AVS 62nd International Symposium & Exhibition
    Surface Science Wednesday Sessions
       Session SS+AS+NS-WeM

Paper SS+AS+NS-WeM11
Enhanced Adsorption of CO2 at Steps of Planar ZnO(0001) Grown on Au(111)

Wednesday, October 21, 2015, 11:20 am, Room 113

Session: Metals, Alloys & Oxides: Reactivity and Catalysis
Presenter: Xingyi Deng, National Energy Technology Laboratory
Authors: X. Deng, National Energy Technology Laboratory
D. Sorescu, National Energy Technology Laboratory
J. Lee, National Energy Technology Laboratory
Correspondent: Click to Email
In this work, we study the energetics of CO2 adsorbed on the bi- and tri-layer ZnO(0001) grown on Au(111) using temperature programmed desorption (TPD) and calculations based on density functional theory (DFT). Both bi- and tri-layer ZnO(0001) on Au(111) adopt a planar, graphite-like structure via an inter-layer relaxation to minimize the surface dipole arising from alternating Zn2+ and O2- layers. CO2 is adsorbed weakly on these planar ZnO(0001) surfaces, desorbing between 125-130 K in TPD. Two other desorption peaks were also observed in TPD at ~ 150 and 280-320 K and are attributed to the CO2 adsorption at the steps between the bi- and tri-layer ZnO(0001) surfaces. This enhanced adsorption of CO2 at the steps is supported by DFT calculations: the computed energetics of CO2 adsorbed on surfaces and at steps is indeed consistent with that estimated from the TPD experiments via the Redhead method. Implications of our fundamental results for ZnO based catalysts will be discussed.