Hollow-Porous Carbon Nanofibers Loaded with CuS Nanoparticles for Efficient Solar-Driven Interfacial Evaporation

Facing escalating water scarcity, solar-driven interfacial evaporation (SDIE) has emerged as a sustainable desalination paradigm. However, practical deployment is hindered by the trade-off between thermal localization, water transport, and salt resistance in conventional materials. Herein, we report a hollow-porous carbon nanofiber membrane loaded with CuS nanoparticles (CuS@HPCNFs) fabricated via coaxial electrospinning. The through-porous architecture reduces thermal conductivity, while the plasmonic CuS nanoparticles enable broadband absorption, achieving a surface temperature of 92.8 °C under 1 sun illumination. Consequently, CuS@HPCNFs delivers an evaporation rate of 2.39 kg·m^–2·h^–1 with a solar-to-vapor efficiency of 83.5%, calculated via energy balance accounting for conduction, convection, and radiation losses. The hydrated CuS surface disrupts the hydrogen-bond network of interfacial water, reducing the evaporation enthalpy to 1816 J·g^–1. The material exhibits stable performance in 15 wt % NaCl brine for 10 h and significantly reduces metal ion concentrations in seawater under outdoor conditions. This work provides a structural-functional coupling paradigm for developing scalable SDIE materials.