Improving evaporation rate is extremely important to promote the application of solar steam generation in clean water production through seawater desalination. However, the theoretical evaporation rate limit of a normal two-dimensional (2D) photothermal evaporator is only about 1.46 kg m-2 h-1. While 3D evaporators can break the limit, they require much more raw materials. In this work, an effective approach for achieving high-yield solar steam generation via the synergy of 2D nanostructure-embedded all-in-one hybrid hydrogel evaporator and surface patterning is reported. This improved surface-patterned evaporator is able to simultaneously lower the enthalpy of vaporization and induce the Marangoni effect near the evaporation surface, thus delivering a high evaporation rate of 3.62 kg m-2 h-1, which is more than twice the theoretical limit of the normal 2D photothermal evaporator. This hybrid hydrogel offers a cost-effective and energy-efficient pathway to mitigate clean water shortages.
Keywords: MXene; graphene; hybrid hydrogels; solar steam generation; surface patterning.