Single Nanoporous MgHPO4·1.2H2O for Daytime Radiative Cooling

• Published in: ACS applied materials & interfaces Vol. 12; no. 2; pp. 2252 - 2258
• Main Authors: Huang, Xia, Li, Na, Wang, Junfeng, Liu, Defang, Xu, Jing, Zhang, Zhijie, Zhong, Mingfeng
• Format: Journal Article
• Language: English
• Published: American Chemical Society 15.01.2020
• Subjects: single; daytime radiative cooling; high reflectivity; high emissivity; MgHPO4·1.2H2O powder
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.9b14615

Objects can radiate emission of heat to outer empty space (3 K) through an atmospheric window (8–13 μm), resulting in a possibility for radiative cooling. Multilayer film stacking designs and complex nanophoton coolers have been reported for radiative cooling. Here, we have found that single nanoporous MgHPO4·1.2H2O powder has a high reflectance of 92.20% in the solar spectral region of 0.3–2.5 μm and a high emissivity of 0.94 in the atmospheric window of 8–13 μm. The powder was film-coated on ceramic tiles for temperature and cooling power tests on Al foil. The test results showed that the MgHPO4·1.2H2O coating on the ceramic tile could achieves a daytime radiative cooling of 4.1 °C below the ambient air temperature and a nighttime radiative cooling of 7.6 °C. The average cooling power reaches 78.18 W/m2. Such a simple and low-cost single nanoporous MgHPO4·1.2H2O powder material offers a novel option for large-scale applications of radiative cooling.