First Principles Investigation Of The Adsorption On Boron-or Nitrogen-doped Carbon Nanotube And Graphene

The carbon nanostructures (CNS) have attracted considerable interests for potential applications in the catalyst composite field. They excellent physical and chemical properties have attracted the interest and attention of many researchers. Since the researchers found the hydrogen storage potential of carbon nanomaterials in1997, they attracts many researchers in hydrogen storage research. The B/N-doped and metal adsorption have a very significantly modified on the adsorption、electrical and magnetic properties.For the adsorption of hydrogen gas and transition metals, this paper has establisded the B/N-doped carbon nanotubes、graphene adsorbed hydrogen or transition metal ideal model. And first principles method based on density functional theory (DFT) plane wave pseudopotential method and generalized gradient approximation calculated by Quantum ESPRESSO package.Therefore, we have calculated the electronic properties of B/N-doped4A carbon nanotubes,(3,3)、(4,2)、(5,0),and in-depth studied hydrogen atom and molecular adsorption to find adsorption stability of B/N doping structures, and band type. On the other hand, the adsorptions of third-row transition metal atoms (Sc--Cu) on the boron-or nitrogen-doped (3,3) carbon nanotubes and graphene are investigated. And bond lengths, binding energies, and magnetic moments are calculated in this work.The hydrogen adsorption studies show that the B-doped structure is more stable than N-doped structure, and they have the P-type and N-type dopant respectively. The (3,3) and (5,0) CNT have a poor performance on the hydrogen atoms adsorption. But the B-doped can improve the hydrogen atoms adsorption on the (4,2) and graphene. And all systems for the adsorption of hydrogen molecules are extremely small. In the study of metal adsorbed, the results of binding energies suggest that nitrogen-doping could enhance the metal adsorption on carbon nanotubes, while boron-doping does not effectively enhance the metal adsorption, but on the graphene, boron-doping could enhance the metal adsorption, while nitrogen-doping could weaken the metal adsorption. Analysis of electronic population and charge density difference of representative atoms on the (3,3) systems indicate that nitrogen-doping causes charge re-distribution and the improved metals adsorption on carbon nanotubes by nitrogen-doping can be attributed to the strong interactions between metal atoms and C atoms. But in the graphene case, the interactions between metal atoms and B atom are more stronger. In addition, the transition metal adsorption also caused the magnetic change.