Interfacial solar evaporator synergistic phase change energy storage for all-day steam generation

Abstract

Solar-driven interface water evaporation has been demonstrated to be one of the most promising technologies for alleviating global water pollution and water shortage. Although significant advances have been achieved for improving the solar-to-vapor efficiency, the design and fabrication of an all-day solar steam generator with highly efficient evaporation performance still remains a challenge due to the day/night cycle. Herein, we report a novel solar-driven interfacial evaporator composed of a polypyrrole impregnated nylon thread as the photothermal layer and octadecane/carbonized polypyrrole nanotube aerogel composite materials as the photothermal energy storage device to achieve highly efficient all-day solar steam generation. By the combination of photothermal conversion and photothermal energy storage, the as-prepared solar steam evaporator achieves a high evaporation rate of 2.62 kg m⁻² h⁻¹ and excellent solar-to-vapor efficiency of 92.7% under 1 kW m⁻² illumination. Moreover, the evaporator exhibits excellent salt resistance and there was no obvious salt precipitation observed with 6 h continuous evaporation in 3.5% NaCl aqueous solution. Besides, in the outdoor experiment, the evaporator shows high water production of 8.42 L m⁻² in the daytime and 1.22 L m⁻² in the nighttime. The findings of this work may provide a novel strategy for the fabrication of the all-day solar-driven interface water evaporation device to mitigate freshwater scarcity, and meanwhile this work lays the foundation for breaking the restriction of the day/night cycle during the solar steam generation process.