Integrated light adsorption and thermal insulation of Zn doping 1T phase MoS2-based evaporation prototype for continuous freshwater generation

Abstract

Solar-driven interfacial evaporation is regarded as an emerging technology to produce freshwater from seawater or wastewater to alleviate the global water crisis. The advanced interfacial solar evaporation system with three-dimensional (3D) structure is devised to achieve high photothermal-conversion efficiency. Considering that photothermal materials is decisive to the improvement of the solar evaporation systems, Zn doping 1 T-MoS2 (denoted as Zn-MoS2) is fabricated via a simple one-step hydrothermal method for achieving high solar absorption. Zn-MoS2 modified bio-waste sorghum straw (denoted as ZnMoSSE) is utilized to construct 3D solar evaporators with different structures. ZnMoSSE-based cone shaped evaporation device exhibits a notably high evaporation rate of 3.46 kg m-2h−1 though enlarged evaporation surface under one sun illumination, which exceeds the theoretical limit (1.47 kg m-2h−1). An ultrafast evaporation rate of up to 4.13 kg m-2h−1 is achieved by the introduction of the convection flow. Furthermore, the ZnMoSSE-based cone shaped evaporation device possesses antifouling property with continuously treating high-salinity brine for 10 h, and stable evaporation performance even in 15 wt% NaCl brine. Experiments and COMSOL Multiphysics calculations imply that ZnMoSSE displays superior light harvesting, remarkable thermal insulation, fast water transportation and effective salt-resistant performance. Owing to the home-made water generation device containing sand for thermal insulation, the water productivity of device is 23.23 kg m−2 in the daytime, and an evaporation rate of 1.29 kg m-2h−1 is obtained without solar irradiation. The novel water generation device enables facile scale-up of efficient lasting freshwater production, holding great promise for the practical application.