Pd-decorated GaN monolayer as a promising scavenger for SO2 and SOF2 in SF6 insulation equipment: A first-principles study

[Display omitted] •Pd-doping behaviors on GaN monolayer is studied.•Expound the sensing mechanism of Pd-GaN monolayer for SF6 decomposed species.•Analyze the optical property of Pd-GaN monolayer for gas adsorptions. This work proposes Pd-decorated GaN (Pd-GaN) monolayer as a potential gas sensor for SF6 decomposed species including SO2 and SOF2 using first-principles theory, in order to evaluate the operation status of the SF6 insulation devices. Results indicate that the Pd atom prefers to be decorated on the TN site of the pristine GaN monolayer with the binding energy (Eb) of −2.07 eV, giving rise to the bandgap of 1.867 eV for the Pd-GaN system. For gas adsorptions, both SO2 and SOF2 are interacted strongly with the Pd dopant, obtaining the adsorption energy (Ead) of −1.63 and −1.51 eV, respectively. The analysis of the band structure and optical property for the Pd-GaN monolayer indicate its strong potential as a resistance-type or nano-optical sensor for gas detection with higher sensitivity upon SOF2. Our calculations are helpful to expound the potential of GaN-based materials for gas sensing in many fields.