Molecular-beam study of the adsorption and desorption of hydrogen sulfide on Ag{111}

The adsorption and desorption of hydrogen sulfide on Ag{111} has been studied with molecular-beam methods and temperature-programmed desorption. Precursor adsorption kinetics were observed for H2S on the Ag{111} at 80 K. The initial sticking probability for H2S on Ag{111} is so=0.95±0.05, below 110 K. The results showed that, at 80 K, the H2S adsorbs reversibly into a physisorbed state, which desorbs at ∼97 K. Dissociative chemisorption was not observed for H2S on the clean Ag{111} substrate at below 100 K, in contrast with results obtained on transition metals. The desorption kinetics showed marked dependence on substrate pre-treatment.