A novel carbonated inorganic radiative cooling material and its spectral manipulation mechanism

The global temperature rising and building cooling energy consumption increasing have caused a serious concern. This study proposed a novel carbonated inorganic radiative cooling material, called as γ-dicalcium silicate carbonated radiative cooling coatings (CRCC), expected to be used for building cooling through spectral emission from buildings to space. In terms of CRCC, high reflectivity to the solar spectrum and high emissivity to the atmospheric window (8–13 μm wavelength) can be achieved by simply optimizing the preparation solid/water ratio. This is attributed to the reaction products actions between CO 2 and γ-dicalcium silicate. The predominantly consisting of CaCO 3 , the vibrational characteristics of C O and Si O bonds, and along with a surface porous structure offer the excellent and distinctive spectrum and scattering characteristics. The addition of nano Al 2 O 3 could further enhance the spectral performance of CRCC, which present an exceeding 95 % reflectivity to solar spectrum, and over 97 % emissivity to the atmospheric window, resulting in a cooling effect of ca 7 °C for the modified CRCC surface. The numerical calculation and finite element analysis further validated the superior radiative cooling performance of CRCC, demonstrating their capability to maintain lower temperatures. We believe that the CRCC not only serves as a low-carbon construction material but also facilitates radiative cooling, contributing to energy savings in buildings, and achieving low-carbon environmental protection.