Chemical reactivity of oxygen vacancies on the MgO surface: Reactions with CO2, NO2 and metals

✍ Scribed by Elizabeth Florez; Patricio Fuentealba; Fanor Mondragón

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 710 KB
• Volume: 133-135
• Category: Article
• ISSN: 0920-5861
• DOI: 10.1016/j.cattod.2007.12.087

✦ Synopsis

Density functional theory was used to investigate the chemical reactivity of oxygen vacancies on the MgO surface towards CO 2 , NO 2 and metal atoms. The oxygen vacancies induce changes in the electronic structure of the MgO compared to that of the regular surface. The most common surface defects can have one or two electrons confined in the vacancy. The main effect of the vacancies is the reduction in the energy of the gap between the HOMO and LUMO of the MgO causing in this way a change in its reactivity towards adsorbed molecules such as CO 2 and NO 2 or atoms such as Ni, Pd, Pt, Cu and Zn. It was found that F s centers are more reactive than F þ s centers. In the case of metal atoms, the level of interaction is proportional to the degree of transfer of electron density towards the incoming atom.