Natural Fiber@MXene-Engineered Chitosan Aerogels: Thermodynamic-Transport Synergy for Solar-Driven Hypersaline Interfacial Evaporation.

Enhancing interfacial evaporation rates and optimizing energy utilization remain critical challenges in solar-driven steam generation. Natural fiber@MXene-engineered chitosan aerogels with hierarchically oriented channels to achieve high-efficiency solar-driven steam generation are developed. The kapok fiber@MXene core-shell units (MKFs) construct photon-entrapping topological networks that enhance light absorption while simultaneously reinforcing the aerogel's structural integrity and durability for practical applications. The aerogel's oriented microchannels establish thermodynamic potential gradients, facilitating spontaneous capillary-driven water replenishment and environmental thermal harvesting. Both experimental results and COMSOL multiphysics simulations systematically demonstrate that hierarchical pore channels enhance water transport, improve solar-thermal/environmental energy synergy, and promote the downward diffusion of concentrated ions from the evaporation surface, achieving an evaporation rate up to 4.40 kg m h with efficient salt rejection. Long-term outdoor tests with various corrosive wastewater solutions further validate the aerogel's durability in solar-driven interfacial evaporation. This study provides a theoretical foundation for understanding the interrelation between solar energy absorption, water transport, and salt diffusion in aerogel evaporators with hierarchical fiber-pore architectures.