Gas sensing properties of Mg-doped graphene for H2S, SO2, SOF2 and SO2F2
based on DFT
Abstract
Sulfur hexafluoride decompositions have been studied to analyze their
adsorption properties on pristine graphene (PG) and Mg-doped graphene
(MgG). First of all, after calculating the formation energy of three Mg
doping sites, the T doping site of Mg-doped graphene is the most stable
one. Then, several characteristic structures with different orientations
and positions of the gas molecules have been used to adsorb on PG and
MgG, respectively. By calculating the adsorption energies and distance,
the most stable adsorption structure of each gas molecule is obtained.
In addition, charge transfer (Qt), the density of states (DOS)
distribution, the energy of highest occupied molecular orbital (HOMO)
and lowest unoccupied molecular orbital (LUMO) were used to further
analyze the conductivity change and chemical stability of each
adsorption system. The results indicate that the adsorption interactions
of H2S, SO2, SOF2 and SO2F2 on PG are weak. H2S adsorbed on MgG
presented physical adsorption, while the adsorption behaviors of SO2,
SOF2 and SO2F2 on MgG are chemisorption. And the adsorption strength was
SO2F2 > SOF2 > SO2. In short, MgG shows better
selectivity and higher sensitivity to SO2, SOF2 and SO2F2 than PG,
demonstrating that the MgG material can be used as suitable gas sensing
equipment based on SF6 decomposition products detection, which provides
a meaningful guide of alkaline earth metal doped graphene in the
detection of partial discharge and partial overheat in gas-insulated
switchgears (GIS).