Cao Pei, Zhao Liming, Zhang Jian, Zhang Liwen, Yuan Peng, Zhang Yongyi, Li Qingwen
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230000, China.
Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China.
ACS Appl Mater Interfaces. 2021 Apr 28;13(16):19109-19116. doi: 10.1021/acsami.0c21831. Epub 2021 Apr 14.
The emerging interface solar-thermal water evaporation has been widely studied to solve fresh water shortage because of its high solar-thermal conversion efficiency, environmental friendliness, and low cost. However, traditional water evaporation systems inevitably lose heat to the environment, which not only greatly affects the water evaporation rate but also hinders their practical applications. In this work, an interface solar-thermal water evaporation system with enhanced heat localization, which is combined by a hydrophobic carbon nanotube (CNT) film (heating layer) and hydrophilic polyvinyl alcohol (PVA)/CNT foam (evaporating layer), is demonstrated. Under solar irradiation, the temperature of the hydrophobic CNT film is higher than that of the hydrophilic PVA/CNT foam due to the differences in wettability, so the thermal energy in the CNT film can be continuously transferred to the PVA/CNT foam evaporator, forming a gradient heating effect and greatly increasing the water evaporation rate. As a result, the water evaporation rate can reach 4.2 kg m h under a solar illumination of 1 kW m, which is among the highest water evaporation rate levels. More importantly, this water evaporation system structure is simple, can be easily scaled up, and has gradient applicability to other photothermal materials, which provides a route to improve the interfacial solar steam evaporation rate.
新兴的界面太阳能-热蒸发技术因其高太阳能-热转换效率、环境友好性和低成本，已被广泛研究以解决淡水短缺问题。然而，传统的水蒸发系统不可避免地会向环境散热，这不仅极大地影响了水蒸发速率，还阻碍了它们的实际应用。在这项工作中，展示了一种具有增强热定位功能的界面太阳能-热蒸发系统，该系统由疏水性碳纳米管（CNT）薄膜（加热层）和亲水性聚乙烯醇（PVA）/CNT泡沫（蒸发层）组合而成。在太阳辐射下，由于润湿性的差异，疏水性CNT薄膜的温度高于亲水性PVA/CNT泡沫的温度，因此CNT薄膜中的热能可以持续传递到PVA/CNT泡沫蒸发器，形成梯度加热效应并大大提高水蒸发速率。结果，在1 kW m²的太阳光照下，水蒸发速率可达4.2 kg m⁻² h⁻¹，这处于最高水蒸发速率水平之列。更重要的是，这种水蒸发系统结构简单，易于扩大规模，并且对其他光热材料具有梯度适用性，这为提高界面太阳能蒸汽蒸发速率提供了一条途径。
