A First-principles Study on the Gas Sensitivity of Metal-loaded Graphene with an Atomic Vacancy to O2

In this work, adsorption energies, geometrical and electronic structures for adsorption systems of O-2 at metal-loaded graphene (M-Gra) and metal-loaded defective graphene (M-D-Gra) (M = Ni, Pd, Pt and Al) surfaces are studied using a GGA-PW91 method. Calculated results show that loaded M make the interaction between O-2 and the graphene surface change from physical to chemical adsorptions, band gaps of M-Gra systems after the O-2 adsorption change, and the Ni-loaded Gra has the highest sensitivity to O-2. For O-2-M-D-Gra systems, interactions between O-2 and the M-D-Gra surfaces are chemical, similar to the O-2-M-Gra systems, and loaded Pt and Al have the strongest effect on the sensitivity of D-Gra to O-2 . The M loads at the perfect Gra and D-Gra surfaces make the interactions between O-2 and the surfaces have obvious charge transfer. This work would provide a valuable guidance on the gas sensitivity study of graphene to O-2.