摘要
Solar-driven desalination has been considered as a promising technology for producing clean water through an abundant and pollution-free energy source.It is a critical challenge to reasonably design the porous morphology and the thermal management of photothermal membranes for enabling efficient energy conversion and water production.In this work,a Janus poly(vinylidene fluoride)membrane was fabricated in combination of penetrative pore structure,asymmetric surface wettability with proper thermal management for high-efficiency solar desalination.Highly open and directly penetrative pores achieved by the two-dimensional solvent freezing strategy are considered to provide direct pathways for water and vapor transportation.The unique feature of hydrophobic upper layer/hydrophilic lower layer enables the photothermal membranes to self-float on the water surface and rapidly pump water from the bulk to the surface.The resulting Janus membrane exhibits a satisfactory light absorbance as high as 97%and a photothermal conversion efficiency of 62.8%under one-sun irradiation in a direct contact mode.The solar-to-vapor efficiency rises up to 90.2%with the assistance of a thermal insulator adopted beneath.Both the Janus membrane and the composite setup are able to work efficiently with a high stability in seawater desalination,and the concentration of ion in condensed water is reduced to below 1 ppm.Therefore,Janus membranes with directly penetrative pores and photothermal surfaces shine a light on the development of high-performance solar evaporators for the practical application in solar seawater desalination.
基金
This work was supported by the National Natural Science Foundation of China(Grant no.51673166 and no.51803180).
