A theoretical study on the adsorption of neutral and zwitterionic glycine on an MgO nanotube

摘要

Adsorption of neutral and zwitterionic glycine on MgO nanotubes was studied using a periodic density functional theory-based method. Different types of adsorption (bridging and bidentate) and dissociation (hydrogen weakening and hydrogen dissociation) were calculated with adsorption energy changes in the range of -0.97 to -2.91 eV. These processes also slightly change the electronic properties of the tube by decreasing its HOMO/LUMO energy gap. The Fermi level shifts toward higher energies upon the interactions between neutral glycine and the tube, resulting in a reduced potential barrier of the electron emission for the tube and hence facilitates the field emission.