Abstract
The adsorption of cyanogen (C
2
N
2
) was explored onto pure, Cu-doped, and Al-doped graphynes through density functional theory calculations. C
2
N
2
gas is weakly adsorbed on the pure graphyne with adsorption energy of 11.0 kcal/mol and the electronic properties of the pure graphyne do not change significantly. Cu-doping improves the performance of the graphyne and makes it more reactive and sensitive to C
2
N
2
, which may be a good choice for the production of C
2
N
2
chemical sensors. According to the calculations, the C
2
N
2
adsorption reduces HOMO/LUMO gap (E
g
) of the Cu-doped sheet from 2.42 to 1.52 eV (∼−37%), which can be concluded that the electrical conductivity of the nanosheet has increased. Thus, the Cu-doped graphyne can generate electrical signals when the C
2
N
2
molecules approach. By Al-doping the E
g
of graphyne reduces by about 17.8% after C
2
N
2
adsorption which is very small compared to the Cu-doping.