石墨烯/碳纳米管复合气凝胶制备及其光热蒸发性能评价

Preparation ofgraphene/carbon nanotube composite aerogel and evaluation of its photothermal evaporation properties

石墨烯作为一种二维碳基纳米材料,具有宽光吸收范围、高的比表面积、优异的导热导电性及机械性能,在光热转换应用方面具有良好前景。为进一步增强石墨烯的吸光性能,减少石墨烯片层间的团聚,引入一维的碳纳米管,采用简单的水热还原法制备了石墨烯/碳纳米管复合气凝胶三维光热材料,其比表面积显著增强、表面更加粗糙,且具有开放的微观孔道结构。扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶红外光谱(FT-IR)等表征发现,石墨烯与碳纳米管实现了有效复合。以紫外-可见-近红外分光光度计(UV-vis-NIR)对材料进行了光吸收能力评价,结果证明石墨烯/碳纳米管复合气凝胶在200~2500 nm区间内吸光度可达92%。将复合气凝胶置于人工海水上进行光热蒸发评价,发现对人工海水的蒸发速率可达2.287 kg·m^(-2)·h^(-1),光热转换效率达96.88%,说明该石墨烯/碳纳米管复合气凝胶具有良好的光热转化性能,在海水淡化方面具有广阔的应用前景。

As a two-dimensional carbon-based nano-material,graphene has wide optical absorption range,high specific surface area,excellent thermal conductivity and mechanical properties.In order to further enhance the light absorption performance of graphene and reduce the agglomeration between graphene sheets,one-dimensional carbon nanotubes are introduced through a simple hydrothermal reduction method to composite with graphene to obtain a three-dimensional graphene-based photothermal material.The specific surface area of the photothermal material is significantly enhanced and the surface becomes rougher.It has open microporous structure as well.The material is characterized and evaluated in desalination of artificial seawater.Scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier infrared spectroscopy(FT-IR)and so on are used to characterize the material,and effective combination between graphene sheets and carbon nanotubes are observed.It is found that the light absorbance of graphene-carbon nanotube composite aerogel could reach 92%in the range of 200-2500 nm through UV-vis-NIR spectrophotometer(UV-vis-NIR)analysis.The evaporation rate of artificial seawater could reach 2.287 kg/(m^(2)·h)when the composite aerogel is used for solar-steam generation,and the photothermal conversion efficiency could reach 96.88%.These results indicate that graphene-carbon nanotube composite aerogel has a good photothermal conversion performance,and would have a broad application prospect in seawater desalination.