Cellulose acetate membrane incorporated with graphite-MoSe₂ hybrid for photothermal steam generation and solar...

The growing global population drives increasing freshwater demand, making sustainable seawater desalination critical. This study presents an electrospun biodegradable cellulose acetate (CA) membrane for solar water evaporation. To improve light absorption, photothermal additives, graphite and MoSe₂, were incorporated into the CA membrane. The properties and water production performance of neat CA, graphite-incorporated CA, MoSe₂-incorporated CA, and graphite-MoSe₂ hybrid-incorporated CA membranes were compared. Tensile toughness, vital for membranes under harsh conditions, was highest in the MoSe₂-incorporated CA membrane (103.17 ± 8.54 kJ m^-3), surpassing neat CA (88.58 ± 0.33 kJ m^-3). The graphite-MoSe₂ hybrid membrane (CA/G-MoSe₂) exhibited the highest Young's modulus (11.46 ± 0.40 MPa) compared to neat CA (8.55 ± 0.33 MPa). CA/G-MoSe₂ also demonstrated strong hydrophobicity (water contact angle 139.54 ± 0.44°), enabling it to self-float on water and artificial seawater. The hybrid significantly enhanced light absorption, yielding a light-to-thermal conversion efficiency of 89.91 %. Evaporation rates reached 1.546 ± 0.038 kg m^-2h^-1 (water) and 1.300 ± 0.047 kg m^-2 h^-1 (artificial seawater) under ~1 kW m^-2 infrared light, with a 99.94 % reduction in salt ion concentration. Under sunlight, the solar desalination rate of the composite membrane was 1.730 ± 0.041 kg m^-2 h^-1. These results demonstrate that the CA/G-MoSe₂ membrane is a promising, sustainable solar interfacial evaporator for freshwater production.