV-vis spectra. In addition, the photoluminescence (PL) spectra of the samples were measured at room temperature revealed the enhanced visible emission intensities from the Ce-doped nanorods. This indicates the formation of defect levels below the conduction band. Finally, the photocatalytic degrading efficiencies of the samples on Acid Red 88 (AR88) azo dye were determined under visible light irradiation. The highest degradation rate was measured for the doped samples prepared using the CBD solution with the Ce/(Ce + Zn) ratio equal to 0.01.