Lanthanide doped two dimensional heterostructure nanosheets with highly efficient harvest towards solar energy

At present, the shortage of potable water is still a critical issue. The emerging of solar-driven evaporation technique offers a promising way to solve freshwater scarcity. However, developing highly efficient evaporation system is still a challenge. Herein, this work developed two-dimensional heterostructure nanosheets as the photothermal agent. We used the WSe2 nanosheets to enhance the absorption of graphene and facilitate the heat localization due to its higher visible light absorption and ultralow thermal conductivity. And graphene provided the low surface reflection and a broad absorption spectrum. Moreover, the enhanced near infrared photothermal conversion of the heterostructure nanosheets is realized to be 41.4% higher than some previous works by introducing lanthanide ions. A series of experiments are performed to determine its heterostructure. Besides, the interfacial evaporation system has been constructed based on as-prepared nanosheets, exhibiting excellent solar-to-heat efficiency of 91.8% and water evaporation rate of 1.672 kg m−2h−1 under stimulated 1 sun irradiation. It is suggested that developed nanosheets have the potential application for highly effective solar-driven evaporation.