Photothermal-responsive tungsten bronze/recycled cellulose triacetate porous fiber membranes for efficient light-driven interfacial water evaporation

Solar-driven steam generation is a common strategy for clean water production and wastewater treatment. Tungsten-oxide-based composites have lately gained significant attention due to their capability of absorbing near-infrared (NIR) light and transforming it into heat for evaporating water. The strong surface plasma resonances and intervalence charge transfer of these composites result in high photoabsorption in a wide NIR spectrum. Here, we fabricate combined rubidium tungsten bronze and recycled triacetate cellulose (RbxWO3/rTAC) porous fiber membranes without any supporting components, via solution electrospinning. The as-prepared RbxWO3/rTAC porous fiber membranes float on the water surface because of their low weight and hydrophobicity. RbxWO3 (0, 5, 10, 15, and 20 wt%) was incorporated into a recycled triacetate cellulose (rTAC) matrix, and its efficiency for light-driven water evaporation was calculated. The rTAC polymer, significantly contributes toward its desirable wetting properties and its porous structure, which are favorable for solar steam generation. The results showed that the evaporation efficiency of RbxWO3/rTAC fiber membranes with an optimized 15 wt% of RbxWO3 nanorods reached 90.4 +/- 2.1%, which is considerably greater than that of pure rTAC fiber membranes and of pure water. A great potential has also been proved by simulating solar exposure, with a water conversion efficiency of approximately 73.6%. Thus, RbxWO3/rTAC photothermal fiber membranes can find applications in water purification, desalination, and steam power generation.