Commercial‐Like Self‐Cleaning Colored ZrO2‐Based Bilayer Coating for Remarkable Daytime Sub‐Ambient Radiative Cooling

Abstract

AbstractPassive daytime radiative cooling (PDRC) is a low‐carbon energy technology to early achieve the “carbon neutrality” goal. Developing the commercial‐like colored PDRC coatings with sub‐ambient cooling performance is still a big challenge. Herein, a colored bilayer ZrO2‐PVDF PDRC coating with sub‐ambient cooling performance, self‐cleaning, and good weather resistance property is first reported. The colored bilayer coating is composed of a thick ultra‐white ZrO2‐PVDF reflective layer (Rsolar = 0.984) and a thin colorful layer. The obtained red bilayer ZrO2‐PVDF PDRC coating has a high solar reflectance (Rsolar = 0.950), which could realize the maximum temperature drop of 3.0 °C, and the calculated theoretical cooling power is as high as 131.66 W m−2, showing a good sub‐ambient cooling performance. Furthermore, they show a good self‐cleaning property. Meanwhile, the accelerated aging tests prove that they have a good weather resistance. This work provides a low‐cost, simple, and large‐scale method to prepare the commercial‐like colored PDRC coatings with the sub‐ambient cooling performance, showing a great practical application value.