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采用分子动力学方法模拟研究气体分子在石墨表面上的吸附和扩散特性,结果表明气体分子在石墨表面上的吸附强度跟石墨中碳原子和气体分子之间的微观作用力密切相关,不同分子在石墨表面上的吸附强度不同.气体分子在石墨表面上的吸附特性符合Langmuir等温吸附模型,压力越高吸附层内分子的密度越高.通过分子的表面扩散系数随着压力的增加而降低的现象以及特定时间内分子运动距离的正常概率分布,发现石墨表面上分子的扩散主要由分子之间的碰撞控制,趋近于体相扩散.分子在石墨表面吸附层内的密度对表面扩散系数的影响非常显著,导致吸附性强的CO2和H2S分子扩散系数要明显低于吸附性弱的CH4和N2分子.“,”The adsorption and diffusion characteristics of gas molecules on graphite surface are investigated by molecular dynamics simulations.The results show that the adsorption intensity of gas molecules on graphite surface is related to the atomic interactions between gas molecules and carbon atoms in graphite;different gas molecules present distinct adsorption intensities on graphite surface.The adsorption characteristics can be described by the Langmuir isothermal adsorption model,where the molecular number density in the adsorption layer increases with increasing gas pressure.From the decreasing diffusion coefficients with increasing gas pressure and the normal probability distribution of molecular moving distance in a certain time period,it is concluded that the gas diffusion on graphite surface is mainly controlled by the molecular collisions and approaches the bulk diffusion phenomenon.Accordingly,the molecular number density in the adsorption layer has a great effect on the surface diffusion coefficients,resulting in the obviously lower diffusion coefficients of CO2 and H2S molecules with stronger adsorption intensities than those of CH4 and N2 molecules with weaker adsorption intensities.