Synergistic defect engineering and water state modulation in GO/Eu-doped SnSe hydrogels for efficient solar desalination

Combining GO with Eu-doped SnSe enables exceptional broadband solar absorption and photothermal conversion. • A porous hydrophilic PAM hydrogel substrate facilitates highly efficient water transport and concurrent photon capture. • Excellent salt rejection and water purification capabilities were demonstrated for seawater and dye-containing wastewater. Solar-driven interfacial evaporation technology has attracted considerable attention as a promising strategy to address global freshwater scarcity. However, existing evaporators often suffer from limited solar spectral absorption and unsatisfactory water transport capabilities. Herein, we propose a hydrogel-based evaporator fabricated by incorporating a composite of graphene oxide/europium-doped tin selenide into a polyacrylamide (PAM) hydrogel. The incorporation of europium ions into SnSe, synergistically combined with graphene oxide, enables highly efficient absorption across the solar spectrum. The hydrophilic PAM hydrogel significantly enhances water transport within the evaporator while promoting multiple internal reflections of sunlight, thereby improving light trapping capability. The resulting system exhibits exceptional evaporation performance, achieving an evaporation rate of 2.25 kg m −2  h −1 and an efficiency of 98.9% under one-sun irradiation. It also demonstrates excellent salt rejection performance, exhibiting its superior performance in water treatment and seawater desalination. The strategy presented in this work, characterized by efficient solar absorption and remarkable water transport, paves the way for advancing sustainable freshwater production technologies. Download: Download high-res image (133KB) Download: Download full-size image