Al2O3 Intercalated into Reduced Graphene Oxide as a Potential Nanofluid with Improved Thermal Properties for Heat Transfer Applications

Abstract

Using nanofluids has gained significant recognition within renewable and sustainable energy. Incorporating a limited quantity of solid nanoparticles possessing enhanced thermal conductivity into conventional fluid can yield significant advancements in heat transfer applications. The present investigation concentrates on the extensive synthesis of Al₂O₃ nanoparticles and reduced graphene oxide (rGO) using waste tyres as a basis for nanocomposite nanofluids. The objective is to enhance the thermal characteristics of the composite, thereby establishing it as a promising nanofluid. The synthesis of Al₂O₃ nanoparticles, reduced graphene oxide (rGO), and Al₂O₃/rGO composites was conducted using the sonication-assisted sol-gel method, enhanced Hummer method, and sonochemical procedures. Additional two-step preparation procedures were employed to produce highly stable nanofluids based on Al₂O₃/rGO composites. These methods involved varying the concentration ratios of 1:0.5, 1:1, 1:1.5, and 1:2 wt.%. To validate their authenticity, the materials underwent various characterizations, including XRD, FESEM, and Particle size examination. The stability examination of all the weight percentages was conducted using the sedimentation photograph method. The results showed exceptional stability for up to 8 weeks from the preparation date without any surfactant. The occurrence can be attributed to combining Al₂O₃, rGO, and Al₂O₃/rGO nanocomposite.