Solar vapor generation, which can separate the soluble or dispersing contaminants from water, is particularly desirable owing to its green energy utilization for water purification technology. Here, we present a concept of enhancing solar vapor generation by tailoring surface topography of the hydrogel-based solar evaporator. Via nanotexture-enhanced heat flux at the evaporation front, the obtained solar evaporator achieves a water evaporation rate of ∼2.6 kg m-2 h-1 at ∼91% energy efficiency under one sun (1 kW m-2). An easy-to-install solar still based on this solar evaporator consisting of cost-effective poly(vinyl alcohol) and activated carbon is deployed to demonstrate the potential for domestic or urgent water purification purposes. Such new design principles of hydrogel-based solar evaporators provides a useful means for surface-enhanced water evaporation to inspire scalable and processable solar evaporators from accessible raw materials.
Keywords: Solar vapor generation; desalination; hydrogel; surface topography; water purification.