Theoretical Study of the Gas Sensing Mechanism of N3&Ni Doped Double Vacancies Defect Graphene Upon SF6 Decompositions

It is an important way by detecting SF
₆
decomposition products to evaluate the insulation condition of SF
₆
insulated power equipment. In this paper, N
₃
&Ni doped 555-777graphene (N
₃
&Ni-graphene) is proposed as a new gas sensor to detect the characteristic components of SF
₆
decomposition products: H
₂
S, SO
₂
, SOF
₂
and SO
₂
F
₂
. In order to get insights into the gas sensing mechanism, the geometry structures, electron structures and conductivity are analyzed by simulation method based on density functional theory. The calculation results show that N
₃
&Ni dopant can improve the conductivity and surface activity of 555-777 graphene. Specifically, H
₂
S and SO
₂
absorbing on N
₃
&Ni-graphene surface will increase the conductivity obviously, while the other two kinds of gas molecules will decrease the conductivity. The sensitivity of H
₂
S is greater than SO
₂
according to the changed value of energy gap. It is also indicated that N
₃
&Ni-graphene can absorb the above four characteristic components stably with high adsorption energies, complex orbital hybridizations and multi-level charge transfer. This work will provide some theoretical guidance to develop a novel gas sensor to evaluate the insulation condition of SF
₆
insulated equipment.