Bacterial cellulose-based film with self-floating hierarchical porous structure for efficient solar-driven interfacial evaporation.

Interface solar water evaporation is a mean of rapidly evaporating water using solar energy. However, it is still a challenge to obtain solar evaporators with simple assembly, durability and high photothermal performance. Here, we demonstrated an effective post foaming strategy for treating nitrogen-doped reduced graphene oxide/bacterial cellulose film (F-NRGO@BC) prepared by a simple in situ culture method. The composite film contains hierarchical porous structure and bubbles on the film, achieving an integrated self-floating interface evaporator with excellent light absorption (96.5 %) and high toughness (200.18 kJ m-3). Porous structure and low enthalpy of F-NRGO@BC make a high evaporation rate of 1.68 kg m-2 h-1 and a low thermal conductivity of 0.644 W m-1 K-1 to ensure effective energy efficiency and heat insulation. This design of controlling surface morphology and internal structure provides a novel way for large-scale preparation and high-performance evaporator.