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Vol. 8 (2021)

Black Cool Pigments for Urban Heat Island (UHI) Control: from Cr-Hematite to Mn-Melilite

September 26, 2021


Black cool pigments are very interesting for its application in asphalt urban pavements and building floors for moderate the urban heat island effect (UHI) and improving air conditioning energy efficiency. Cool black pigments based on Cr doped hematite Fe2O3 (trigonal, R-3c), hexagonal perovskites YMnO3 (hexagonal, P63cm) and Sr4CuMn2O9 (trigonal, P321) and melilite Sr2(Mg0.5Mn0.5)Ge2O7 (tetragonal, P-421m) with high NIR reflectance synthesized by ceramic and coprecipitation method, are analyzed and compared from color yield in alkyd paint, ceramic glazes and porcelain stoneware, NIR reflectance, bandgap and photocatalytic activity on Orange II substrate. Sr4CuMn2O9 black powders show the nearest hue h to the reference carbon black and the highest NIR reflectance (51%). All pigments show high NIR reflectance in all tested applications. The Fe1.2Cr0.8O3 pigment shows good behavior in the free ZnO glaze and also in porcelain stoneware, YMnO3 and Sr4CuMn2Opigments are compatible with low temperature glazes, but Sr2(Mg0.5Mn0.5)Ge2O7 pigment loses the black color even in low temperature glazes. Sr4CuMn2O9 pigment shows moderate photoactivity on Orange II (t1/2=216 min) and the Fe1.2Cr0.8O3 pigment also shows some activity (t1/2=329 min).


