Study On Hydrogen Absorption Mechanism Of Cup-shaped Carbon Nanotubes Loaded With Platinum Metal

Hydrogen energy is one of the most promising secondary energy sources in the21 st century.Due to its advantages of non-polluting and high combustion calorific value,it is known as the green energy of the 21 st century.Among them,hydrogen storage technology is a key link in the development and application of hydrogen energy.When using carbon-based materials to absorb hydrogen,the cup-shaped carbon nanotubes(CSCNT)have better hydrogen storage characteristics than conventional carbon nanotube hydrogen storage materials in terms of structure.Considering the limitation of hydrogen storage of carbon-based materials,in this study,the method of modification,that is,loading platinum metal,was used to improve the hydrogen storage performance of cup-shaped carbon nanotubes.In order to better discuss and analyze the hydrogen storage characteristics of modified carbon nanomaterials,this study established a corresponding model and used Gaussian,VMD and other software to analyze the model storage after loading platinum metal from the perspective of charge,electrostatic potential and spin density.The reasons for the changes in hydrogen performance,and the optimal adsorption sites after the optimization of hydrogen absorption have been studied.In the analysis of the charge and electrostatic potential before and after the hydrogenation of the loaded platinum metal,it was found that a certain change occurred in the number of charges before and after hydrogen absorption,which proved that the charge transfer occurred between the adsorbed hydrogen molecules and the platinum atoms of the nanotube clusters.The process of absorbing hydrogen.The electrostatic potential near the metal-loaded area changes greatly,and one or more extreme points with darker colors are generated,which indicates that the presence of metal makes the model generate more active adsorption sites,which will be more favorable for hydrogen sorption.Observation and analysis of the spin density before and after the hydrogenation of the loaded platinum metal showed that a certain active area is generated near the metal after the metal is loaded,which is conducive to the adsorption of hydrogen molecules.After adding hydrogen molecules,its active area becomes smaller,indicating that it forms a more stable structure than before through the interaction with hydrogen molecules.The analysis of the change of the atomic distance and the density of states after hydrogenation of the supported platinum metal found that in the comparison of all the loading sites,the loading of the metal at the center of the bridge site is quite different than that of other loading sites,and its performance is greater.The distance between hydrogen atoms,the smaller the distance between metal and hydrogen atoms,and the bonding interval are more consistent,and the left boundary of the energy level interval has a larger value.The statistical analysis of the binding energy revealed that the binding energy of hydrogen molecules showed different degrees of numerical difference.Generally speaking,the absolute value of the binding energy of hydrogen molecules at the loading site of the bridge position is the largest,which means that the binding energy of hydrogen molecules is the same.In the case of benzene ring,loading platinum metal above the bridge position will have the best effect on the adsorption of hydrogen molecules.This corresponds to the results of several aspects discussed in this paper,and is also consistent with the results of previous studies.From the point of view of the selected positions of the upper,middle and lower three benzene rings,it can be seen from the histogram that the intermediate bridging load point is relatively the best in terms of binding energy for the platinum metal load.