缺陷碳纳米管作为Pt的高效载体的理论研究

Theoretical study of the defect carbon nanotubes as efficient support materials for platinum

采用密度泛函理论,分别以原始碳纳米管(carbon nanotube,CNT)、单空位(single-vacancy,SV)缺陷碳纳米管、Stone-Wales(SW)缺陷碳纳米管为载体,对Pt原子在这几种载体内外表面的吸附行为进行了理论研究.通过计算吸附能、电荷,分析前线分子轨道和态密度,分别找出每种载体的内外吸附结构中最稳定的吸附构型,分析当缺陷存时对于碳纳米管负载Pt催化剂稳定性的影响.计算结果表明,Pt在原始碳纳米管内部吸附结构比外部吸附结构稳定,当以缺陷为载体时,Pt在碳纳米管外部吸附反而比内部更有利,且缺陷的存在使得吸附结构比原始碳纳米管更稳定,其中以SV缺陷为载体的结构无论是内吸附还是外吸附,对Pt的固定作用都是最好的.因此,可以通过在碳纳米管中引入SV缺陷结构来提高Pt催化剂的稳定性和耐久性.

In this paper,we used the original carbon nanotubes（ CNT） and the single-vacancy（ SV） defects and Stone-Wales（ SW） defects as the supports to study the adsorption behavior of Pt atom on the inner and outer surfaces of carbon nanotubes.The most stable adsorption structures inside and outside the carbon nanotubes have been found by calculating the adsorption energy and the charge,analyzing the front molecular orbital and the density of states etc.Furthermore,we analyze the influence of the defect on carbon nanotubes and on stability of Pt@ carbon nanotubes.The calculated results show that the internal adsorption structure of the CNT is more stable than the external adsorption structure.The outer side adsorption on the defective carbon nanotubes is more favorable to the adsorption of Pt than the inside,and the presence of defects make the adsorption structure more stable than the CNT,and the structure with SV defects as the supports has the best fixation to Pt.Therefore,we can improve the stability and durability of the Pt catalyst by introducing the SV defect structure into the carbon nanotubes,it can not only improving the stability of the carbon nanotube carrier but also improving the efficiency of the Pt catalyst.