Adsorption Behavior of Ni-Doped ZnO Monolayer upon SF Decomposed Components and Effect of the Applied Electric Field.

In this article, Ni-doped ZnO (Ni-ZnO) monolayer is proposed as a potential sensing material for detection of two SF decomposed components (namely, SO and SOF), based on the density functional theory (DFT) method, to monitor the operation status of SF insulation devices in the power system. The Ni-doping effect on the physicochemical properties of the pure ZnO monolayer is first studied, with the binding energy ( ) calculated as -1.49 eV. Then, the adsorption of a Ni-ZnO monolayer upon SO and SOF molecules shows that the Ni-ZnO monolayer exhibits strong chemisorption upon the two gas species, with the adsorption energy ( ) obtained as -2.38 and -2.19 eV, respectively. The electronic properties of the Ni-ZnO monolayer upon gas adsorption are studied through the density-of-state (DOS) analysis, whereas the band structure (BS) and work function (WF) analysis provide the sensing mechanism of the Ni-ZnO monolayer upon two gases. In addition, the charge-transfer behavior during adsorption in the applied electric fields is analyzed to expound the possibility of Ni-ZnO monolayer as a field-effect-transistor gas sensor. Our calculations can stimulate the study on adsorption and sensing behaviors of TM-ZnO monolayers for their applications in many fields.