Optimized Preparation of CuS@SiO2 Core-Shell Nanoparticles with Strong LSPR Absorption and Excellent Photostability for Highly Efficient Solar-driven Interfacial Water Evaporation

Covellite copper sulfide nanocrystals(CuS NCs) are typical p-type semiconductors, showing strong optical absorption in the near-infrared(NIR) region thanks to their notable localized surface plasmon resonance(LSPR) properties. However, their LSPR properties and compositions are both highly susceptible to the external environment, which severely limits their practical applications. Until now, it remains a technical challenge to improve the structural and optical stability without sacrificing the LSPR performance of CuS NCs. Herein, to solve such a challenge, CuS@SiO 2 NPs with various silica shell thicknesses(CSNs- X nm) were synthesized in a well-controlled fashion via optimizing reverse microemulsion coating protocol. Compared with the pristine CuS NCs, the as-prepared CuS@SiO 2 NPs exhibited comparable LSPR properties but much higher photostability, enabling resistance to various harsh environments( e.g. , high-power irradiation, strong reduction, and oxidation environment). Impressively, when used in solar-driven interfacial water evaporation, all the CuS@SiO 2 NPs exhibited excellent water evaporation performance with efficiencies beyond 70%(as high as 75.2% for CSN-23 nm) after 20 continuous testing cycles. Evidently, this paper is greatly helpful in better designing and fabricating high-performance plasmonic materials for practical photoelectrical, photothermal, and photocatalytic applications.