An effort was made to synthesize nanostructured TiO(2) via sol-gel technique to obtain a 100% rutile polymorph of nanostructured TiO(2). The sol-gel synthesis technique was suitably modified by incorporating ultrasound to study the effect of cavitation on the phase transformation, crystallite size, crystallinity and morphological (scanning electron microscopy) properties of the obtained nano-TiO(2). It was observed that using ultrasound, yield of the nano-TiO(2) was improved from 86.35% to 95.078%. The phase transformation of anatase-to-rutile of TiO(2) was studied for both (ultrasound assisted and conventional) the processes. Complete phase transformation of the TiO(2) was observed as expected with and without the use of ultrasound but the marked reduction in the required calcination temperature for obtaining 100% phase transformation with ultrasound was the major achievement in the present study, leading to 70% energy savings during calcination.

Nanostructured zirconium dioxide was synthesized from zirconyl nitrate using both conventional and ultrasound assisted precipitation in alkaline medium. The synthesized samples were calcinated at temperatures ranging from 400°C to 900°C in steps of 100°C. The ZrO(2) specimens were characterized using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The thermal characteristics of the samples were studied via Differential Scanning Calorimetry-Thermo-Gravimetry Analysis (DSC-TGA). The influence of the calcination temperature on the phase transformation process from monoclinic to tetragonal to cubic zirconia and its consequent effect on the crystallite size and % crystallinity of the synthesized ZrO(2) was studied and interpreted. It was observed that the ultrasound assisted technique helped to hasten to the phase transformation and also at some point resulted in phase stabilization of the synthesized zirconia.

A flexible technique is developed using hydrochloric acid to modify the redox reaction between potassium permanganate and sodium nitrite in order to grow ultrafine α-MnO 2 nanorods, hydrothermally. The nanorods grown were 10-40 nm diameters in range. Not any crack, fissure, imperfection or dislocation is observed in the nanorods suggesting it to be finely ordered. Structure, phase and purity of as developed nanorods were determined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Energydispersive X-ray spectroscopy. Peseudocapacitance of α-MnO 2 nanorods was tested using a three electrode system. Considerably very high pseudocapacitance value of 643.5 F/g at 15 A/g current density was calculated from the galvanostatic discharge current measurement.Also excellent cyclability is observed with high retention of 90.5% after 4000 cycles. Highly uniform and confined morphology of the nanorods helps smooth the electron dynamics between electrode/electrolyte interfaces resulting in superior performance. Most importantly, the use of potassium ferricyanide as redox additive to KOH electrolyte was proved to be quite effective as it provides extra redox couple [Fe(CN) 6 ] 3− /[Fe(CN) 6 ] 4− which helps in further smoothening of electron transition thereby resulting in considerably superior pseudocapacitive performance.

Titanium dioxide was successfully synthesized by utilizing sol-gel technique modified by incorporation of ultrasound as a reaction aid. The effect of amplitude of irradiation (power input varied from 19.9 to 80.8 W) on % Rutile, % yield, % crystallinity, crystallite size and morphological (scanning electron microscopy) properties of the obtained nano-TiO(2) was studied. Calcination temperatures of all the samples were kept constant at 750 degrees C. With increasing ultrasonic irradiation amplitude it is observed that the values of % Rutile (after calcination) increased and reached a peak value after which further increase in amplitude resulted in a decrease in the % Rutile. A similar trend was observed in the case of % crystallinity and % yield of the reaction. On the basis of these results an optimum operating ultrasonic irradiation amplitude for the reaction has been suitably established.