Benincasa hispidas-inspired pore-gradient aerogel with integrated water and thermal management for highly efficient solar vapor generation and water purification

Abstract

Engineering the pore structure of evaporator to effectively integrate water and thermal management is critical for efficient solar-driven interfacial vapor generation. Here, inspired by the unique structure of Benincasa hispidas, a bioinspired pore-gradient aerogel was fabricated for the first time. Experiments and numerical simulations reveal that the unique anisotropic porous structure of aerogel, which consists of small-pores at top region and large-pores at bottom region, enabling it to maximize the heat gains from the sunlight and localize the generated heat while provide adequate water supply concurrently. Under solar illumination (1 kW m−2), the fabricated aerogel can achieve a high evaporation rate of 2.49 kg m−2h−1, and the calculated energy efficiency is approximately 96.3 %, which is comparable to most of state-of-the-art evaporators. Additionally, with this aerogel employed, effective purification toward various undrinkable water can be achieved. This work derives from nature, providing us a design blueprint to integrate water and thermal management in a bulky material, and it is expected to advance one step further toward the design and practical application of high-performance solar evaporators.