Low-Cost, Eco-Friendly, and High-Performance 3D Laser-Induced Graphene Evaporator for Continuous Solar-Powered Water Desalination.

Abstract

Water scarcity has become a global challenge attributed to climate change, deforestation, population growth, and increasing water demand. While advanced water production plants are prevalent in urban areas, remote islands and sparsely populated regions face significant obstacles in establishing such technologies. Consequently, there is an urgent need for efficient, affordable, and sustainable water production technologies in these areas. Herein, we present a facile approach utilizing an ultrashort-pulsed laser to directly convert cotton fabric into graphene under ambient conditions. The resulting laser-induced graphene (LIG) demonstrates the highest light absorption efficiency of 99.0% and a broad absorption range (250-2500 nm). As an excellent solar absorber, LIG on cotton fabric can efficiently absorb 98.6% of the total solar irradiance and its surface temperature can reach 84.5 °C under sunlight without optical concentration. Moreover, we propose a cost-effective 3D LIG evaporator (LIGE) for continuous solar-powered desalination. This innovative design effectively mitigates salt formation issues and enhances the steam generation efficiency. The water evaporation rate and the solar-to-vapor conversion efficiency are measured to be around 1.709 kg m^-2 h^-1 and 95.1%, respectively, which surpass those reported in previous studies. The simplicity, durability, and continuous operational capability of the 3D LIGE offer promising prospects to address the growing challenges in global water scarcity.