Achieving ultrahigh water evaporation using g-C3N4/MoS2/chitosan hydrogel@nickel foam evaporator with low enthalpy and optimized scallion-like structure

Scallion-inspired 3D CMC@NF evaporator was prepared. • Ultrahigh ER of 6.17 kg·m −2 ·h −1 achieved under 1-sun irradiation. • Evaporation enthalpy significantly reduced from 2415 to 828 kJ·kg −1 . • 3D CMC@NF exhibited excellent salt resistance and stable desalination. Due to its ease of operation and minimal environmental impact, solar-driven evaporation technology holds significant potential in addressing the worsening global water crisis. Inspired by the multi-layered coiled scallion, a 3D g-C 3 N 4 /MoS 2 /chitosan hydrogel@nickel foam (CMC@NF) evaporator was fabricated by decorating photothermal g-C 3 N 4 and MoS 2 , along with hydrophilic chitosan onto porous 3D nickel foam. Remarkably, water evaporation enthalpy decreased significantly from 2415 to 828 kJ·kg −1 due to the presence of hydrophilic chitosan. The multi-layered coiled structure of the scallion-like CMC@NF-2 enhances solar reflection and refraction, and enlarges the water evaporation area through its hierarchical interfacial design. Leveraging synergistic material advantages and optimized geometric configuration, the CMC@NF-2 evaporator attained an ultrahigh water evaporation rate of 6.17 kg·m −2 ·h −1 (normalized to the top-irradiation projected area). The CMC@NF-2 system also exhibited outstanding outdoor water evaporation of 74.54 kg·m −2 ·d −1 , an output adequate to satisfy the daily water requirements of 23 adults (based on a standard of 3.2 L·person −1 ·day −1 ). This study significantly enhances the capabilities of existing solar desalination techniques for delivering portable, cost-effective freshwater supplies, and simultaneously provides a thorough physical interpretation and actionable optimization frameworks for CMC@NF-2 systems. Download: Download high-res image (367KB) Download: Download full-size image