Study On Hydrogen Storage Mechanism Of Cup-stacked Carbon Nanotubes

In the global context of the exhaustion of traditional fossil energy and the aggravation of environmental pollution,hydrogen energy,as the most environmentally friendly low-carbon energy,has become the focus of world attention.However,in the process of hydrogen energy development and utilization,hydrogen storage is the main bottleneck of hydrogen energy development.Among them,the physical adsorption type hydrogen storage material with porosity,large specific surface area and instantaneous rich hydrogen stripping quantity etc,from the perspective of carbon materials,the structure of cup-stacked carbon nanotubes(CSCNT)has obvious advantages in the carbon material,but the structure is still in exploring in hydrogen storage mechanism,thus the article choose cup-stacked carbon nanotubes for hydrogen storage mechanism research.Firstly,molecular dynamics and Monte Carlo method in theoretical method are introduced respectively in detail,and their basic ideas and solutions are summarized.In this paper,Materials Studio software is selected to simulate the adsorption mechanism,mainly using the force module and sortation module of MS software,which are used to explain the adsorption mechanism of hydrogen molecules in the CSCNT at the micro level.Secondly,the mechanism of hydrogen molecules on the external surface adsorption sites of a single CSCNT is studied,and the hydrogen storage effect of CSCNT under different structural and physical parameters is also explored.Among them,structural parameters include cone apex angles of 38.9 °,60 °,83.6°and 112.9°,and layer spacing between stacking cups of 3.35?,4?,5?,6? and 7?.The physical parameters include pressures of 1-10 MPa and the temperatures of 77 K,273K and 298 K.The excess adsorption capacity,the adsorption heat and the hydrogen density distribution are used to evaluate the hydrogen adsorption performance of the CSCNT.The results show that the hydrogen storage rate of CSCNT can reach the maximum value under the conditions of 77 K and 3MPa,and at the same time,appropriately increasing thelayer spacing is helpful to improve the adsorption capacity.Finally,the mechanism of hydrogen molecules acting on the planar arrangement of CSCNT is studied.The potential energy effect of VDW distance and arrangement mode between different tube bundles on hydrogen molecules are mainly discussed.Among them,the contrapuntal CSCNT van der Waals(VDW)distance is 3.35?,6? and 10?,and the arrangement mode is contraposition arrangement,triangle arrangement and square arrangement.At the same time,the VDW distance of CSCNT in different arrangement is 3.35-12?,and the influence of different average diameters of CSCNT in square arrangement on hydrogen storage performance is also explored.The results show that the adsorption of hydrogen molecules by CSCNT is more stable in the triangular arrangement,and the interception of hydrogen molecules at different positions at the same cone apex Angle had little effect on hydrogen storage rate,but the closer the interception position is to the top,the stronger the adsorption of hydrogen molecules is.