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.