Zeolitic Imidazolate Framework ‐8‐Based Passive Daytime Radiative Cooling Paint for Energy‐Efficient Cooling

Abstract

Increased energy consumption, driven by climate change and the rise of new industries, has spurred a demand for alternative cooling technologies to replace energy‐intensive systems and mitigate environmental pollution. Radiative cooling, leveraging the optical properties of materials to cool without emitting pollutants or consuming energy, is considered a suitable solution. Among the various form of radiative cooling devices, paint stands out as a practical application for radiative cooling. Hence, a passive daytime radiative cooling (PDRC) paint is developed using a polyurethane binder and zeolitic imidazolate framework (ZIF)‐8. ZIF‐8 is synthesized in an environmentally friendly manner using deionized water as the solvent, resulting in paint with a reflectance of 94.9%, emissivity of 94%, and cooling power of 113 W m−2. Temperature measurements reveal that the paint reduced ambient temperatures by an average of 5.7 °C, reaching up to 8.1 °C during the day. Additionally, with a self‐assembly monolayer coating, the PDRC surface exhibited super‐hydrophobicity and self‐cleaning capabilities. Therefore, the proposed ZIF‐8‐based PDRC paint offers sub‐room temperature cooling potential and is anticipated to reduce energy consumption for cooling, thereby alleviating environmental pollution in various applications, particularly in building exteriors.

Keywords

• metal–organic framework
• paint
• radiative cooling
• super‐hydrophobic surface
• ZIF‐8