  1. Monrós G, Scheelite and Zircon: Brightness, Color and NIR Reflectance in Ceramics, Nova Scienc Publishers, New York; 2021, ISBN: 978-1-53619-332-9
  2. Akbari H, Levinson R. Evolution of Cool-Roof Standards in the US, Advances in Building Energy Research, 2008; 2: 1-32.
  3. Taha H, Akbari H, Rosenfeld A, Huang J, Residential cooling loads and the urban heat island - the effects of albedo, Building and Environment, 1988; 23,4 : 271-283.
  4. Givoni B. Climate considerations in building and urban design. Van Nostrand Reinhold, New York; 1998.
  5. CPMA Classification and chemical description of the complex inorganic color pigments, fourth ed. Alexandria, Dry Color Manufaturers Association, 2010.
  6. Monrós G, Pigment Ceramic. in Encyclopedia of Color Science and Technology, Ronnier Luo ed., Springer; 2014. ISBN 978-1-4419-8070-0. ON LINE ISBN 978-3-642-27851-8
  7. Llusar M, Bermejo T, Primo JE, Gargori C, Esteve V, Monrós G. Karrooite green pigments doped with Co and Zn: Synthesis, color properties and stability in ceramic glazes. Ceramics International, 2017; 12,43: 9133-9144.
  8. ASTM C1371. Standard Test Method for Determination of Emittance of Materials Near Room Temperature Using Portable Emisometers, (2004).
  9. Cerro S, Gargori C, Llusar M, Monrós G. Orthorhombic (Fe2TiO5)-monoclinic (Cr2TiO5) solid solution series: synthesis by gel routes, coloring and NIR reflectivity evaluation, Ceramics International, 2018; 44(11): 13349-13359.
  10. Gargori C, Cerro S, Fas N, Llusar M, Monrós G. Red-brown ceramic pigments based on chromium doped ferrian armalcolite, effect of mineralizers, Ceramics International, 2017; 43: 5490-5497.
  11. Gargori C, Cerro S, Fas N, Llusar M, Monrós G. Study of the photocatalytic activity and cool characteristics of a novel palette of pigments, Boletín Sociedad Española Cerámica Vidrio, 2017; 56: 166-176.
  12. Munsell AH. Atlas of the Munsell color system, Malden, Mass., Wadsworth, Howland & Co., inc. , Printers, 1915.
  13. Molinari C, Conte S, Zanelli C, Ardit M, Cruciani G, Dondi M. Ceramic Pigments and Dyes beyond the Inkjet Revolution; from Technological Requirements to Constraints in Colorant Design, Ceramics International, 2020; 46(14): 21839-21872.
  14. Monrós G. Sol-Gel Materials for Pigments and Ceramics, The Sol-Gel Handbook - Synthesis, Characterization and Applications Vol. 3, ed. David Levy and Marcos Zayat, Wiley; 2015, ISBN 9783527334865.
  15. Boudjemaa A. Photo-catalytic hydrogen production over Fe2O3 based catalysts, International, Journal of Hydrogen Energy, 2010; 35,15: 7684-7689
  16. Eppler RA. Cobalt-free black pigments, American Ceramic Society Bulletin, 1981; 61: 562-565.
  17. Ozel M, Turan S. Production and Characterization of Iron-Chromium Pigments and Their Interactions with Transparent Glazes, Journal of the European Ceramic Society, 2003; 23(12): 2097-2104
  18. Escardino A, Mestre S, Barba A, Beltrán V, Blasco A. Synthesis mechanism of an iron-chromium ceramic pigment, Journal of the American Ceramic Society, 2000; 83: 29-32.
  19. De Teresa JM, Ibarra MR, Algarabel PA, Ritter C. Evidence for magnetic polarons in the magnetoresistive perovskites, Nature, 1997; 386: 256-259.
  20. Smith AE, Mizoguchi H, Delaney K, Spaldin NA, Sleight AW, Subramanian MA. "Mn3+ in trigonal bipyramidal coordination: a new blue chromophore", J Am Chem Soc, 2009; 131: 17084-6.
  21. Li J, Sleight AW, Subramanian MA. Determination of the Local Environment of Mn3+ and In3+ in the YInO3−YMnO3 Solid Solution, Which Exhibits an Intense Blue Color, Chem Mater, 2016; 28: 6050-6053.
  22. Abed AE, Gaudin E, Darriet J. Tetrastrontium dimanganese copper nonaoxide, Sr4CuMn2O9. Acta Cryst, 2002; C58: i138-i140.
  23. Abed El, Gaudin E, Darriet J, Whangbo MH. Magnetic Susceptibility and Spin Exchange Interactions of the Hexagonal Perovskite-Type Oxides Sr4/3(Mn2/3Ni1/3)O3, Journal of Solid State Chemistry, 2002; 163: 513-518.
  24. Byungseo B, Naoki T, Shinji T, Nobuhito I. Environmentally friendly orange pigments based on hexagonal perovskitetype compounds and their high NIR reflectivity, Dyes and Pigments, 2017; 147: 523-528.
  25. Endo T, Doi Y, Hinatsu Y, Ohoyama K. Magnetic and Neutron Diffraction Study on Melilite-Type Oxides Sr2MGe2O7 (M = Mn, Co), Inorg Chem, 2012; 51: 3572-3578.
  26. Kim TG, Kim SJ, Lin CC, Liu RS, Chand TS, Ima SJ. Melilitetype blue chromophores based on Mn3+ in a trigonalbipyramidal coordination induced by interstitial oxygen, J Mater Chem, 2013; C,1: 5843-5848.
  27. CIE Comission International de l'Eclairage, Recommendations on Uniform Color Spaces, Colour Difference Equations, Psychometrics Colour Terms. Suplement nº2 of CIE Pub. Nº15 (E1-1.31) 1971, Bureau Central de la CIE, Paris (1978).
  28. Tauc J, Grigorovici R, Vancu A. Optical Properties and Electronic Structure of Amorphous Germanium, Phys Status Solidi, 1966; 15,2: 627-637.
  29. Kubelka P, and Munk F. Ein Beitrag Zur Optik Der Farbanstriche. Z. Techn. Phys., 1931; 12: 593 -601.
  30. Goldstein J. Scanning Electron Microscopy and X-Ray Microanalysis. Springer, 2003, ISBN 978-0-306-47292-3.
  31. Konstantyinou IK, Albanis TA. TiO2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations. A review, Applied Catalyst B: Environmental, 2004; 49: 1-14.
  32. Munsell AH, Color Notation G.H Elis Company, 1905.
  33. Schabbacha LM, Marinoski DL, Güthsb S, Bernardinc AM, Fredel MC. Pigmented glazed ceramic roof tiles in Brazil: Thermal and optical properties related to solar reflectance index, Solar Energy, 2018; 159: 113-124.
  34. Cruciani G, Dondi M, Ardit A, Lyubenova TS, Carda JB, Matteucci F, Costa AL. Malayaite ceramic pigments: A combined optical spectroscopy and neutron/X-ray diffraction study, Materials Research Bulletin, 2009; 44: 1778-1785.
  35. Vicent JB, Llusar M, Badenes J, Tena MA, Vicente M, Monrós G. Occlusion of chromophore oxides by Sol-Gel methods: Application to the synthesis of hematite-silica red pigments, Boletín Sociedad Española Cerámica Vidrio, 2000; 39,1: 83-93.
  36. Tanabe Y, Sugano S. On the absorption spectra of complex ions III, Journal of the Physical Society of Japan, 1956; 11: 864-877.
  37. Pozza G, Ajò D, Chiari G, De Zuane F, Favaro M. Photoluminescence of the inorganic pigments Egyptian blue, Han blue and Han purple. J Cult Heritage, 2000; 1: 393-398.
  38. Kendrick E, Kirk CJ, Dann SE. Structure and colour properties in the Egyptian Blue Family, M1-xM'xCuSi4O10, as a function of M, M' where M, M'=Ca, Sr and Ba. Dyes Pigm, 2007: 73: 13-18.
  39. Shannon RD. Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides, Acta Cryst, 1976; A32: 751.
  40. Czaja M, Lisiecki R, Chrobak A, Sitko R, Mazurak Z. The absorption- and luminescence spectra of Mn3+ in beryl and vesuvianite, Physics and Chemistry of Minerals, 2018; 45: 475-488.
  41. Weyl WA. Coloured Glasses, Dawson's of Pall Mall, London, 1959. https: //
  42. Ohtani B, Prieto-Mahaney OO, Lirabe D. What is Degussa (Evonik) P25? Crystalline composition analysis, reconstruction from isolated pure particles and photocatalytic activity test, Journal of Photochemistry and Photobiology A: Chemistry, 2010; 216(2-3): 179-182
  43. Shockley W. Electrons and holes in semiconductors, D. Van Nostrand Company, 1959.