A superhydrophobic wood aerogel for radiative cooling and sound absorption†

Abstract

Passive daytime radiative cooling, as an environmentally friendly and sustainable cooling approach, can effectuate efficient temperature reduction without energy input. Nevertheless, the majority of radiative cooling materials were obtained by making use of unsustainable materials and have limited functionality. To overcome these limitations, we fabricated a radiative cooling wood aerogel (WA) with sound absorption ability. The as-fabricated WA reflects 92% of solar light and remits 98% of infrared, achieving an average temperature reduction of 10 °C under direct sunlight. Importantly, the WA possesses a high sound absorption coefficient of 0.4 within the frequency range of 500–3000 Hz owing to its high porosity of 95%. Superhydrophobization of the WA empowers the aerogel to be stable against outdoor rain rinsing and weathering. This work provides a new strategy for multifunctional radiative cooling materials for diverse applications using naturally available resources.