Sustainable MXene/PDA hydrogel with core-shell structure tailored for highly efficient solar evaporation and long-term desalination

Solar evaporation is an effective means to solve the scarce of fresh water resources. The developed solar evaporator has the disadvantages of low evaporation rate, poor mechanical performance, difficulty in long-term evaporation, and insufficient water purification capacity. Herein, we have developed a core-shell structure hydrogel solar evaporator taking MXene/PDA as the photothermal material. The hydrogel matrix possesses self-healing and remoldability, which is sustainable and in line with the theme of current material development. The prepared core-shell structure hydrogel showed excellent properties, with a compressive stress of 0.4 MPa and the evaporation rate is as high as 3.02 kg m −2 h −1 , and the evaporation efficiency is 94.7 % under 1 sun illumination, which is better than most of the previously reported solar evaporators. Through the durability experiment in simulated seawater, the long-term desalination ability was verified. Simultaneously, the solar evaporator also exhibits various functions such as dye resistance, and heavy metal ion resistance. The core-shell structure solar evaporator shows great potential in long-term seawater desalination and water purification. Furthermore, it provides a promising strategy for the structural design of solar evaporators in the future. • A two-step method was used to customize the core-shell structure hydrogel. • The nanocomposite material MXene/PDA shows excellent light-to-heat conversion efficiency. • The water state in hydrogel has been investigated. • The evaporation rate is as high as 3.02 kg m −2 h −1 , and the evaporation efficiency is 94.7 % under 1 sun illumination.