Density functional calculations of nickel, palladium and cadmium adsorption onto (10,0) single-walled carbon nanotube

Adsorption of three heavy metals (Ni, Pd, Cd) onto (10,0) single-walled carbon nanotube (SWCNT) was investigated using density functional theory (DFT). Metals were adsorbed to both inside and outside of SWCNT and their structures and electronic properties [e.g., band structures and density of states (DOS)] were calculated and compared. The effects of substituting one carbon atom of the nanotube with these metals were also investigated. Formation energy results showed that adsorption inside and outside the nanotube is energetically favored. Significant changes were observed in the electronic properties of SWCNT after Ni and Pd adsorptions, and the nanotube changes from being a semi-conductor to a metallic conductor. However, the conductivity did not change markedly after Cd adsorption, indicating its physical adsorption to the nanotube. Spin polarized calculations showed that nickel adsorption inside and outside SWCNT induces magnetization of the system. Different electronic properties were obtained after adsorption of Pd atoms to different sides of SWCNT. Partial DOS were also applied to interpret the changes in electronic properties more precisely.