AVS 61st International Symposium & Exhibition
    Surface Science Tuesday Sessions
       Session SS+NS-TuA

Paper SS+NS-TuA4
Interaction of D2O on the Surface Grown ZnO(0001) Nanostructures

Tuesday, November 11, 2014, 3:20 pm, Room 309

Session: Nanostructures: Growth, Reactivity and Catalysis
Presenter: Xingyi Deng, National Energy Technology Laboratory
Authors: X. Deng, National Energy Technology Laboratory
D.C. Sorescu, National Energy Technology Laboratory
J. Lee, National Energy Technology Laboratory
C. Matranga, National Energy Technology Laboratory
Correspondent: Click to Email
D2O on the ZnO nanostructures grown on Au(111) has been investigated using a combination of experimental and theoretical methods as to probe the reactivity of model ZnO catalysts at the atomic level. We performed a series of D2O temperature programmed desorption (TPD) experiments on two distinctive surfaces, one consisting of single layer Zn(0001) nanostructures, and the others consisting of mixtures of single and bilayer ZnO(0001) nanostructures. On the basis of our TPD data and in comparison with the ZnO structural characteristics, we are able to assign each D2O TPD peak to a specific site existing on the ZnO nanostructures. Specifically, desorption peaks at 150 and 200 K are assigned to sublimation of D2O multilayers and desorption of D2O adsorbed directly on the ZnO surfaces, respectively; and D2O adsorbed on the edges of either single or bilayer ZnO desorbs at a slightly higher temperature ~260 K. More importantly, we identify that D2O binds to the steps between the single and bilayer ZnO much stronger than any other sites, desorbing around 400 K. Computational modeling based on density functional theory (DFT) calculations provides detailed adsorption geometry and energetics of the D2O-ZnO(0001)/Au(111) system, further supporting our TPD assignments. Implications of our fundamental results for ZnO based catalysts will be discussed.