Carbon monoxide oxidation on a Au(111) surface modified by spontaneously deposited Ru

Abstract

The spontaneous deposition of Ru on Au(111) was performed in 10-3 M RuCl3-0.5 M H2SO4 solution. The obtained surface was characterized by STM under potential control in 0.5 M H2SO4 solution. The coverage of the Au(111) terraces by deposited Ru was estimated by STM to be 0.02 ML. Step decoration could be noticed in the STM images, which indicates that the steps, as lined defects, are active sites for the nucleation of Ru monolayer islands, while the random distribution of Ru nuclei, observed on the terraces indicates point defects as active sites. The electrocatalytic activity of Au(111) surface modified by spontaneously deposited Ru was studied towards CO oxidation. The significant enhancement in the reaction rate compared to CO oxidation on a pure Au(111) surface, indicated that the edges of the deposited Ru islands were the active sites for the reaction.

Ru je deponovan spontano na monokristalu Au(111) iz rastvora 10-3MRuCl3 + 0.5 MH2SO4. Karakterizacija dobijene površine je izvedena in situ STM-om u 0.5MH2SO4. Pokrivenost Au(111) površine deponovanim Ru na terasama je bila 0,02 ML. Na STM slikama se uočava dekoracija stepenica depozitom, što ukazuje da su stepenice, kao linijski defekti, aktivna mesta za nukelaciju ostrva Ru, dok neravnomerna raspodela ostrva Ru na terasama ukazuje na tačkaste defekte kao aktivna mesta. Ispitivana je elektrokatalitička aktivnost Au(111) površine modifikovane spontano deponovanim Ru za oksidaciju CO. Značajno povećanje brzine reakcije na Ru/Au(111) površini u poređenju sa reakcijom na čistoj Au(111) površini, ukazuje da su ivice deponovanih ostvra Ru aktivna mesta za reakciju.