TY - JOUR AU - G. Monrós, AU - S. Cerro, AU - J.A. Badenes, AU - M. Llusar, PY - 2021/07/01 Y2 - 2024/03/29 TI - Black Cool Pigments for Urban Heat Island (UHI) Control: from Cr-Hematite to Mn-Melilite JF - Journal of Solar Energy Research Updates JA - J. Solar Eneg. Res. Updat. VL - 8 IS - SE - Articles DO - 10.31875/2410-2199.2021.08.4 UR - https://www.zealpress.com/jms/index.php/jseru/article/view/313 SP - 27-44 AB - <p>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 Fe<sub>2</sub>O<sub>3</sub>&nbsp;(trigonal,&nbsp;<em>R-3c</em>), hexagonal perovskites YMnO<sub>3</sub>&nbsp;(hexagonal,&nbsp;<em>P6<sub>3</sub>cm</em>) and Sr<sub>4</sub>CuMn<sub>2</sub>O<sub>9</sub>&nbsp;(trigonal,&nbsp;<em>P321</em>) and melilite Sr<sub>2</sub>(Mg<sub>0.5</sub>Mn<sub>0.5</sub>)Ge<sub>2</sub>O<sub>7</sub>&nbsp;(tetragonal,&nbsp;<em>P-42<sub>1</sub>m</em>) 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. Sr<sub>4</sub>CuMn<sub>2</sub>O<sub>9</sub>&nbsp;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 Fe<sub>1.2</sub>Cr<sub>0.8</sub>O<sub>3</sub>&nbsp;pigment shows good behavior in the free ZnO glaze and also in porcelain stoneware, YMnO<sub>3</sub>&nbsp;and Sr<sub>4</sub>CuMn<sub>2</sub>O<sub>9&nbsp;</sub>pigments are compatible with low temperature glazes, but Sr<sub>2</sub>(Mg<sub>0.5</sub>Mn<sub>0.5</sub>)Ge<sub>2</sub>O<sub>7</sub>&nbsp;pigment loses the black color even in low temperature glazes. Sr<sub>4</sub>CuMn<sub>2</sub>O<sub>9</sub>&nbsp;pigment shows moderate photoactivity on Orange II (t<sub>1/2</sub>=216 min) and the Fe1.2Cr0.8O3 pigment also shows some activity (t<sub>1/2</sub>=329 min).</p> ER -