Different nanoscale objects of CuO have been synthesized by a simple chemical route where the Cu(OH) 2 nanostructures were first synthesized by the alkaline hydrolysis of Cu(NO 3 ) 2 ?3H 2 O using NaOH as a base and the synthesized precipitate was subsequently annealed at a temperature of 130 uC. The alkaline content (pH) of the solutions during the hydrolysis process was varied to tailor the morphologies and dimensions of the nanostructures, consequently a series of fascinatingly shaped nanostructures, e.g. seeds, ellipsoidal, rods and leaves were obtained. Topographical characteristics along with the mechanism behind the structural variation have been rationalized by XRD, FTIR, SEM and HRTEM investigations. Optical performance of these samples provided simultaneous emission in the visible bands of blue, green, yellow and red, which were correlated to the size, shape and structural defects of these nano-scaled objects. The toxicity of these nanostructured materials were also put into perspective and it was found that the leaf shaped particles were the most toxic among the various shapes of nano-CuO. Finally the synthesized particles, when applied as nanofluids (water medium) showed their ability to enhance the thermal conductivity of water to a noticeable degree (above 40%) at high temperatures, even at very small concentrations, bespeaking their applicability in cooling fluids.

VO2 (B) nanorods with average width ranging between 50-100 nm are synthesized via a hydrothermal method and the post hydrothermal treatment drying temperature is found to be influential in their overall phase and growth morphology evolution. The nanorods with unusually high optical bandgap for a VO2 material are effective in enhancing the thermal performance of ethylene glycol nanofluids over a wide temperature range as is indicated by the temperature dependent thermal conductivity measurements. Humidity and LPG sensors fabricated using the VO2 (B) nanorods bear testament to their efficient sensing performance, which can be partially attributed to the mesoporous nature of the nanorods.

NiO nanostructures were synthesized via a simple wet chemical solution method with varying calcination temperatures. The synthesized nanostructures were characterized by XRD, TG/DSC, FT-IR and high-resolution electron microscopy techniques. The nanostructures revealed dependence of particle size, stoichiometry, optical band gap and luminescence intensity on calcination temperatures. The materials exhibited efficient electrochemical properties with decent capacitance values. Ethylene-glycol-based nanofluids of these nanoparticles registered excellent thermal conductivity enhancement of 59-69% in the room temperature region and 125% enhancement at higher temperatures (80 ° C), establishing NiO to be a top-draw contender for high-performance heat transfer fluids.