N. Sabari Arul

Fabrication of CeO2/Fe2O3 composite nanospindles for enhanced visible light driven photocatalysts and supercapacitor electrodes

Hybrid CeO2/Fe2O3 composite nanospindles (CNSs) are synthesized by a simple and cost effective co-precipitation method. CeO2/Fe2O3 CNSs used as an efficient recyclable photocatalyst for degrading Eosin Yellow (EY) dye under visible light irradiation possess a high degradation rate of 98% after 25 min. The estimated electrical energy efficiency of CeO2/Fe2O3 CNSs shows the consumption of less energy (6.588 kW h m−3 per order) in degrading EY. Besides, the CeO2/Fe2O3 CNS exhibits a specific capacitance of 142.6 F g−1 at a scan rate of 5 mV s−1. Moreover, the composite displays an excellent capacitance retention of 94.8% after 1000 cycles. This newly designed CeO2/Fe2O3 CNS with enhanced visible light-driven photocatalytic activity and good supercapacitive cycling stability has great potential for use in wastewater treatment and energy storage applications.

Synthesis of CeO 2 nanorods with improved photocatalytic activity: comparison between precipitation and hydrothermal process

The main purpose of this article is to examine the surface free cerium oxide (CeO2) nanostructures prepared by different methods. CeO2 nanoparticles and nanorods were prepared by two different methods including precipitation and hydrothermal process. In precipitation process the nanoparticles were prepared at room temperature, while in hydrothermal process nanorods were prepared at high temperature. X-ray and electron diffraction analysis show the presence of CeO2. X-ray photoelectron spectroscopy (XPS) confirms the presence of CeO2 in both nanostructures. From BET, the specific surface area of nanorods (110 m2g−1) is found to be higher than nanoparticles (52 m2g−1). Also, the effect of morphology on their photodegradation of azo dye acid orange 7 (AO7) under UV–Visible light has been successfully investigated. The results show that the CeO2 nanorods synthesized by hydrothermal method have high surface area and exhibit improved performance in the photocatalytic activity.

Facile hydrothermal synthesis of CeO2 nanopebbles

Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO 2 and the average particle size estimated from the Scherrer formula was found to be 6.69 nm. X-ray absorption spectrum of CeO2 nanopebbles exhibits two main sharp white lines at 880 and 898 eV due to the spin orbital splitting of M4 and M5. Optical absorption for the synthesized CeO2 nanopebbles exhibited a blue shift (Eg = 3.35 eV) with respect to the bulk CeO2 (Eg = 3.19 eV), indicating the existence of quantum confinement effects.

Sensitivity Studies on Vacuum Deposited V2O5 Thin Films

Vanadium pentoxide thinfilms have been deposited by vacuum evaporation method and the effect of deposition temperatures on the surface morphology of the prepared sample has been analyzed. Structural and morphological were carried out on the prepared samples, using X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM). The samples deposited at elevated temperature showed nanopetal like structures on their surface which were found to be around 100-200 nm. The formation of the V2O5 phase has been confirmed through TG/DTA analysis which shows a sharp peak around 690°C corresponding to the melting point of vanadium pentoxide. The best sample was subjected to gas sensing analysis and the change in the resistance of the sensing element with respect to the test gas concentration was measured by noting down the resistance at each concentration for various time intervals. Sensitivity of the material linearly increased with different concentration of the test gas.

Room Temperature Growth of Cerium-Iron Oxide Nanorods

Cerium-iron oxide composite nanorods were synthesized by a surfactant free precipitation method. The synthesized products were characterized by XRD, FESEM, BET and TEM. Increase in the mole concentration causes the morphology of the cerium oxide to change from nanorods into nanocubes. X-ray diffraction pattern shows a diffraction peak at 28.5° corresponding to (111) reflection plane normal to c axis of a cubic fluorite structure of CeO2 and also hexagonal phase of Fe2O3 and orthorhombic phase of FeO (OH). EDAX analysis on individual nanorod conform the presences of Iron, which supports the XRD spectra. From transmission electron microscopy (TEM), the length and width of the nanorods were estimated in the range of ~100-350 nm and ~20-40 nm respectively. The Brunauer Emmett Teller (BET) analysis showed the increase in surface area for the obtained nanorods with respect to the increase in Fe concentration which in turn enhanced the formation and growth of nanorods.