Bio-based radiative cooling materials offer a promising pathway toward sustainable and carbon-free thermal management. However, their practical application is often constrained by limited cooling efficiency, inherent hydrophilicity, and flammability. Inspired by the photonic architecture of Pieris rapae butterfly wings, a biomimetic wood cement aerogel featuring a "pane-nanobeads" structure was developed. This was achieved through in-situ anchoring of cement-based nanoparticles followed by fluorination modification. Benefiting from its unique bioinspired design, the resulting aerogel exhibited a high solar reflectance of 91.3% and an infrared emissivity of 99.1%, enabling a cooling temperature of 11.6 °C and a net cooling power of 84.8 W/m² under solar irradiance of 800 W/m². In hot regions of China, this performance translates to annual cooling energy savings of approximately 43.6 MJ/m². Furthermore, the material demonstrated exceptional superhydrophobicity, flame resistance, and remarkable environmental durability. Even after severe accelerated weathering involving extreme thermal cycling and intense UV irradiation, the aerogel maintained its structural integrity, superhydrophobicity, and a robust cooling drop of 9.4 °C. This work presents a scalable and effective strategy for designing high-performance, fire-safe radiative cooling materials, advancing the development of eco-friendly passive cooling technologies.

Bio-based radiative cooling materials hold significant application potential in carbon-free passive cooling but suffer from performance loss due to dust accumulation and rainwater washing. Superhydrophobic surfaces can enhance self-cleaning and durability, yet poor abrasion resistance often compromises superhydrophobicity. Herein, we develop a wood-based nanocomposite by infiltrating a highly porous and low-surface-energy copolymer and SiO₂ nanoparticles into a delignified wood scaffold. The resulting nanocomposite achieved satisfactory radiative cooling performance, with a solar reflectance of 91.29% and infrared emissivity of 98.77%, yielding a sub-ambient cooling of 8.36 °C and potential energy savings of 32.27 MJ/m² in cooling energy consumption in China’s hottest regions. Furthermore, even after rigorous environmental testing, including 3000 abrasion cycles, water washing, and solvent immersion, the nanocomposite still maintained exceptional superhydrophobicity (contact angle > 160°, rolling angle < 4°). More importantly, the wood-based nanocomposite retained approximately 80% of its cooling capability after rigorous environmental testing. This work provides practical solutions to the two questions of inadequate abrasion resistance in bio-based superhydrophobic materials and poor long-term performance of bio-based radiative cooling materials, which is of great significance and value for the high-value application of bio-based functional materials.