Thermal and Rheological Characterization of Aqueous Nanofluids Based on Reduced Graphene Oxide

Nanofluids have become of interest in recent years thanks to their improved thermal properties, which make them especially interesting for microchannel heat sink applications. In this study, we prepared two aqueous nanofluids based on reduced graphene oxide (rGO) decorated with manganese dioxide (Mn...

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Bibliographic Details
Published in:Nanomaterials (Basel, Switzerland) Switzerland), 2022-09, Vol.12 (17)
Main Authors: Lozano-Steinmetz, Felipe, Ramírez-Navarro, María Paz, Vivas, Leonardo, Vasco, Diego A, Singh, Dinesh Pratap, Zambra-Sazo, Carlos
Format: Article
Language:English
Subjects:
Analysis
Chemical synthesis
Composite materials
Diffraction
Fluids
Graphene
Mechanical properties
Methods
Nanoparticles
Oxides
Raman spectroscopy
Structure
Thermal properties
X-rays
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Summary:Nanofluids have become of interest in recent years thanks to their improved thermal properties, which make them especially interesting for microchannel heat sink applications. In this study, we prepared two aqueous nanofluids based on reduced graphene oxide (rGO) decorated with manganese dioxide (MnO[sub.2] ) at a concentration of 0.1 wt.%. The difference between the two nanofluids was in the preparation of the reduced graphene oxide decorated with MnO[sub.2] . In the first case, the manganese salt was mixed with ascorbic acid before GO reduction with NaOH, and in the second case, the GO reduction with NaOH occurred under ascorbic acid. Ascorbic acid not only plays the role of a non-toxic and ecofriendly reducing agent but also acts as an important parameter to control the reaction kinetics. The structural, microstructural and spectral characterizations of the MnO[sub.2] /rGO nanocomposite were conducted via X-ray diffractometry (XRD), Raman spectroscopy, FT-IR, TEM, SEM and EDS analyses. Moreover, the synthesized MnO[sub.2] /rGO nanocomposites were utilized as nanofluids and their stability, thermal conductivity and rheological behaviors were studied. The thermal conductivity of the MnO[sub.2] /rGO and MnO[sub.2] AsA/rGO nanofluids was 17% and 14.8% higher than that of water for the average temperature range, respectively, but their viscosity remained statistically equal to that of water. Moreover, both nanofluids presented Newtonian behavior in the analyzed shear rate range. Therefore, both MnO[sub.2] /rGO and MnO[sub.2] AsA/rGO nanofluids are promising alternatives for use in applications with micro- and millichannel heat sinks.
ISSN:2079-4991
2079-4991
DOI:10.3390/nano12173042