A 3D-printed integrated MXene-based evaporator with a vertical array structure for salt-resistant solar desalination

Abstract

High photo-to-heat conversion efficiency and excellent desalination performance are both urgent requirements for solar evaporators in actual applications. However, due to the limitation of a single structure and material, the traditional 3D evaporator cannot achieve both high efficiency photo-to-heat conversion and rapid salt removal at the same time. Herein, we report a three-dimensional (3D) integrated evaporator using 3D printing technology, which combines polyimide/MXene (PIM) aerogel arrays as the upper layer and polyimide (PI) aerogel lattices as the bottom layer. The PIM aerogel arrays exhibit a high light absorption rate of 91.3%, and the array structure functions as effective thermal confinement that greatly prevents heat loss while allowing steam to escape into the air. The PI aerogel lattices can form multi-directional mass transfer channels for fast water transport and enable rapid salt particle dissolution, thus inhibiting salt accumulation. Consequently, the 3D integrated evaporator displays both a remarkable photo-to-heat conversion efficiency of 99.7% and superior desalination performance under 1 sun illumination. This paper presents a novel insight for designing salt-resistant solar evaporation systems and can help to overcome the dilemma of water scarcity.