Hydrogen cyanide sensor based on the porphyrin-like B₄-doped [60]-fullerenes: a DFT study

Using density functional theory calculations, a porous C₆₀ fullerene with B₄ porphyrin-like cavity (C₅₄B₄) is designed, and its potential application is investigated in the HCN detection. The formation energy is predicted to be about − 155.5 kcal/mol, which is comparable with that of C₅₄N₄ nanocage (~ − 156.1 kcal/mol) and is somewhat less negative than that of [60] fullerene (~ − 161.0 kcal/mol). The C₅₄B₄ nanocage shows much higher electrical conductivity compared to the C₆₀ and C₅₄N₄ nanocages. We found that the HCN adsorbs on the C₅₄B₄ nanocage via two different mechanisms, including vertical adsorption from its N-head and horizontal adsorption with N–C bond. These mechanisms differently affect the electronic properties of C₅₄B₄. The most stable HCN/C₅₄B₄ complex is that in which the HCN molecule lies on the center of B₄ cavity so that each C or N atom is in connection with two B atoms with adsorption energy of about − 73.5 kcal/mol. Upon the HCN adsorption, a large charge transfer about 0.33 e and a great gap opening about 1.56 eV occurred for C₅₄B₄, which sharply increases the electrical resistance of C₅₄B₄, but its effect on work function is negligible. Thus, we concluded that C₅₄B₄ may be a promising electronic sensor for the HCN gas.