Microkinetic analysis of the oxygen–silver system

A microkinetic model for the oxygen–silver system has been developed, which contains thermodynamics and kinetics of molecular and dissociative chemisorption. The model parameters are extracted from UHV experiments on Ag(1 1 1) and explains molecular and dissociative sticking and desorption of molecular and atomic oxygen states on Ag(1 1 1). The model is able to bridge both the pressure and material gaps. A heat of adsorption of 126+4θO* kJ/mol O2 for atomic oxygen is predicted by the model, which compares favorable with experiments. The heat of adsorption calculated by density functional theory with some commonly used functionals is found to be very variable and generally too low for the oxygen–silver system.