Abstract
The adsorption of O(2) on Pt(111) was studied with Density Functional Theory calculations. Various adsorbed states of O(2) were evaluated on clean and OH/H(2)O-covered Pt(111) surfaces at the solid/gas and solid/liquid interfaces. The results reveal that the adsorption of O(2) on OH/H(2)O-covered Pt(111) surface starts with the physical adsorption of O(2). Two other adsorption states are reachable from the physisorbed state, the end-on, and bridging chemisorbed O(2). Analysis of the energetics of these adsorption states shows that O(2) physically adsorbed at the OH/H(2)O-covered Pt( 111) surface is a high energy state that requires activation to transition to the end-on chemisorbed O(2) state. On the other hand, the end-on chemisorbed state can transition to the bridging chemisorbed state with only a small activation energy when a nearby Pt adsorption site is available. Frequency analysis of the physisorbed, end-on, and bridging adsorption states shows that adsorbed O(2) stretching frequencies are close to 1400, 1300, and 900 cm(-1), respectively.