A “solar basking cloth” evaporator constructed of Bi2OS2 hydrogel-melamine foam for efficient solar steam generation

Abstract

Solar-driven steam generation (SSG) technology, as a breakthrough solution to the global water crisis, not only establishes a green pathway for clean freshwater access but also pioneers an innovative paradigm for synergistic energy-environment governance. Currently, while significant academic progress has been made, overcoming bottlenecks in evaporation rate and energy conversion efficiency remains crucial for practical implementation. Here, this study constructs a bismuth oxide sulfide hydrogel-melamine foam evaporator (abbreviated as Bi₂OS₂ Gel-MF) featuring a three-dimensional multi-level water transport system via synthesizing novel Bi₂OS₂ nanosheets and drawing inspiration from traditional “solar basking cloth” structures. In this system, the hydrophilic MF framework acts as a “water transport artery” and continuously supplies water to the surface “evaporation fabric” (Bi₂OS₂ hydrogel), enabling rapid water transport and evaporation. Under standard solar irradiance, the Bi₂OS₂ Gel-MF achieves an evaporation rate of 3.30 kg m⁻² h⁻¹, demonstrating long-term sustainability and durability. This structure also exhibits excellent desalination performance and evaporation rates in practical seawater desalination, highlighting its potential applications in solar seawater desalination and photothermal water treatment.