Chitosan/multilayered MXene Nanocomposites Loaded in 3D Nitrogen‐Doped Carbon Networks for Seawater Desalination with Highly Efficient Photothermal Conversion

Abstract Sunlight, as one of the inexhaustible green energy sources, is attracting rising attention, particularly with the rapid depletion of traditional fossil fuels nowadays. Chitosan (CHT) is an abundant natural product that can be converted into N‐doped porous carbon which has a strong light absorption ability. Herein, chitosan is employed with the accordion‐like multilayered mMXene (mMXene) to fabricate the 3D thermally insulated and low‐cost composites using melamine foam (MF) as a template. The obtained MF/CHT/mMXene (MCM) composites with different mass ratios of mMXene/chitosan are then subject to a simple annealing treatment at 500 °C for 2 h to afford 3D and self‐floating carbonized carbonized MF/CHT/mMXene (CMCM) composites. The CMCM‐1 obtained with mass ratio of CHT/mMXene at 1:1 displays low thermal conductivity, high hydrophilicity, and good light absorbance. When it is utilized as the evaporator of pure water and seawater, its evaporation rates can reach at 1.554 and 1.428 kg m⁻² h⁻¹ under 1 kW m⁻² irradiation and the photothermal conversion efficiency can reach at 89.8%. In addition, the CMCM‐1 composite also displays excellent desalination ability, self‐desalination ability, good cycle stability, and reliable safety performance. Combining these advantages, CMCM‐1 composite may have potential practical applications for seawater evaporation and wastewater treatment, etc.