Two-Dimensional Selenium Nanosheet-Based Sponges with Superior Hydrophobicity and Excellent Photothermal Performance

Photothermally assisted superhydrophobic materials play an important role in a variety of applications, such as oil purification, waste oil collection, and solar desalination, due to their facile fabrication, low-cost, flexibility, and tunable thermal conversion. However, the current widely used superhydrophobic sponges with photothermal properties are usually impaired by a high loading content of photothermal agents (e.g., gold or silver nanoparticles, carbon nanotubes), low photothermal efficiency, and require harmful processes for modification. Here, a one-pot, simple composite consisting of two-dimensional (2D) selenium (Se) nanosheets (NSs) and commercially used melamine sponge (MS) is rationally designed and successfully fabricated by a facile dip-coating method via physical adsorption between 2D Se NSs and MS. The loading content of 2D Se NSs on the skeleton of the MS can be well controlled by dipping cycle. The results demonstrate that after the modification of 2D Se NSs on the MS, the wettability transition from hydrophilicity to hydrophobicity can be easily achieved, even at a very low loading of 2D Se NSs, and the highly stable photothermal conversion of the as-fabricated composites can be realized with a maximum temperature of 111 ± 3.2 °C due to the excellent photothermal effect of 2D Se NSs. It is anticipated that this composite will afford new design strategies for multifunctional porous structures for versatile applications, such as high-performance solar desalination and photothermal sterilization.