The Migration Properties Research Of Methanol Across The Modified Carbon Nanotube

With the energy problem increasingly serious, new forms of energy get more and more attention. Fuel cells get the attention as efficient and clean energy. Due to the unique structure properties of carbon nanotubes(CNT), using it into fuel cells' catalyst can deeply improve efficiency of fuel cell. However, the migration properties of methanol across the modified carbon nanotube is to be researched. Through molecular dynamics simulation method, we established the physical model about carbon nanotubes modified port and internal migration. Combined with the theory of statistical thermodynamics, we can research the effect of charge, type of functional group and carbon nanotube radius. The main conclusions are as follows.Carbon nanotubes distribute around the methanol solution, and carbon nanotubes can improve the internal mass fraction of methanol. In the literature, the carbon nanotube port, which is usually used in the presence of dangling bonds, is an unstable structure. It needs to be added with functional groups to form a stable structure, which can exist in nature. The port of modified carbon nanotube have the following types:-H,-OH,-COOH. When they are located in carbon nanotubes port, they are carrying a certain charge. If we changed the charge of the atoms, we found that charge have negative effects through the experimental analysis.In the carbon nanotube with the diameter of(6,6)8.14?, methanol is presenting the single chain distribution. With the increase of diameter, methanol present more and more internal rings structure distributing in the carbon nanotubes, and configuration distribution become more turbulent. Through the calculation of the radial density in the interior of the carbon nanotubes can support the experimental conclusion.Using the functional groups –H,-OH,-COOH modified carbon nanotubes, methanol solution are influenced by the carbon nanotubes. Methanol have the almost unanimous amount of getting into and out of carbon nanotubes with the system balancing. Get the following conclusion: when the carbon nanotube diameter is increasing, the number of methanol every ps across three types of functional group functionalization carbon nanotubes is increasing. So the diameter for methanol passing through carbon nanotubes port have a positive impact. Comparing three kinds of functional groups, methanol each ps acorss-H and-OH functionalization of carbon nanotubes were greater than the number of-COOH functionalization of carbon nanotubes. Suggesting that carboxyl port for methanol acorss carbon nanotubes resistance is bigger, and higher than that of hydrogen and hydroxyl.For-H and-OH functionalization of carbon nanotubes, diameter and atoms swing of functional group have mutual influence of methanol diffusion in carbon nanotubes port. Because hydrogen in functional groups fluctuating near the pipe wall is more and focus with small diameter CNT-H, making methanol crossing carbon nanotubes port much more effective than CNT-OH, so with small diameter CNT-OH is more conducive to the spread of the methanol. So with small diameter CNT-OH is more conducive to the spread of the methanol. With large diameter of carbon nanotubes, the scope of the functional scope difference is bigger. Because carboxyl is based with a longer chain length than hydrogen, the effective area of methanol crossing the CNT-OH port is less than the CNT-H in diameter direction. So CNT-H is more conducive to the spread of the methanol with large diameter CNT.