AVS 66th International Symposium & Exhibition
    Fundamental Discoveries in Heterogeneous Catalysis Focus Topic Thursday Sessions
       Session HC+2D+SS-ThM

Paper HC+2D+SS-ThM6
Structural and Chemical Effects of Cesium on the Cu(111) and CuxO/Cu(111) Surface

Thursday, October 24, 2019, 9:40 am, Room A213

Session: Nanoscale Surface Structure in Heterogeneously-Catalyzed Reactions
Presenter: Rebecca Hamlyn, Stony Brook University
Authors: R. Hamlyn, Stony Brook University
M. Mahapatra, Brookhaven National Laboratory
I. Orozco, Stony Brook University
M.G. White, Brookhaven National Laboratory
S. Senanayake, Brookhaven National Laboratory
J.A. Rodriguez, Brookhaven National Laboratory
Correspondent: Click to Email
Surface additives, particularly those of alkali metals, are commonly used for promotion of catalytic processes. These processes include carbon oxide reactions such as the water-gas shift and methanol synthesis over Cu-based catalysts. Both reactions are known to be promoted by Cs doping. Partially oxidized Cu is also understood to have a critical role in the activity of the aforementioned processes, as strictly metallic copper will not survive under redox conditions. In an effort to better understand how small additions of alkalis such as Cs act as promoters, we have carried out model studies of cesium over a metallic and oxidized copper surface using scanning tunneling microscopy and x-ray photoelectron spectroscopy. We find that the oxide structure assists in anchoring Cs over the weaker electrostatic interactions with the bare copper surface, allowing for room temperature imaging. Furthermore, with higher coverages or elevated temperature, cesium induces formation of a new ordered structure. This work provides a molecular-scale understanding of the cesiated surface, and serves as a basis for insight toward its mechanism of action in conversion of relevant gases (H2O, CO, CO2).