Eco-friendly designing of zinc oxide nanoparticle as a potential semiconducting device for H2O-capture: a density functional theory study

Abstract

We employ first-principles calculations to investigate the structural stability and electronic properties of zinc oxide (ZnO) nanocluster adsorbed with H₂O molecule. A comprehensive investigation on H₂O grabbing by ZnO nanocluster was carried out using DFT computations at the CAM–B3LYP–D3/6–311+G (d, p) level of theory. The hypothesis of the energy adsorption phenomenon was confirmed by density distributions of CDD, TDOS/PDOS/OPDOS, and ELF for ZnO and ZnO–H₂O. A vaster jointed area engaged by an isosurface map for H/OH adsorption on ZnO surface towards formation of ZnO–H₂O complex due to labeling atoms of O1, Zn15, O27, H29, H30. Therefore, it can be considered that zinc in the functionalized ZnO might have more impressive sensitivity for accepting the electrons in the process of H/OH adsorption. It is considerable that when all surface atoms of ZnO are coated by OH and H groups, the semiconducting behavior is recovered. Our results open up the possibility of tailoring the electronic properties by controlling the surface adsorption sites. The nanoclusters of bare ZnO and ZnO–H₂O can be defined by ELF graphs owing to exploring their delocalization/localization characterizations of electrons and chemical bonds. The results indicate that the stability and the optical gap are related to the sizes and symmetries of the clusters. Further, it is shown that the structures have much greater impact on the optical gap, there is the dipole-forbidden transition in the optical gap for high symmetric structures.