Superwetting MAX@SiO2 coatings with high photothermal conversion performances for efficient seawater desalination and anti-/de-icing

We develop layered MAX (e.g., Ti3AlC2, Ti3AlCN, Ti2AlC, Ti2AlN) into novel photothermal silica-deposited MAX (MAX@SiO2) composites and coatings for efficient seawater desalination and anti-/de-icing, by combining their strong optical absorbance capacity covering UV–Vis-NIR regions with unique surface wettability. The water evaporator with a unique gradient superhydrophilicity-hydrophilicity-hydrophobicity-superhydrophobicity is achieved by incorporating the as-synthesized hydroxyl- and methyl-modified MAX@SiO2 composites into porous melamine foam (MF). By combining the unique gradient wettability with porous structure and strong optical absorbance, the representative MAX@SiO2 evaporator displays excellent seawater desalination performance with high water evaporation rates of ∼2.19 and 3.45 kg m−2 h−1 under 1.0 and 2.0 sun irradiation, respectively. The photothermal water evaporation efficiency can reach to 91.2 % under 1.0 sun illumination. Besides, by sequential spray-depositing resin-based primer and MAX@SiO2 top-coat on glass slides and insulators, the as-achieved superhydrophobic (SH) photothermal coatings displayed excellent anti-icing and de-icing performances. The procedures described here enable a convenient and novel strategy to develop micro-nanocomposites and multifunctional coatings with strong photothermal conversion ability, which would shed light on promising potentials in energy conversion and photo-thermal applications including solar freshwater generation, sewage purification, and anti-/de-icing.