Arabic-dome-inspired hierarchical design for stable and high-efficiency solar-driven seawater desalination

Abstract

Interfacial solar steam generation (ISSG) has shown extraordinary promise in achieving high-efficiency seawater desalination. However, a high evaporation rate cannot be maintained because of the seemingly unavoidable heat losses caused by the excessive water in solar absorber. Herein, inspired by the Arabic dome-architectural style, we report an integrated solar evaporator developed through foaming straw-based photothermal polyurethane sponge (SPPU) in the cavity of natural corn straw (NCS). This hierarchical design traps water at the interface between SPPU and NCS during ISSG, which balances water supply and evaporation and prevents harvested solar energy from heating superfluous unevaporated water. Moreover, SSPU with Arabic-dome-style structure ensures excellent photothermal conversion at different light incident angles. The so-fabricated evaporator displays an outstanding evaporation rate (2.18 kg/m2/h) under 1 sun illumination and the small-scale prototype produces a positive freshwater yield (3.58 kg/m2/day) under natural sunlight. This work provides an ingenious route to construct 3D solar evaporator with good water regulation for seawater purification.