Active oxidation of Cu3Au(1 1 0) using hyperthermal O2 molecular beam

✍ Scribed by Michio Okada; Yuden Teraoka

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 683 KB
• Volume: 256
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2010.03.020

✦ Synopsis

Oxidation of Cu 3 Au(1 1 0) using a hyperthermal O 2 molecular beam (HOMB) was investigated by X-ray photoemission spectroscopy in conjunction with a synchrotron light source. From the incident energy dependence of the O-uptake curve, the precursor-mediated dissociative adsorption occurs, where the trapped O 2 molecule can migrate and dissociate at the lower activation-barrier sites, dominantly at thermal O 2 exposures. Dissociative adsorption of O 2 on Cu 3 Au(1 1 0) is as effective at the thermal O 2 exposure as on Cu(1 1 0). On the other hand, at the incident energies of HOMB where the direct dissociative adsorption is dominant, it was determined that the dissociative adsorption of O 2 implies a higher activation barrier and therefore less reactivity due to the Au alloying in comparison with the HOMB oxidation of Cu(1 1 0). The dissociative adsorption progresses with the Cu segregation on Cu 3 Au(1 1 0) similarly as on Cu 3 Au(1 0 0). The growth of Cu 2 O for 2 eV HOMB suggests that the diffusion of Cu atoms also contribute to the oxidation process through the open face, which makes the difference from Cu 3 Au(1 0 0).