摘要
碳纳米管及石墨烯具有高比表面积、高化学稳定性以及高耐蚀性等优点,被认为是一种理想的吸附材料。分子模拟技术的发展和应用丰富了人们对吸附机理研究的方式,而简单气体吸附体系的吸附机理研究对吸附理论的发展有着重要的推动作用。本文以单壁碳纳米管(SWCNT)-N_(2)吸附体系为研究对象,首先通过透射扫描电镜和氮气吸/脱附测试对所选用碳纳米管的微观孔形貌及吸/脱附等温线进行了表征,然后根据对应孔径参数采用巨正则蒙特卡罗方法对该体系的吸附过程进行了分子模拟,并详细研究了碳纳米管孔径和温度对该体系吸附行为的影响。结果显示,SWCNT孔径越小,吸附能力则越强;孔半径为0.746nm的SWCNT的吸附体系发生凝聚相变的临界温度为66K。通过对等量吸附热进行计算发现,孔半径0.746、1.15、1.56和1.83 nm的SWCNT-N_(2)吸附体系对应的初始固-液等量吸附热分别为10.9、9.2、8.6和8.4 kJ/mol。67.5K时,孔半径1.56和1.83 nm的吸附体系的等量吸附热有热峰出现。
Carbon nanotubes and graphene are considered as ideal adsorption materials due to their high specific surface area, high chemical stability and excellent corrosion resistance. The development and application of molecular simulation technology have enriched the manners to study adsorption mechanisms, and adsorption behaviors of simple gas adsorption system play an important role in promoting the development of adsorption theory. Based on single-walled carbon nanotubes(SWCNT)-N_(2)itrogen adsorption system, firstly, the micro-pore morphology of the selected carbon nanotubes was analyzed by transmission scanning electron microscope and Nadsorption/desorption test;then the adsorption process was simulated via Grand Canonical Monte Carlo method according to the corresponding aperture parameters. The effects of carbon nanotube pore size and temperature on the adsorption behavior of the system were studied in detail. The results showed that SWCNT with the smaller pore radius has a stronger adsorption capacity. The critical temperature for condensation phase transition of the SWCNTs with pore radius of 0.746 nm is 66 K. It is found that the initial solid-liquid isosteric heats are 10.9 kJ/mol, 9.2 kJ/mol, 8.6 kJ/mol and 8.4 kJ/mol corresponding to the adsorption systems with the pore radii of 0.746 nm, 1.15 nm, 1.56 nm and 1.83 nm, respectively. At 67.5 K, the isosteric heat peaks are both obviously indicated with nanotube pore radii of 1.56 nm and 1.83 nm.
作者
赵明慧
刘忠军
姬帅
刘晨
敖庆波
Zhao Minghui;Liu Zhongjun;Ji Shuai;Liu Chen;Ao Qingbo(College of Materials Science and Engineering,Xi'an Shiyou University,Xi'an,710065;State Key Laboratory of Porous Metal Materials,Northwest Institute for Non-ferrous Metal Research,Xi'an,710016)
出处
《化学通报》
CAS
CSCD
北大核心
2022年第7期867-875,共9页
Chemistry
基金
西安石油大学校青年创新团队项目(2019QNKYCXTD12)
西安石油大学研究生创新与实践能力培养计划立项项目(YCS21113152)资助
陕西省教育厅科学研究计划服务地方专项(20JC028)
陕西省自然科学基金面上项目(2021JM-410)。
关键词
单壁碳纳米管
吸附
蒙特卡罗
等量吸附热
凝聚相变
SWCNT
Adsorption
Monte Carlo
Isosteric adsorption heat
Condensation phase transition
