Adsorption and reaction mechanisms of SO2 on Rh(111) surface: A first-principle study

• Adsorption of reactants, intermediates, and products involved were investigated.
• The Mulliken charge and projected density of states were analyzed.
• The reactions of SO2 on Rh(111) were discussed.
• The reaction mechanism was investigated.

The adsorption and decomposition reaction mechanisms of SO2 on Rh(111) has been systematically studied using self-consistent periodic density functional theory (DFT). All possible adsorptions of reactants, intermediates, and products involved are investigated. Two stable adsorption configurations of SO2 on Rh(111) were confirmed: chair mode (η2(S)–η1(O)) and parallel mode ((η1(S)–η1(O)–η1(O)). The decomposition reaction of SO2 takes place along SO2 → SO + O → S + 2O, in which the second step is the rate-determining step. For the high energy barrier and low rate constant, the disproportionation reaction is not facile among all the possible reactions.