Multi-gradient structured needle-punched cotton fabric evaporator with chemically loaded MoS2 for efficient solar desalination

Solar interfacial evaporation presents a sustainable solution to global freshwater scarcity. However, conventional evaporator designs are fundamentally limited by an inherent trade-off between thermal localization and water transport, which severely impedes overall performance. To transcend this limitation, we developed a durable three-dimensional evaporator featuring a hierarchically engineered conical pore architecture (denoted MoS 2 /TA-NPF). This architecture was realized by functionalizing a nonwoven needled cotton fabric (NPF) with molybdenum disulfide (MoS 2 ) nanosheets, where tannic acid (TA) served as a versatile adhesive platform to ensure homogeneous nanosheet loading, broadband solar absorption, and robust environmental stability. The functionalized fibrous layers were then configured into a conical structure with a meticulously controlled pore size gradient-precisely tapered from 5 mm at the top to 2 mm at the bottom. This deliberate structural design plays a dual role: it amplifies light harvesting through pronounced multi-scattering effects, while simultaneously enabling synergistic modulation of the thermal field and capillary-driven water supply. Consequently, the evaporator achieved a superior evaporation rate of 2.21 kg·m −2 ·h −1 under 1 kW·m −2 solar irradiation. Moreover, it exhibited exceptional long-term operational stability under high-salinity conditions, with no discernible performance degradation. By seamlessly integrating molecular-scale interface engineering with macroscopic architectural design, this work establishes a novel and robust strategy for developing high-performance, fouling-resistant solar evaporators, thereby advancing their practical deployment in seawater desalination and high-salinity wastewater treatment.