S/O-Functionalities on Modified Carbon Materials Governing Adsorption of Water Vapor

详细信息    查看全文

• 作者：Jing Xiao ; Zhenlong Liu ; Kyungsoo Kim ; Yongsheng Chen ; Jian Yan ; Zhong Li ; Weilong Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：November 7, 2013
• 年：2013
• 卷：117
• 期：44
• 页码：23057-23065
• 全文大小：454K
• 年卷期：v.117,no.44(November 7, 2013)
• ISSN：1932-7455

文摘

This work investigated the effect of surface functionalities of various unmodified and mildly modified carbon materials on the adsorption of water vapor at different relative humidity (RH) ranges. The adsorption isotherms of various carbon adsorbents were measured on a dynamic vapor sorption system. The carbon adsorbents were characterized by N₂ adsorption test, scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), Boehm titration, oxygen K-edge X-ray absorption near-edge structure (XANES) spectroscopy, temperature programmed desorption (TPD), and infrared (IR) spectroscopy. It is suggested that oxygen functional groups on the carbon surface play a critical role for water vapor adsorption. With the modification of carbon surface by (NH₄)₂S₂O₈ in H₂SO₄, 鈭扖OOH, and S鈺怬 functional groups are introduced on the carbon surface. The surface functionalities, in particular 鈭扖OOH and S鈺怬 functional groups on carbon surface, may govern the adsorption of water vapor at low RHs (RH < 40%); while the other types of oxygen functional groups, such as 鈭扥H, may contribute to the adsorption of water vapor at medium or high RHs. At high RHs (>70%), textural property, especially pore volume of carbon materials may govern the dehumidification capacity via pore filling mechanism, only if sufficient oxygen functional groups are present on carbon surface.