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

Passive 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 (R-solar = 0.984) and a thin colorful layer. The obtained red bilayer ZrO2-PVDF PDRC coating has a high solar reflectance (R-solar = 0.950), which could realize the maximum temperature drop of 3.0 degrees 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.