Adsorption behavior of graphene-like ZnO monolayer with oxygen vacancy defects for NO2: A DFT study

As a new two-dimensional (2D) material, the adsorption properties of the graphene-like ZnO monolayer have not been fully known. In this work, the band structures and electronic properties of NO2 molecule adsorbed onto defective ZnO monolayer are investigated by using Density Functional Theory (DFT). Firstly, the geometry structure of ZnO are optimized to obtain the most stable adsorption configuration. Then, the adsorption energy, band structure spectrum, electronic structure, charge transfer and magnetism are calculated. Finally, in order to further understand the interaction between NO2 molecule and ZnO monolayer, the total density of states (TDOS) and the partial density of states (PDOS) of ZnO monolayer before and after NO2 adsorption are investigated. The results imply that the electronic properties of the ZnO monolayer can be effectively tuned by absorbing NO2. Based on calculation results, adsorption mechanism is proposed.