Robust PEDOT:PSS-based hydrogel for highly efficient interfacial solar water purification

Solar water purification has been attracting considerable attention due to its promising desalination and purification applications to alleviate water scarcity and pollution. However, despite recent rapid progress, rational design and development of robust and highly efficient interfacial photothermal materials sufficing for large scale real usage is still a critical challenge to the science and technology of this field. Herein, we develop a mechanically robust nanocomposite hydrogel with intriguing evaporation performance by simple blending and cross-linking of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) nanofibrils and poly(vinyl alcohol) (PVA) viscous solution. As-prepared PEDOT:PSS-PVA hydrogel exhibits an excellent light absorption ratio of ∼ 99.7% in a wide wavelength range of 250 ∼ 2500 nm and displays unprecedented high energy efficiency of ∼ 98.0% with a fast evaporation rate of ∼ 2.84 kg m-2 h-1 under one sun irradiation. A 60-day continuous test simulating the real seawater evaporation environment shows superior long-term stability of such hydrogel with an average energy efficiency of ∼ 93.3%. To harness these advantageous properties, we further demonstrate the scalable hydrogel production and fabricate a solar water evaporator equipment for seawater desalination and wastewater purification, from which the acquired water can meet the drinking requirements set by the World Health Organization.