A sulfur doped carbon nanotube as a potential catalyst for the oxygen reduction reaction

In this work, the catalytic effect of a sulfur doped carbon nanotube (SCNT) in a four-electron oxygen reduction reaction (ORR) was studied using theoretical methods. The structures of all reaction species, intermediates and their related transition states via possible mechanistic pathways were optimized and their energies were extracted to obtain the energy profile of the whole process. The results showed the high efficiency of SCNT (and to a lesser extent, CNT) as a catalyst of this process and SCNT could catalyze this process from the beginning to the end by releasing 15.22 eV energy. In addition, each individual step was energetically favorable and during the reaction progress, the energies of intermediates were decreased constantly. Because of the special properties of the sulfur atom, the doping of sulfur atoms into the CNT structure, make it a more useful candidate than CNT to catalyze chemical processes.