In situ observation of H2 dissociation on the ZnO (0001) surface under high pressure of hydrogen using ambient-pressure XPS |
| |
| Authors: | Bongjin S Mun Zhi Liu Md Abdul Motin Probir C Roy Chang Min Kim |
| |
| Affiliation: | 1. Department of Physics and Photon Sciences, Gwangju Institute of Science and Technology, Gwangju, 500-712, South Korea;2. State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, People''s Republic of China;3. School of Physical Science and Technology, Shanghai Tech University, Shanghai 200031, People''s Republic of China;4. Department of Chemistry, Kyungpook National University, Daegu, 41566, South Korea |
| |
| Abstract: | The interaction of H2 molecules with a ZnO (0001) single crystal surface has been studied over a wide pressure (10?6–0.25 Torr) and temperature (300–600 K) range using ambient pressure X-ray photoelectron spectroscopy (AP-XPS). ZnO is well-known for interstitial hydrogen and hydrogen atoms in ZnO are believed to be incorporated by the dissociative adsorption of H2 molecules in the atmosphere and their subsequent diffusion into the bulk. The dissociative adsorption of H2 has been investigated at elevated pressures because H2 molecules are not dissociated on the ZnO single crystal surface under ultrahigh vacuum (UHV) conditions. When the pressure is increased to several mTorr, the dissociative adsorption of H2 takes place to form OH bonds on the surface. At 0.25 Torr, the ZnO surface is saturated with H atoms and the coverage is estimated to be 1.1 × 1015 atoms/cm2 at 300 K. At higher surface temperatures, the equilibrium between the dissociative adsorption of gas-phase H2 molecules and the associative desorption of surface H atoms is established. While maintaining the equilibrium, the surface has been monitored successfully in situ by utilizing AP-XPS. |
| |
| Keywords: | Hydrogen ZnO Surface AP-XPS TPD Pressure-gap |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
