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DFT Calculations of the Adsorption States of O 2 on OH/H 2 O-Covered Pt(111).

Authors :: Santana JA
Source :: Electrocatalysis (New York, N.Y.) [Electrocatalysis (N Y)] 2020 Nov; Vol. 11 (6), pp. 612-617. Date of Electronic Publication: 2020 Aug 15.
Publication Year :: 2020
Abstract: The adsorption of O <subscript>2</subscript> on Pt(111) was studied with Density Functional Theory calculations. Various adsorbed states of O <subscript>2</subscript> were evaluated on clean and OH/H <subscript>2</subscript> O-covered Pt(111) surfaces at the solid/gas and solid/liquid interfaces. The results reveal that the adsorption of O <subscript>2</subscript> on OH/H <subscript>2</subscript> O-covered Pt(111) surface starts with the physical adsorption of O <subscript>2</subscript> . Two other adsorption states are reachable from the physisorbed state, the end-on, and bridging chemisorbed O <subscript>2</subscript> . Analysis of the energetics of these adsorption states shows that O <subscript>2</subscript> physically adsorbed at the OH/H <subscript>2</subscript> O-covered Pt( 111) surface is a high energy state that requires activation to transition to the end-on chemisorbed O <subscript>2</subscript> 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 <subscript>2</subscript> stretching frequencies are close to 1400, 1300, and 900 cm <superscript>-1</superscript> , respectively.