How to Avoid the Oxidation of Silicene/Ag(111)? Reaction Mechanisms of O 2 with Chlorinated Silicene

SORIA, FEDERICO A.; PATRITO, EDUARDO M.

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Año: 2020 vol. 124 p. 7327 - 7327

1932-7447

b initio atomistic thermodynamics and ab initio molecular dynamics simulations were performed to investigate the reaction of O2 with hydrogenated and chlorinated silicene supported on Ag(111) to evaluate the passivating capacity of chlorine-functionalized silicene. The phase diagram of silicene supported on Ag(111) is dominated by the chlorinated 1 × 1?silicene phase in a wide range of Cl2 and H2 pressures. From a thermodynamic point of view, the oxidation of silicene is rather insensitive to the type of functionalization and is very exothermic. However, the kinetics of the reactions are very different for both functionalizations. The O2 molecules readily react with hydrogenated silicene to yield the surface Si?OH groups as well as Si?O?Si moieties upon the insertion of O atoms into Si?Si bonds. On the contrary, chlorinated silicene has a low reactivity toward O2 because of large steric effects during the penetration of O2 through the layer of chlorine atoms. Halogenation of silicene