A mechanically durable, sustained corrosion-resistant photothermal nanofiber membrane for highly efficient solar distillation

So far, solar distillation based on photothermal membranes has attracted ever-increasing attention in less developed regions for water purification. The raw water resources for solar evaporation were generally beyond the natural hydrological cycle and are highly saline and corrosive. In this process, a core-shell structured PDA/PEI/PPy@PI nanofibrous membrane (NFM), comprising a robust PI nanofibrous substrate, PPy photothermal layer and anticorrosion PDA/PEI layer, was developed as a photothermal membrane, which exhibited broadband solar absorption (93.0%) and sustained anti-corrosion capacity for 30 days. Besides, the core-shell structure can effectively prevent the swelling of the membrane and maintain excellent mechanical strength even in the wet state. An evaporation system based on the PDA/PEI/PPy@PI NFM achieved a high solar evaporation rate of ≈1.43 kg m^-2 h^-1, corresponding to a light-to-vapor efficiency of ≈86.9% under 1 sun illumination. Due to its sustained corrosion-resistance, mechanical durability in the wet state and high solar evaporation capacity, this NFM is expected to have great potential for long-term solar distillation applications.