Thin Polymeric Nanoparticle Membrane Coupled With Photothermal Membrane for Unprecedented Solar‐Driven VOCs Removal

Abstract The removal of trace volatile organic compounds (VOCs) from water through solar‐driven evaporation is crucial for ensuring access to safe drinking water. However, the faster evaporation rate of VOCs compared to water presents a significant challenge in effectively removing these hazardous compounds. To address this issue, a thin polymeric nanoparticle separation membrane is integrated with a photothermal membrane, forming a dual‐layer solar evaporator. The bottom layer, a hydrogen‐bonding complexed polymer nanoparticle (HCPN) membrane, is fabricated by complexing poly(acrylic acid) and poly(vinylpyrrolidone) into well‐dispersed nanoparticles through hydrogen bonding. This HCPN membrane selectively impedes VOC transport while allowing water to pass. The top layer is an in situ‐grown photothermal membrane that absorbs solar energy, converting it into heat to drive the water evaporation process. Together, the two layers enable efficient separation and evaporation. This dual‐layer solar evaporator demonstrates unprecedented performance, achieving a water evaporation rate of 2.18 kg m ⁻² h ⁻¹ under 1 sun irradiation and over 98% rejection to VOCs. The system maintains stability during 30‐h continuous operation and performs effectively under real sunlight conditions. With its high efficiency, stability, and adaptability to real‐world conditions, this solar evaporator offers a promising solution for providing safe, clean water in remote and underserved areas.