TY  - JOUR
AU  - Štrbac, Svetlana
AU  - Johnston, Christina Marie
AU  - Lu, Guoqiang
AU  - Crown, Alechia
AU  - Wiȩckowski, Andrzej
PY  - 2004
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4342
AB  - We provide an overview of structure and reactivity of selected bimetallic single crystal electrodes obtained by the method of spontaneous deposition. The surfaces that are described and compared are the following: Au(111)/Ru, Pt(111)/Ru and Pt(111)/Os. Detailed morphological information is presented and the significance of this work in current and further study of nanoisland covered surfaces in the catalytic and spectroscopic perspective is highlighted. All surfaces were investigated by in situ STM and by electroanalytical techniques. The results confirm our previous data that nanosized Ru islands are formed with specific and distinctive structural features, and that the Ru growth pattern is different for Au(111) and Pt(111). For Au(111), Ru is preferentially deposited on steps, while a random and relatively sparse distribution of Ru islands is observed on terraces. In contrast, for Ru deposited on Pt(111), a homogeneous deposition over all the Pt(111) surface was,found. Os is also deposited homogeneously, and at a much higher rate than Ru, and even within a single deposition it forms a large proportion of multilayer islands. On Au(111), the Ru islands on both steps and terraces reach the saturation coverage within a short deposition time, and the Ru islands grow to multilayer heights and assume hexagonal shapes. On Pt(111), the Ru saturation coverage is reached relatively fast, but when a single deposition is applied, Ru nanoislands of mainly monoatomic height are formed, with the Ru coverage not exceeding 0.2 ML. For Ru deposits on Pt(111), we demonstrate that larger and multilayer islands obtained in two consecutive depositions can be reduced in size-both in height and width-by oxidizing the Ru islands and then by reducing them back to a metallic state. A clear increase in the Ru island dispersion is then obtained. However, methanol oxidation chronoamperometry shows that the surface with such a higher dispersion is less active to methanol oxidation than the initial surface. A preliminary interpretation of this effect is provided. Finally, we studied CO stripping reaction on Pt(111)/Ru, Au(111)/Ru and on Pt(111)/Os. We relate CO oxidation differences observed between Pt(111)/Ru and Pt(111)/Os to the difference in the oxophilicity of the two admetals. In turn, the difference in the CO stripping reaction on Pt(111)/Ru and Au(111)/Ru with respect to the Ru islands is linked to the effect of the substrate on the bond strength and/or adlayer structure of CO and OHads species.
PB  - Elsevier
T2  - Surface Science
T1  - In situ STM study of nanosized Ru and Os islands spontaneously deposited on Pt(111) and Au(111) electrodes
VL  - 573
VL  - 99
IS  - 1
SP  - 80
DO  - 10.1016/j.susc.2004.04.060
ER  - 

@article{
author = "Štrbac, Svetlana and Johnston, Christina Marie and Lu, Guoqiang and Crown, Alechia and Wiȩckowski, Andrzej",
year = "2004",
abstract = "We provide an overview of structure and reactivity of selected bimetallic single crystal electrodes obtained by the method of spontaneous deposition. The surfaces that are described and compared are the following: Au(111)/Ru, Pt(111)/Ru and Pt(111)/Os. Detailed morphological information is presented and the significance of this work in current and further study of nanoisland covered surfaces in the catalytic and spectroscopic perspective is highlighted. All surfaces were investigated by in situ STM and by electroanalytical techniques. The results confirm our previous data that nanosized Ru islands are formed with specific and distinctive structural features, and that the Ru growth pattern is different for Au(111) and Pt(111). For Au(111), Ru is preferentially deposited on steps, while a random and relatively sparse distribution of Ru islands is observed on terraces. In contrast, for Ru deposited on Pt(111), a homogeneous deposition over all the Pt(111) surface was,found. Os is also deposited homogeneously, and at a much higher rate than Ru, and even within a single deposition it forms a large proportion of multilayer islands. On Au(111), the Ru islands on both steps and terraces reach the saturation coverage within a short deposition time, and the Ru islands grow to multilayer heights and assume hexagonal shapes. On Pt(111), the Ru saturation coverage is reached relatively fast, but when a single deposition is applied, Ru nanoislands of mainly monoatomic height are formed, with the Ru coverage not exceeding 0.2 ML. For Ru deposits on Pt(111), we demonstrate that larger and multilayer islands obtained in two consecutive depositions can be reduced in size-both in height and width-by oxidizing the Ru islands and then by reducing them back to a metallic state. A clear increase in the Ru island dispersion is then obtained. However, methanol oxidation chronoamperometry shows that the surface with such a higher dispersion is less active to methanol oxidation than the initial surface. A preliminary interpretation of this effect is provided. Finally, we studied CO stripping reaction on Pt(111)/Ru, Au(111)/Ru and on Pt(111)/Os. We relate CO oxidation differences observed between Pt(111)/Ru and Pt(111)/Os to the difference in the oxophilicity of the two admetals. In turn, the difference in the CO stripping reaction on Pt(111)/Ru and Au(111)/Ru with respect to the Ru islands is linked to the effect of the substrate on the bond strength and/or adlayer structure of CO and OHads species.",
publisher = "Elsevier",
journal = "Surface Science",
title = "In situ STM study of nanosized Ru and Os islands spontaneously deposited on Pt(111) and Au(111) electrodes",
volume = "573, 99",
number = "1",
pages = "80",
doi = "10.1016/j.susc.2004.04.060"
}

Štrbac, S., Johnston, C. M., Lu, G., Crown, A.,& Wiȩckowski, A.. (2004). In situ STM study of nanosized Ru and Os islands spontaneously deposited on Pt(111) and Au(111) electrodes. in Surface Science
Elsevier., 573(1), 80.
https://doi.org/10.1016/j.susc.2004.04.060

Štrbac S, Johnston CM, Lu G, Crown A, Wiȩckowski A. In situ STM study of nanosized Ru and Os islands spontaneously deposited on Pt(111) and Au(111) electrodes. in Surface Science. 2004;573(1):80.
doi:10.1016/j.susc.2004.04.060 .

