AVS 62nd International Symposium & Exhibition
    In-Situ Spectroscopy and Microscopy Focus Topic Wednesday Sessions
       Session IS+SS+NS+BI+VT+MN+AS-WeA

Paper IS+SS+NS+BI+VT+MN+AS-WeA12
In Situ STM Observation of Pd(110) Under the Hydrogen Pressure Between 10-6 Pa and 10-3 Pa

Wednesday, October 21, 2015, 6:00 pm, Room 211B

Session: In situ Imaging of Liquids using Microfluidics
Presenter: Jun Yoshinobu, University of Tokyo, Japan
Authors: J. Yoshinobu, University of Tokyo, Japan
H. Kikuchi, University of Tokyo, Japan
T. Koitaya, University of Tokyo, Japan
K. Mukai, University of Tokyo, Japan
S. Yoshiomoto, University of Tokyo, Japan
Correspondent: Click to Email
Hydrogen adsorption and absorption on/in Pd and Pd alloys are vital processes for the hydrogen storage and hydrogen permeation materials. We investigated the Pd(110) surface under the hydrogen pressures between 10-6 Pa and 10-3 Pa at room temperature using in-situ atom-resolved scanning tunneling microscopy (STM). We observed missing-atom, missing-row and added-row structures and the number of atoms in these structures were quantitatively analyzed as a function of exposure time. Note that adatoms were not detected probably because they were mobile in the present experimental conditions. At 10-6 Pa, the numbers of missing-row and added-row atoms increased up to ~20 L (langmuir) and after that they were gradually reaching the saturation (steady-state). On the other hand, the number of missing-atoms decreased gradually from the initial stage. With increasing the hydrogen pressures the number of missing-row atoms and added-row atoms increased, and the whole surface was covered with these reconstructed structures after large exposures (>1000 L). It has been known that not only hydrogen adsorption but also hydrogen absorption occur in such conditions. Thus, the missing-row and added-row reconstructed structures are inevitable for hydrogen absorption on Pd(110).