The interaction of size-selected Ru₃ clusters with RF-deposited TiO₂: probing Ru–CO binding sites with CO-temperature programmed desorption

Abstract

A loss of Ru–CO sites on the clusters suggests encapsulation.

Encapsulation of Size-Selected Ru3 Clusters into RF-Deposited TiO2

“…An HHV/Edwards TF500 Sputter Coater was used at a pressure of <2 x 10 -5 mbar. This process has been described in detail in previous publications [30,58]. Based on SEM measurements performed on previously prepared wafers, the thickness of the RF-TiO2 was approximately 150 nm [58], which is thick enough that the SiO2 wafer beneath would not affect any measured electron spectra.…”

“…CVD-deposited samples are referred to as CVD-Ru3(CO)12. At Flinders University, the CVD procedure followed the method described in the Supplementary Material (page 2), which has also been described in previous work [30]. Briefly, Ru3(CO)12 was inserted into a loading chamber and allowed to evaporate/deposit onto samples; 120 minutes for RF-TiO2 and 30 minutes for TiO2 (110).…”

“…CS depositions were performed in situ by a laser vaporisation CS which has been used in several previous works [30,75,76,78] onto both RF-TiO2 and SiO2. The instrument details and standard deposition procedure are given in the Supplementary Material (pages 2-3).…”

“…The latter can be deposited onto surfaces in two different ways: solution deposition (here shortened to SD, also called solution submersion) [18] and chemical vapor deposition (CVD) [19][20][21][22][23][24][25][26][27][28][29]. The deposition method can affect the resultant cluster properties, however very few studies have directly compared the cluster properties of identically sized clusters resulting from different deposition methods [21,30].…”

“…In our previous study, CO temperature programmed desorption (CO-TPD) was performed on Ru3 clusters deposited by CVD (Ru3(CO)12) and CS (bare Ru3) onto RF-TiO2 [30]. This involved dosing 13 CO onto the samples under UHV, then heating while monitoring the desorbing gas molecules.…”