The building sector faces dual challenges of high cooling energy consumption and significant fire risks from conventional construction materials. To tackle these challenges, the present research devises an innovative wood-derived composite that simultaneously provides exceptional passive daytime radiative cooling and enhanced fire safety. The material is fabricated via a two-stage fabrication procedure: delignifying natural wood so as to construct a porous framework with inherent light-scattering properties, followed by infiltrating it with a functional mixture of polyvinyl alcohol (PVA), ammonium polyphosphate (APP), and silica (SiO₂) microspheres thereby forming a structurally integrated aerogel-mimicking structure within the wood's microchannels. The final composite demonstrates outstanding optical characteristics, achieving 89% solar reflectance and 97% thermal emissivity within the atmospheric transmission window (spanning 8–13 μm). These properties enable sub-ambient cooling, achieving a maximum 15.6 °C temperature reduction relative to pristine natural wood under direct solar irradiation. In terms of fire safety, the composite attains a UL-94 V-0 classification, demonstrating self-quenching properties and significantly reduced heat release rate during combustion. This multifunctionality arises from synergistic component contributions: the delignified wood provides a reflective and insulating base, SiO₂ microspheres enhance solar scattering, and the PVA-based matrix improves mid-infrared emission. The APP/PVA system acts as the primary flame-retardant by promoting char formation, while SiO₂ particles provide supplementary barrier effects. This research proposes a feasible and eco-friendly strategy for engineering high-performance construction materials that reduce cooling energy demands while improving fire safety, offering a promising pathway toward energy-efficient and safer built environments. • A novel wood-based composite integrates passive daytime radiative cooling (89% solar reflectance, 97% emissivity) and UL-94 V-0 flame retardancy. • Achieves a maximum 15.6 °C sub-ambient cooling under direct sunlight, outperforming natural wood significantly. • Delignified wood scaffold + PVA/APP/SiO₂ aerogel enables synergistic light scattering, heat emission, and char formation. • Building energy simulations confirm ~7–9% cooling energy savings, especially effective in hot, sunny climates. • Sustainable fabrication strategy offers a practical pathway for energy-efficient, fire-safe building materials.
Guo et al. (2026) studied this question.