Synergistic Dual‐Mechanism Localized Heat Channeling and Spectrum‐Tailored Liquid Metal Hydrogels for Efficient Solar Water Evaporation and Desalination

Abstract

AbstractPhotothermal hydrogels featuring broadband light absorption abilities and highly hydrated networks provide an appealing mass‐energy transfer platform for water evaporation by using solar energy. However, the targeted delivery of solar heat energy to power the water evaporation process remains challenging. Herein, enlightened by metal‐phenolic coordination chemistry and camouflaged architecture, photothermal hydrogels with dual‐mechanism vaporization structure are tactfully designed via a rational interfacial engineering and integration strategy to enable near‐µm heat confinement and highly efficient light‐to‐heat conversion ability. The spectrum‐tailored liquid metal droplet (LMGAs‐FeIII) and optimized carbon‐wrapped silver nanowire sponge (Ag@C750) are integrally built as photothermal promotors/channels and jointly embedded into a highly hydratable poly(vinyl alcohol) hydrogel, denoted as PALGH, to synergistically boost water molecule activation and interfacial vaporization behavior by triggering robust photothermal performance. As a result, under one sun irradiation, the all‐embracing PALGH hydrogel evaporation system achieves a brine evaporation rate to a high level of 3.47 kg m−2 h−1, and >19 L m−2 clean water of PALGH is ideally delivered daily when purifying natural seawater. This work offers not only a rational design principle to create sophisticated photothermal materials but also replenishes insight into solar heat generation and water transportation in a cross‐media system.