Synthesis of hollow copper sulfide nanocubes with low emissivity for highly efficient solar steam generation

Interfacial solar steam generation is an eco-friend and energy-efficient way of harvesting solar energy for desalination and wastewater treatment. For the solar steam generation, the primary focus is to design new materials that are fully sunlight absorption, fast photothermal conversion and low heat emissivity. Here, a novel hollow copper sulfide (CuS) nanocubes with concave surface is used for rapid and efficient solar steam generation through the micro thermal management. Interestingly, the emissivity of CuS foam is as low as 0.64, whose absorption is more than 97% and strongly dependents on the structure and morphology. The unique concave structure of hollow CuS can trap the sunlight by reabsorption as well as recover radiative and convective heat loss. As a result, the CuS based generator exhibits a high evaporation efficiency of 91.5% under one sun illumination. Furthermore, the device can maintain a stable performance of solar steam generation during the cyclic seawater desalination. The novel structure design based on the micro thermal management offers a new insight into the future development of highly efficient solar steam generation.