Cerium oxide–ethylene glycol nanofluids with improved transport properties: Preparation and elucidation of mechanism

• Surfactant free ceria–ethylene glycol nanofluids prepared.
• Reduction in dispersion viscosity due to disturbance in intermolecular H bonding.
• Contribution of liquid layers of ethylene glycol over CeO2 to ‘k’ enhancement.

Ceria nanoparticles of diameter ranging between 30 and 50 nm were synthesized from cerous nitrate using hydroxide mediated precipitation. The synthesized powder was characterized using scanning electron microscopy and powder X-ray diffraction. Ceria–ethylene glycol nanofluids were prepared by dispersing ceria in ethylene glycol through homogenization and probe ultrasonication. The measurements of transport properties of ceria–ethylene glycol nanofluids reveal viscosity reduction and thermal conductivity enhancement over a range of nanoparticle concentration (0–1 vol%) and temperature. The well-dispersed nanoparticles interact with ethylene glycol, perturbing the intermolecular hydrogen bonds in ethylene glycol, leading to decrease in viscosity. The liquid layering on well-dispersed crystalline ceria nanoparticles contributes to temperature-dependent thermal conductivity with ~17% and 10.7% enhancement for 1 vol% nanofluid at 10 °C and 30 °C respectively.