Simulation Study Of The Effect Of Doping On The Electrical Conductivity Of Carbon Nanomaterials

To improve the poor wettability and charge transfer between carbon nanomaterial,such as carbon nanotube(CNT)and graphene,and heavy metals,the first principles calculations based on density functional theory were performed to study the interactions between CNT/graghene and heavy metals.Firstly the adsorption of Pt atom on capped CNT doped with B/N has been studied.By analyzing the adsorption diatance,adsorption energy,charge transfer and Mulliken population,it was found that B/N doping could both increase the adsorption energy and promote the charge transfer between CNT and Pt.Compared with doping B,doping N at CNT caps could improve the interactions between Pt and CNT more effectively,which would improve the performance of CNT supported Pt catalysts.For graphene supported Pt catalysts,the larger the interaction is,the better the performance of the catalysts is.Therefore,the adsorption properties of Pt atom on intrinsic graphene/vacancy defect graphene(VG)were analyzed.For intrinsic graphene,the adsorption energy and charge transfer between graphene and Pt got the largest value at bridge site,but it was still hard to form stable chemical adsorption.While for VG,the vacancy defect would introduce the localized states near Fermi level.Therefore,the electron deficiency would be formed and the charges in Pt can be transferred to VG,which would increase the electrical contact conductivity and stability of the coupled system.To improve the weak charge transfer between graphene and Au in graphene supported Au catalysts,the adsorption properties of Au atom on Fe-doped graphene had been calculated.The band structure shows doping Fe would form the electron holes on graphene.However,due to the electronegativity of Au atom and the paramagnetisms of Au and Fe,the charge in graphene would further transfer into Au.Compared with intrinsic graphene,the adsorption energy between Fe-doped graphene and Au atom had increased nearly eleven-fold,and the charge transfer also rises by 183.3%.Therefore,doping Fe could improve the electron transport capacity of graphene supported Au catalysts.