Facile microwave-assisted synthesis of Cr2O3 nanoparticles with high near-infrared reflection for roof-top cooling applications

Hebbar, Deepak N and Choudhari, KS and Santhosh, C and Kulkarni, Suresh D (2019) Facile microwave-assisted synthesis of Cr2O3 nanoparticles with high near-infrared reflection for roof-top cooling applications. Journal of Alloys and Compounds, 785. pp. 747-753. ISSN 0925-8388

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Abstract

Microwave-assisted solution synthesis was employed for the preparation of Cr2O3 nanoparticles using Cr(acac)3 and ethylene glycol. The optimum conditions for the completion of the reaction forming a green precipitate (yield-95%) were: irradiation for 40e60 min at 220 C solution temperature. The asprepared sample was barely crystalline; annealing in air at above 300 C formed nanocrystalline Cr2O3, as shown by X-ray diffraction (XRD). High-resolution transmission electron microscopy (HRTEM) of the “700 C sample” confirmed the well-crystallised Cr2O3 formation with ~37 nm average size. The asprepared powder (bluish-green) showed high near-infrared (NIR) reflectance, whereas the annealed samples showed bright-green reflectance, whose International Commission on Illumination L*a*b* (CIE L*a*b*) values shifted towards the green region. The higher Dq/B value (3.76), suggested that Cr3þ lies in a strong crystal field. Stainless steel blocks covered with the as-prepared (intermediate) material reduced heating under sunlight by 5 C, indicating its suitability as an easily prepared tile coating for roof-top applications. The annealed samples are found suitable as an anti-dazzling coating for automobile windscreens and rear-view mirrors

Item Type: Article
Uncontrolled Keywords: Cr2O3 nanoparticles; Microwave-assisted synthesis; Oxide materials; Ceramics; Chemical synthesis
Subjects: Departments at MU > Atomic Molecular Physics
Depositing User: KMC Library
Date Deposited: 23 Mar 2019 06:17
Last Modified: 23 Mar 2019 06:17
URI: http://eprints.manipal.edu/id/eprint/153502

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