Adsorption behaviors, electronic and gas-sensing properties of C3N4 monolayers and heterojunctions for SF6 decomposition products

We investigated systematically adsorption behaviors, electronic and gas-sensing properties of SF6 decomposed gases, i.e., H2S, SO2, HF, SOF2 and SO2F2, on the C3N4 monolayers and heterojunctions via first-principles methods. The pure C3N4 monolayer was predicted to be reusable gas sensors for H2S detection with high sensitivity at room temperature in a dry environment. We further found two stable configurations of the C3N4/graphene heterojunctions, (simply as R-C3N4/graphene and T-C3N4/graphene). Their stabilities were confirmed by lattice mismatch, binding energy and MD simulations, and both of them can be distinguished via their different optical properties. Finally, we found that the T-C3N4/graphene heterojunction has little sensitivity to SF6 decomposed species, which indicates that the T-C3N4/graphene heterojunction is unaccommodated for SF6 decomposed gas sensor, however, the R-C3N4/graphene heterojunction could be viewed as a promising gas sensor towards H2S, SOF2, and SO2F2, whether the humidity exists or not.