The MgO(111) versus MgO(100) supported Au ultrasmall particles as a model catalyst for carbon monoxide oxidation

• Published in: Solid state communications 2018-08, Vol.276, p.28-32
• Main Authors: Grigorkina, G.S., Zaalishvili, V.B., Burdzieva, O.G., Fukutani, K., Magkoev, T.T.
• Format: Article
• Language: English
• Subjects: A. Carbon monoxide and oxygen; A. Magnesium oxide and gold; B. Adsorption and reaction; E. Surface analysis techniques
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2018.04.001

Adsorption and reaction of carbon monoxide and oxygen on gold ultrasmall particles deposited on MgO(111) and MgO(100) films in ultra-high vacuum have been studied by surface sensitive spectroscopic and structural techniques. The 3 nm thick MgO(111) and MgO(100) films were formed on Mo(110) and Mo(100) supports, respectively, as templates to grow the corresponding oxide structures. It is found that, unlike MgO(100), and many other oxide surfaces, reported in the literature, the Au particles of and average size of c.a. 2–3 nm, deposited on MgO(111), acquire an effective positive charge as a result of charge transfer from the metal as an effect stabilizing the uncompensated dipolar moment of the polar substrate. Gold nanoparticles on both MgO(111) and MgO(100) are active model catalysts for carbon monoxide oxidation by oxygen, as revealed by temperature desorption studies. However the effect of MgO(111) support is markedly more pronounced due to stronger interaction of precursor CO and O2 induced by specific state of supported Au ultrasmall particles. •MgO(111) film of thickness up to 3 nm can be formed on Mo(110) by thermal deposition.•Gold particles with size up to 3 nm, deposited on MgO(111), acquire positive charge.•Stretch frequency of CO adsorbed on Au/Mg(111) is blue-shifted compared to Au/Mg(100).•Oxygen dissociatively adsorbs on Au ultrasmall particles deposited on MgO(111).•The CO adsorbed on Au/MgO(111) converts to CO2 in an oxygen ambient upon heating.