Oxidation of the Ru(0001) surface covered by weakly bound, ultrathin silicate films

SURFACE SCIENCE

卷:646

Article

Emmez, Emre¹  Boscoboinik, J. Anibal²  Tenney, Samuel²  Sutter, Peter²  Shaikhutdinov, Shamil¹  Freund, Hans-Joachim¹ 

[1] MPG, Fritz Haber Inst, Chem Phys Abt, Faradayweg 4-6, D-14195 Berlin, Germany

[2] Brookhaven Natl Lab, Ctr Funct Nanomat, Upton, NY 11973 USA

关键词: Ultrathin oxide films;    Surface oxidation;    Ru oxide;    Passivation;   

DOI  :  10.1016/j.susc.2015.06.019

来源: Elsevier

【 摘 要 】

Bilayer silicate films grown on metal substrates are weakly bound to the metal surfaces, which allows ambient gas molecules to intercalate the oxide/metal interface. In this work, we studied the interaction of oxygen with Ru(0001) supported ultrathin silicate and aluminosilicate films at elevated 02 pressures (10(-5)-10 mbar) and temperatures (450-923 K). The results show that the silicate films stay essentially intact under these conditions, and oxygen in the film does not exchange with oxygen in the ambient. 02 molecules readily penetrate the film and dissociate on the underlying Ru surface underneath. The silicate layer does however strongly passivate the Ru surface towards RuO2(110) oxide formation that readily occurs on bare Ru(0001) under the same conditions. The results indicate considerable spatial effects for oxidation reactions on metal surfaces in the confined space at the interface. Moreover, the aluminosilicate films completely suppress the Ru oxidation, providing some rationale for using crystalline aluminosilicates in anti-corrosion coatings. (C) 2015 Elsevier B.V. All rights reserved.

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