Synthesis of α-Fe2O3 nano-rod/sheet: Volumetric and electrical conductivity properties of their nanofluids

Physico-chemical properties of synthesized α-Fe2O3 nano-rods/sheets using the co-precipitation method and 3-sulfanylpropane-1,2-diol as a capper and shape-directing agent were studied. The synthesized nanomaterials were characterized using UV–visible, powder X-ray diffraction (pXRD), High-resolution transmission electron microscopy (HR-TEM), Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), and Thermogravimetry analysis (TGA) techniques. Characterized nanomaterials revealed the formation of the pure rhombohedral crystal structure of nano-rod having a diameter of 33 nm and length of 76 nm, apart from the formation of nano-sheets with a diameter of 86 nm. An average absorption maximum (λmax) of 396.5 nm was observed. The properties of the prepared α-Fe2O3 nanofluids were investigated from 298.15 K to 338.15 K temperatures. The density of nanofluids was observed to increase with an increase in mole fraction of α-Fe2O3 nano-rods/sheets but decreases with an increase in temperature. Excess molar volume data shows positive and negative values revealing van der Waals interactions, packing effect, and hydrogen bonding forces. This volumetric property has revealed a significant impact of intermolecular interactions present in nanofluids on various thermodynamic properties. Results revealed an increment in electrical conductivity with an increase in volume fraction. A maximum enhancement of 2195 % was observed for 0.000728 mol fraction at 338.15 K in ethylene glycol/double-distilled water nanofluid. These electromagnetic nanofluids have great scope for application as smart electrolytes in electronic devices.