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

Hebbar N. Deepak, K. S. Choudhari, S. A. Shivashankar, C. Santhosh, Suresh D. Kulkarni

Research output: Contribution to journalArticle

1 Citation (Scopus)

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 40–60 min at 220 °C solution temperature. The as-prepared 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 as-prepared 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 Cr3+ 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.

Original languageEnglish
Pages (from-to)747-753
Number of pages7
JournalJournal of Alloys and Compounds
Volume785
DOIs
Publication statusPublished - 15-05-2019

Fingerprint

Roofs
Microwaves
Nanoparticles
Cooling
Infrared radiation
Windshields
Coatings
Ethylene Glycol
Stainless Steel
Tile
High resolution transmission electron microscopy
Ethylene glycol
Powders
Automobiles
Precipitates
Stainless steel
Lighting
Irradiation
Annealing
Crystalline materials

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Cite this

@article{5f278a332c3f4d1a8b41fdd1e7bae93c,
title = "Facile microwave-assisted synthesis of Cr2O3 nanoparticles with high near-infrared reflection for roof-top cooling applications",
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 40–60 min at 220 °C solution temperature. The as-prepared 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 as-prepared 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 Cr3+ 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.",
author = "Deepak, {Hebbar N.} and Choudhari, {K. S.} and Shivashankar, {S. A.} and C. Santhosh and Kulkarni, {Suresh D.}",
year = "2019",
month = "5",
day = "15",
doi = "10.1016/j.jallcom.2019.01.254",
language = "English",
volume = "785",
pages = "747--753",
journal = "Journal of Alloys and Compounds",
issn = "0925-8388",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Facile microwave-assisted synthesis of Cr2O3 nanoparticles with high near-infrared reflection for roof-top cooling applications

AU - Deepak, Hebbar N.

AU - Choudhari, K. S.

AU - Shivashankar, S. A.

AU - Santhosh, C.

AU - Kulkarni, Suresh D.

PY - 2019/5/15

Y1 - 2019/5/15

N2 - 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 40–60 min at 220 °C solution temperature. The as-prepared 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 as-prepared 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 Cr3+ 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.

AB - 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 40–60 min at 220 °C solution temperature. The as-prepared 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 as-prepared 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 Cr3+ 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.

UR - http://www.scopus.com/inward/record.url?scp=85060557400&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85060557400&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2019.01.254

DO - 10.1016/j.jallcom.2019.01.254

M3 - Article

AN - SCOPUS:85060557400

VL - 785

SP - 747

EP - 753

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

ER -