Štrbac, Svetlana, Johnston, Christina Marie, Lu, Guoqiang, Crown, Alechia, Wiȩckowski, Andrzej, "In situ STM study of nanosized Ru and Os islands spontaneously deposited on Pt(111) and Au(111) electrodes" in Surface Science, 573, no. 1 (2004):80,
https://doi.org/10.1016/j.susc.2004.04.060 . .

TY  - JOUR
AU  - Štrbac, Svetlana
AU  - Behm, Rolf Jürgen
AU  - Crown, Alechia
AU  - Wiȩckowski, Andrzej
PY  - 2002
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4340
AB  - Spontaneous deposition of ruthenium on Au(1 1 1) surfaces from 1.0 mM RuCl3 + 0.5 M H2SO4 (or 0.1 M HClO4) solutions was investigated by in situ STM and cyclic voltammetry, focusing on the morphology of the resulting submonolayer Ru modified surfaces. STM results show a pronounced step decoration, indicating that the steps are active sites for the nucleation of Ru monolayer islands, while a random distribution of Ru nuclei is observed on terraces. During deposition, the open circuit potential rapidly increases from 0.38 to above 0.72 V vs. (Ag/AgCl). Experiments with different deposition times show that deposition from sulfuric acid solution saturates after 3 min deposition, the island size reaches its saturation value of 2.8 nm after 1 min. Significantly higher deposition activities and saturation coverages are found for deposition from perchlorate solution and for deposition on highly stepped surfaces/surface areas, indicative of a pronounced anion effect and reflecting the higher activity of steps for Ru deposition, respectively. In both cases, in particular for deposition in perchlorate solution, islands grow to multilayer heights and assume hexagonal shapes. Finally it is shown that multiple deposition can be utilized to reach higher coverages, attaining step saturation also in sulfuric acid solution. The Ru modified Au(1 1 1) electrode was found to be inert for hydrogen adsorption, and the electrochemical results indicate that the ruthenium islands inhibit long-range ordering of the sulfate adlayer on the substrate.
PB  - Elsevier
T2  - Surface Science
T1  - In situ STM imaging of spontaneously deposited ruthenium on Au(111)
VL  - 517
IS  - 1-3
SP  - 207
EP  - 218
DO  - 10.1016/S0039-6028(02)02062-9
ER  - 

@article{
author = "Štrbac, Svetlana and Behm, Rolf Jürgen and Crown, Alechia and Wiȩckowski, Andrzej",
year = "2002",
abstract = "Spontaneous deposition of ruthenium on Au(1 1 1) surfaces from 1.0 mM RuCl3 + 0.5 M H2SO4 (or 0.1 M HClO4) solutions was investigated by in situ STM and cyclic voltammetry, focusing on the morphology of the resulting submonolayer Ru modified surfaces. STM results show a pronounced step decoration, indicating that the steps are active sites for the nucleation of Ru monolayer islands, while a random distribution of Ru nuclei is observed on terraces. During deposition, the open circuit potential rapidly increases from 0.38 to above 0.72 V vs. (Ag/AgCl). Experiments with different deposition times show that deposition from sulfuric acid solution saturates after 3 min deposition, the island size reaches its saturation value of 2.8 nm after 1 min. Significantly higher deposition activities and saturation coverages are found for deposition from perchlorate solution and for deposition on highly stepped surfaces/surface areas, indicative of a pronounced anion effect and reflecting the higher activity of steps for Ru deposition, respectively. In both cases, in particular for deposition in perchlorate solution, islands grow to multilayer heights and assume hexagonal shapes. Finally it is shown that multiple deposition can be utilized to reach higher coverages, attaining step saturation also in sulfuric acid solution. The Ru modified Au(1 1 1) electrode was found to be inert for hydrogen adsorption, and the electrochemical results indicate that the ruthenium islands inhibit long-range ordering of the sulfate adlayer on the substrate.",
publisher = "Elsevier",
journal = "Surface Science",
title = "In situ STM imaging of spontaneously deposited ruthenium on Au(111)",
volume = "517",
number = "1-3",
pages = "207-218",
doi = "10.1016/S0039-6028(02)02062-9"
}

Štrbac, S., Behm, R. J., Crown, A.,& Wiȩckowski, A.. (2002). In situ STM imaging of spontaneously deposited ruthenium on Au(111). in Surface Science
Elsevier., 517(1-3), 207-218.
https://doi.org/10.1016/S0039-6028(02)02062-9

Štrbac S, Behm RJ, Crown A, Wiȩckowski A. In situ STM imaging of spontaneously deposited ruthenium on Au(111). in Surface Science. 2002;517(1-3):207-218.
doi:10.1016/S0039-6028(02)02062-9 .

Štrbac, Svetlana, Behm, Rolf Jürgen, Crown, Alechia, Wiȩckowski, Andrzej, "In situ STM imaging of spontaneously deposited ruthenium on Au(111)" in Surface Science, 517, no. 1-3 (2002):207-218,
https://doi.org/10.1016/S0039-6028(02)02062-9 . .