H₂S adsorption on pristine and metal-decorated (8, 0) SWCNT: a first principle study

Adsorption of hydrogen sulfide (H₂S) on the surface of catalytic systems containing (8, 0) single-walled carbon nanotube decorated with Ni and Pd transition metals was investigated using plane-wave density functional theory. SWCNT was modified by adding Ni and Pd atoms to both inside and outside the nanotube and replacing carbon atoms with these metals. All structures were relaxed, and their structural and electronic properties were investigated before and after H₂S adsorption and compared with pristine (8, 0) SWCNT properties. Obtained results showed that decorating CNTs with metals increases CNT efficiency for H₂S adsorption. The most negative adsorption energies were observed when H₂S was adsorbed on the surfaces of metal-decorated nanotube. Electronic properties like band structures and density of states indicated that systems containing Ni on SWCNT are more effective at adsorbing and sensing H₂S molecules. Hydrogen sulfide adsorption also changed the magnetization of Ni-decorated structures. Moreover, adsorption of H₂S from H side to Ni-decorated SWCNT leads to dissociation of H₂S to HS and S atom. Obtained results showed that metal-decorated nanotubes are potentially good candidates for separating H₂S from industrial waste gas streams and for its use in H₂S sensors.