Adsorption and desorption of thermally generated hydrogen atoms on Au(111) and Ag/Au(111)

Dah An Luh, Kun Rong Li, Ren Yu Huang, Ching Hung Chen, Cheng Maw Cheng, Ku Ding Tsuei, Chia Hsin Wang, Yaw Wen Yang

Research output: Contribution to journalArticlepeer-review

Abstract

To explore the possibility of employing thermally generated H atoms to determine the chemical composition of a metallic surface, we investigated the adsorption and desorption of H atoms generated with a thermal cracker on surfaces Au(111) and Ag/Au(111). Angle-resolved photoemission spectra showed that the noble-metallic surfaces deteriorated upon exposure to a flux of H atoms at ~ 100 K. Upon subsequent annealing, the order of the surfaces was mostly recovered when H atoms on the surfaces desorbed, but the recovery was incomplete even with annealing at a temperature much higher than that at which H atoms desorb. X-ray photoemission spectra showed that O-containing contaminants existed on the surfaces after the H dosing. The evolution of O 1s during annealing indicated that the O-containing contaminants were H2O and its moieties generated during thermal cracking; the disturbances of the surfaces remaining above the desorption temperature of H atoms were likely caused by chemisorbed O. Our results show that it is possible to employ thermally generated H atoms to determine the chemical composition of a metallic surface, but a small proportion of H2O in a H2 gas line might be unavoidable; precautions against possible O contamination are required when a thermal cracker is employed.

Original languageEnglish
Pages (from-to)11-18
Number of pages8
JournalSurface Science
Volume635
DOIs
StatePublished - May 2015

Keywords

  • Ag(111)
  • Angle-resolved photoemission spectroscopy
  • Au(111)
  • Hydrogen adsorption and desorption
  • Metallic surfaces
  • X-ray photoemission spectroscopy

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