Synthesis and nanofluid application of silver nanoparticles decorated graphene

In the present work we describe a novel synthesis procedure for silver decorated functionalized hydrogen induced exfoliated graphene (Ag/HEG) and preparation of nanofluids using this material. Further, thermal conductivity and convective heat transfer studies are carried out for these nanofluids. A simple chemical reduction method is implemented to synthesize uniformly coated Ag/HEG and characterized by different experimental techniques. Ag/HEG is used for making nanofluids considering the high thermal conductivity of graphene and silver nanoparticles. Ag/HEG has been dispersed in deionized water and ethylene glycol using ultrasonic agitation and proper dispersion is achieved without any surfactant. Thermal conductivity and heat transfer studies on Ag/HEG dispersed nanofluids show an enhancement in the corresponding values compared to the base fluid. The level of enhancement depends on the volume fraction and temperature at which the measurement is performed. Ag/HEG dispersed deionized water based nanofluid shows an enhancement of similar to 25% for 0.05% volume fraction at 25 degrees C. Similarly, the heat transfer coefficient of Ag/HEG based nanofluids also shows a large enhancement compared to the base fluid. The synthesized nanofluid is stable for more than three months.