Biomimetic hydrophilic CuO-nanocluster/nanofibrous thin-film skeleton/hydrophilic CuO-nanocluster architecture membrane for efficient and stable solar water evaporation

Abstract

Developing exquisitely structured light-absorbing materials could be a feasible approach to enhance solar evaporation performance. Herein, a CuO-nanocluster/PVDF-HFP nanofibrous thin-film skeleton/CuO-nanocluster (CPC) architecture membrane was developed via electrospinning, heating, and hydrothermal techniques. The CPC membrane architecture is similar to the triple-layer mesophyll/vein/mesophyll in a natural leaf, whereby mesophyll performs photosynthesis for plant growth and the vein acts as a support skeleton. Similarly, CPC mimicking a leaf structure possesses: (1) upper and lower hydrophilic CuO-nanoclusters to absorb sunlight, promote water supply, and prevent salt crystallization during the evaporation process; and (2) a middle nanofibrous thin-film membrane that acts as a supportive layer. The resulting CPC membrane exhibited an evaporation rate of 1.21 kg m−2 h−1 and 1.06 kg m−2 h−1 for 3.5 wt% saline water and actual industry dye wastewater, respectively. Meanwhile, the CPC membrane was applied in the cycle, continuous, and outdoor evaporation tests. In addition, the CPC membrane displayed impressive mechanical strength and flexibility, making it suitable for the long-term use in practical applications. These findings demonstrate the excellent performance of the CPC membrane for solar water evaporation and should inspire further research on developing dedicated architecture membranes for use in fields such as catalysis, sensing, energy, and other applications.