Increasing water pollution poses a serious threat to both humankind and animals in the current situation. Low cost optical especially photocatalytic material is of utmost relevance to improve situation and meet the global energy demand with little environmental damage. The aim of this study is to develop low-cost low temperature reproducible method to synthesize multifunctional material suitable for degradation of a very dangerous water contaminant dye under visible light exposure. A semiwet chemical route was used to synthesize a multifunctional Bi12GeO20 compound suitable for photocatalytic activity for the degradation of Rhodamine B (RhB) dye under visible light exposure. Bi12GeO20 (BGO) ceramic with polycrystalline structure was prepared successfully e using a low temperature chemical process. X-ray powder diffraction reveals that single-phase BGO ceramic was formed. Nanosized BGO ceramic particles that had been stabilized, XRD and TEM to showed particle sizes in the 60–10 nm range. Due to the favorable band gap (2.72 eV) and the sillenite type Bi12GeO20 exhibits strong photocatalytic activity for the degradation of Rhodamine B (RhB) dye under visible light exposure.
In this manuscript, We have reported the synthesis and characterization of Mg-doped and un-doped BCTO ceramic (Bi2/3Cu3-xMgxTi4O12, x=0, 0.05, 0.1 and 0.2) sintered at 1173 K for 8 h, which have been prepared by the semi-wet route. The Single-phase formation of ceramic was approved by the XRD pattern. The Microstructural properties were studied by TEM. The samples were characterized by dielectric and impedance spectroscopic properties. The dielectric constant (εr) was calculated to be 3024 for BCTO ceramics at 423 K and 100Hz. The tangent loss (tan δ) value was calculated to be 0.45 for BCTO ceramic at 423 K and 10 kHz. The internal Barrier Layer Capacitance (IBLC) mechanism was responsible for the high value of the dielectric constant.. It was observed from Impedance studies that there was the existence of the Maxwell-Wagner form of relaxation in the ceramics. In the temperature range 300-500 K, the Bi2/3Cu3-xMgxTi4O12 (where x=0, 0.05, 0.1, 0.2) ceramic follows Arrhenius behavior with an almost single slope. Pervoskite material plays a significant role in the biosensing field like DNA hybridization. This research provided a newtype and promising perovskite for the development of efficient biosensors.
Polarity is very important in developing materials with colossal dielectric. To meet the demands for the tunable devices and high dielectric parallel plate capacitors, several perovskites such as CaCu3Ti4O12 (CCTO), La2/3Cu3Ti4O12 (LCTO) Pr2/3Cu3Ti4 O12 (PCTO) and several other materials of this class have been studied all over the world. Detailed studies showed that results vary a lot based on processing methods, such as powder vs. multi crystals and single crystals. In spite of great progress in processing, low resistivity and process driven variables in properties remain a big hurdle for its applications as a dielectric capacitor. We observed that dielectric values are significantly changed when these materials are exposed to chemicals and biological agents. We used parallel plate capacitor design for making chemical and biological sensors from CCTO member of this group. The data indicated huge difference in the dielectric and resistivity of the exposed samples.
Zinc doped titanium oxide (Ti1-xZnxO2, x=0.05) abbreviated as Ti0.95 Zn0.05O2 (TZO) ceramic was synthesized by semiwet route using aqueous solution of zinc acetate dihydrate and solid titanium dioxide as starting materials. The single phase formation of the TZO ceramic sintered at 900 °C for 8 h was confirmed by powder X-ray diffraction (XRD) analysis. The lattice parameters obtained by Retvield refinement were found to be a=b= 4.609 Å, c= 2.967Å and α=β= γ= 90 ° with space group P 42/m n m confirmed the rhombic structure of TZO ceramic. The average particle size of the TZO ceramic observed by TEM analysis was found to be 84 nm. The surface morphologies and roughness parameters of TZO ceramic were observed by atomic force microscopy (AFM) analysis. The value of dielectric constant (ε′) and tangent loss (tan δ) of the TZO ceramic were found to be 230 and 0.2, respectively at 100 Hz and 498 K.
There are several mechanisms which have been proposed for the existence of colossal dielectric constant in the class of perovskite calcium copper titanate (CaCu3Ti4O12 or CCTO) materials. Researches indicate that existence of twinning parallel to (100) (001) and (010) planes causes planar defects and causes changes in local electronic structure. This change can cause insulating barriers locally which contribute to the large dielectric values irrespective of processing. The combination of insulating barriers, defects and displacements caused by twinning have been attributed to the generation of large dielectric constant in CCTO. To examine some of these arguments some researchers replaced Ca with other elements and evaluated this concept. In this study we present the synthesis and characterization of Ga2/3Cu3Ti4O12-xNx (GCTON) material. This provides both distortion due to atomic size difference and defects due to insertion of nitrogen. The morphology of the compound was determined to show that processing has tremendous effect on the dielectric values. The resistivity of GCTON was several order higher than CCTO and dielectric constant was higher than 10,000.
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