Desert Plant Inspired Hierarchical Nanofibrous Membranes for Integrated Solar Desalination and Heavy Metal Remediation

ABSTRACT Freshwater scarcity is a global challenge, increasingly compounded by heavy metal contamination of water systems. Solar‐driven interfacial evaporation has emerged as a compelling solution owing to its energy efficiency and environmental benignity. Inspired by a desert plant − Alhagi camelorum , we develop a biomass‐based composite nanofibrous membrane to facilitate the capture of heavy metals in contaminated water and solar‐driven water evaporation. Following the electrospinning of cellulose, chitosan, and an indium‐based metal–organic framework (MIL‐68(In)), the in situ growth of copper oxide (CuO) nanoflowers is realized on the nanofiber network. The hierarchical porous network − assembled from interwoven nanofibers decorated with roughened nanoflowers − enables exceptional broadband light trapping. Meanwhile, the CuO nanoflowers serve as a catalytic interface, activating interfacial water molecules through efficient charge transfer that lowers the dissociation energy barrier, thereby enabling rapid and stable vapor generation. Under one‐sun irradiation (1 kW m − 2 ), the membrane achieves an evaporation rate of 2.80 kg m − 2 h − 1 and a photothermal conversion efficiency of 98.95%. Density functional theory calculations elucidate the atomistic and electronic mechanisms underpinning this exceptional performance. This biomass‐derived photothermal membrane simultaneously combines the capture of heavy metals and water purification, representing a meaningful advance in water purification and resource recovery.