AVS 65th International Symposium & Exhibition
    Surface Science Division Friday Sessions
       Session SS+AS+HC-FrM

Paper SS+AS+HC-FrM4
Surface Hydroxylation of Polar (000-1) and Non-polar (11-20) ZnO Probed with AP-XPS

Friday, October 26, 2018, 9:20 am, Room 203C

Session: Near/Ambient Pressure and Bridging Gaps between Surface Science and Catalysis
Presenter: Sana Rani, University of Delaware
Authors: S. Rani, University of Delaware
A. Broderick, University of Delaware
J.T. Newberg, University of Delaware
Correspondent: Click to Email
The interaction of ZnO with water vapor has been an important topic of research due to the relevance for numerous catalytic processes including water-gas shift reaction, methanol synthesis, olefin hydrogenation, and gas sensor applications. ZnO based humidity nanosensors were found to have high sensitivity towards humidity and fast response time in heterogeneous catalysis. The presence of water strongly modifies the surface properties depending on the substrate and coverage. The adsorbed water can catalyze heterogeneous reactions and corrosion by proton transfer and solvating products. Dissociation of adsorbed water is of particular interest for catalysis, as this may be the first step in the activation of water molecules for chemical reactions. In this work, surface thermodynamic calculations were applied to synchrotron based ambient pressure X-ray photoelectron spectroscopy (AP-XPS) data to investigate the interface between water vapor and the low index polar (000-1) and non-polar (11-20) ZnO surfaces. Three isobaric experiments were performed over a range of temperatures from 10 to 500°C. It is hypothesized that observed hydroxyl groups, adsorbed water and carbonates on the ZnO surface can significantly influence heterogeneous catalytic reactions under ambient conditions.