A self-healing, deformation-resistant MXene double-network hydrogel for stable solar-driven interfacial evaporation

Abstract

Solar-driven interfacial evaporation (SDIE) is an eco-friendly and sustainable technology for desalinating water. Hydrogel-based composite evaporators are effective in resisting salt, but often suffer from reduced shape stability and diminished water transport capability during dehydration and rehydration cycles, which undermines their long-term performance in photo-evaporators. Here, we developed a long-term stable MXene-carrageenan/polyacrylamide (MXene-CA/PAAm) hydrogel evaporator. This device integrates an MXene film for efficient photothermal conversion with a double-crosslinked, high-strength, deformation-resistant, self-healing hydrogel for water supply. A dehydration/rehydration cycling test was developed to evaluate the shape stability and water absorption capacity of hydrogel-based evaporators. The MXene-CA/PAAm hydrogel evaporator operated continuously for 360 hours without performance decrease, achieving an average evaporation rate of 1.78 kg m² h⁻¹ under 1 sun illumination. This study presents a novel approach to creating double-network hydrogel evaporators, enhancing stability and durability, and advancing desalination technology.