Evaluation on La2O3 garlanded ceria heterostructured binary metal oxide nanoplates for UV/ visible light induced removal of organic dye from urban wastewater

A low energy bandgap between Ce3+ and Ce4+ states in cerium oxides, high oxygen mobility and high oxygen storage capacity are the properties that qualify them to be the most widely used heterogeneous catalysts. This present work is an account of studies that were carried out on the synthesis and catalytic properties of pure CeO2, CeO2/La2O3 based binary metal oxide nanostructures prepared by the hydrothermal method. Our results revealed that the synthesis temperature and pressure during hydrothermal reactions played a critical role in controlling the shape, size, oxygen vacancy, and low temperature reducibility in CeO2 based nanostructures. In addition, OH− ion concentration was found to play an important role in engineering the lattice constants and oxygen vacancy defects. The present report demonstrated that the hydrothermal synthesis is a facile one step approach for the preparation of compositionally homogeneous cerium based binary metal oxide nanostructures, in which CeO2/La2O3 mixed oxides have a superior low-temperature oxygen release capability compared to pure CeO2. We have also demonstrated that the nanomaterials are proved to have higher catalytic performance at low temperatures as compared to pure ceria nanoparticles. Keywords: CeO2:La2O3, Heterogeneous catalysts, Electron microscopy, Photocatalytic activity, RhB dy

Elucidation of photocatalysis, photoluminescence and antibacterial studies of ZnO thin films by spin coating method

The ZnO thin films have been prepared by spin coating followed by annealing at different temperatures like 300 °C, 350 °C, 400 °C, 450 °C, 500 °C & 550 °C and ZnO nanoparticles have been used for photocatalytic and antibacterial applications. The morphological investigation and phase analysis of synthesized thin films well characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Photoluminescence (PL), Transmission Electron Microscopy (TEM) and Raman studies. The luminescence peaks detected in the noticeable region between 350 nm to 550 nm for all synthesized nanosamples are associated to the existence of defects of oxygen sites. The luminescence emission bands are observed at 487 nm (blue emission), and 530 nm (green emission) at the RT. It is observed that there are no modification positions of PL peaks in all ZnO nanoparticles. In the current attempt, the synthesized ZnO particles have been used photocatalytic and antibacterial applications. The antibacterial activity of characterized samples was regulated using different concentrations of synthesized ZnO particles (100 μg/ml, 200 μg/ml, 300 μg/ml, 400 μg/ml, 500 μg/ml and 600 μg/ml) against gram positive and gram negative bacteria (S. pnemoniae, S. aureus, E. coli and E. hermannii) using agar well diffusion assay. The increase in concentration, decrease in zone of inhibition. The prepared ZnO morphologies showed photocatalytic activity under the sunlight enhancing the degradation rate of Rhodamine-B (RhB), which is one of the common water pollutant released by textile and paper industries