RTFM, RTPL and photocatalytic activity of CeO2/ZrO2 nanocomposites

• Published in: Chinese journal of physics (Taipei) 2017-12, Vol.55 (6), p.2588-2596
• Main Authors: Usharani, S., Rajendran, V.
• Format: Article
• Language: English
• Subjects: CeO2/ZrO2; F centers; Oxygen vacancies; Photocatalyst; RTFM; RTPL
• ISSN: 0577-9073
• DOI: 10.1016/j.cjph.2017.11.005

•Oxygen vacancies of both CeO2 and ZrO2 nanostructures are main cause for RTFM.•RTPL studies revealed the strong emission in UV and visible region due to excitons and F centers.•By varying the pH the crystallite size can be controlled.•High degradation achieve under UV light rather than visible light. CeO2/ZrO2 nanocomposites were synthesized by the co-precipitation method using different pH values such as 4.5, 5.5 and 6.5. The XRD results confirmed the presence of the tetragonal and monoclinic structure of ZrO2 and cubic fluorite structure of CeO2, and further this result divulged the average grain size of the samples, such as 25.2, 17.2 and 16.3 nm prepared at pH 4.5, 5.5 and 6.5. Nanomaterials with optical and ferromagnetic properties open the window for multifunctional devices. The VSM analysis indicated the RTFM of CeO2/ZrO2 nanocomposites in all the pH values, which can be associated with the oxygen vacancies of both CeO2 and ZrO2. Room temperature photoluminescence studies revealed that CeO2/ZrO2 nanocomposites contain high intense peaks in the UV region which is ascribed to the nearest band edge emission of the excitons and visible emission region that were possibly due to F centers. The band gap energies of the samples prepared for different pH 4.5, 5.5 and 6.5 values obtained by the tauc plots of (αhυ)2 versus (hυ) curve are 3.02, 3.3 and 3.35 eV respectively. The CeO2/ZrO2 nanocomposites at pH 6.5 was evaluated for their ability to degrade methylene blue (MB) dye solution under visible and UV light irradiation. The TEM images show that the CeO2/ZrO2 nanocomposites produced nanosheets (pH 4.5) and spherical nanoparticles (pH 5.5, 6.5).