A biomass hybrid hydrogel with hierarchical porous structure for efficient solar steam generation

Solar steam generation is a promising method for clean water production. However, existing evaporation systems are limited by either expensive and complex equipment, or inadequate solar evaporation performance. In this paper, we prepared a biomass hybrid hydrogel (BHH) with hierarchical porous structure for efficient solar evaporation, in which starch and chitosan were used as hydrophilic substrates and PDA-Fe NPs was used as absorber. This specific microstructure plays an important role in improving light absorption, photothermal conversion and water transportation. The kerosene lamp structure evaporator endows centralized heat management and less heat loss. Therefore, our BHH evaporator performs high evaporation rate (3.9 kg m-2 h-1) and solar evaporation efficiency (103.2%). In addition, the evaporator shows favorable salt-resistant, durability and self-cleaning capacity, ensuring long-term and stable seawater evaporation. This study paves a new way for the development of low-cost, sustainable, efficient and salt-resistant evaporators for solar evaporation and desalination.