First-Principles Study of Au-Doped InN Monolayer as Adsorbent and Gas Sensing Material for SF(6) Decomposed Species

As an insulating medium, sulfur hexafluoride (SF(6)) is extensively applied to electrical insulation equipment to ensure its normal operation. However, both partial discharge and overheating may cause SF(6) to decompose, and then the insulation strength of electrical equipment will be reduced. The adsorption properties and sensing mechanisms of four SF(6) decomposed components (HF, SO(2), SOF(2) and SO(2)F(2)) upon an Au-modified InN (Au-InN) monolayer were studied in this work based on first-principles theory. Meanwhile, the adsorption energy (E(ad)), charge transfer (Q(T)), deformation charge density (DCD), density of states (DOS), frontier molecular orbital and recovery property were calculated. It can be observed that the structures of the SO(2), SOF(2) and SO(2)F(2) molecules changed significantly after being adsorbed. Meanwhile, the E(ad) and Q(T) of these three adsorption systems are relatively large, while that of the HF adsorption system is the opposite. These phenomena indicate that Au-InN monolayer has strong adsorption capacity for SO(2), SOF(2) and SO(2)F(2), and the adsorption can be identified as chemisorption. In addition, through the analysis of frontier molecular orbital, it is found that the conductivity of Au-InN changed significantly after adsorbing SO(2), SOF(2) and SO(2)F(2). Combined with the analysis of the recovery properties, since the recovery time of SO(2) and SO(2)F(2) removal from Au-InN monolayer is still very long at 418 K, Au-InN is more suitable as a scavenger for these two gases rather than as a gas sensor. Since the recovery time of the SOF(2) adsorption system is short at 418 K, and the conductivity of the system before and after adsorption changes significantly, Au-InN is an ideal SOF(2) gas-sensing material. These results show that Au-InN has broad application prospects as an SO(2), SOF(2) and SO(2)F(2) scavenger and as a resistive SOF(2) sensor, which is of extraordinary meaning to ensure the safe operation of power systems. Our calculations can offer a theoretical basis for further exploration of gas adsorbent and resistive sensors prepared by Au-InN.