Biomass-Derived Polysilsesquioxane Nanofilament Reinforced Porous Aerogel for Durable Passive Radiative Cooling across All Day and Weather Conditions

Passive radiative cooling (PRC) is a potentially sustainable strategy by reflecting sunlight (0.3–2.5 μm) and emitting heat through the atmospheric window (8–13 μm) without energy consumption. However, challenges remain due to high sunlight irradiance (1000 W m–2) during the day. Our research addresses these challenges by incorporating one-dimensional polysilsesquioxane nanofilaments (1D PSNFs) into micro- and nanoporous biomass-derived aerogels, forming a three-dimensional framework. The designed sustainable aerogel cooler achieves greater than 97% sunlight reflection and thermal emission, resulting in a cooling power of 138.6 W m–2 over 720 h, reducing ambient temperatures by 9 °C. In addition, the aerogel cooler demonstrates high thermal stability, low thermal conductivity (29.0 mW m–1 K–1), superhydrophobicity (water contact angle ∼175°), low density (44.43 kg/m3), and a large surface area (137.84 m2/g). These features enable effective radiative cooling across various weather conditions, while also maintaining environmental sustainability.