Initial Subsurface Incorporation of Oxygen into Ru(0001): A Density Functional Theory Study

Cai, Jianqiu; Luo, Haijun; Tao, Xinyong; Tan, Ming-Qiu

doi:10.1002/cphc.201500681

Cited by 8 publications

(7 citation statements)

References 72 publications

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“…The CE model would be a good description of the dataset in the λ → ∞ limit. The value of ∆E = 165 ± 9 meV obtained is significantly smaller than previous density functional theory (DFT) estimates [32,33]. The discrepancy may result in part from the zero-point-energy of a particle occupying a hcp site relative to the fcc site.…”

contrasting

confidence: 65%

Ultrafast Diffusion at the Onset of Growth: O/Ru(0001)

et al. 2021

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Nanoscopic clustering in a 2D disordered phase is observed for oxygen on Ru(0001) at low coverages and high temperatures. We study the coexistence of quasi-static clusters (with a characteristic length of ∼ 9Å) and highly mobile atomic oxygen which diffuses between the energy-inequivalent, threefold hollow sites of the substrate. We determine a surprisingly low activation energy for diffusion of 385 ± 20 meV. The minimum of the O − O interadsorbate potential appears to be at lower separations than previously reported.

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confidence: 65%

Ultrafast Diffusion at the Onset of Growth: O/Ru(0001)

et al. 2021

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“…Limited literature exists on the oxidation mechanics of Ru nanoparticles or clusters. Most reports are experimental or theoretical studies of surface oxidation of the Ru [0001] surfaces. − Some work has focused on subsurface oxidation produced by the growth of RuO 2 . ,,, DFT studies have shown that the oxidation of subsurface layers requires more than a monolayer of absorbed oxygen, and the process is enhanced by defects. Interestingly, these studies also found that the energy of formation of oxides is lower on fcc-tetra than hcp-tetra sites. , Other work has highlighted that the Ru [101̅0] direction requires less oxygen to produce RuO 2 (100) at atmospheric pressures .…”

Section: Resultsmentioning

confidence: 99%

“…Most reports are experimental or theoretical studies of surface oxidation of the Ru [0001] surfaces. − Some work has focused on subsurface oxidation produced by the growth of RuO 2 . ,,, DFT studies have shown that the oxidation of subsurface layers requires more than a monolayer of absorbed oxygen, and the process is enhanced by defects. Interestingly, these studies also found that the energy of formation of oxides is lower on fcc-tetra than hcp-tetra sites. , Other work has highlighted that the Ru [101̅0] direction requires less oxygen to produce RuO 2 (100) at atmospheric pressures . The work of Herd et al contains the most in-depth explanation of the growth of RuO 2 on Ru [0001] surfaces. ,,, Their main finding was that the foundation of Ru oxidation is the formation and clustering of Ru–O at single-atomic step sites during corrosion.…”

Section: Resultsmentioning

confidence: 99%

“…53−61 Some work has focused on subsurface oxidation produced by the growth of RuO 2 . 55,59,61,62 DFT studies have shown that the oxidation of subsurface layers requires more than a monolayer of absorbed oxygen, and the process is enhanced by defects. Interestingly, these studies also found that the energy of formation of oxides is lower on fcc-tetra than hcp-tetra sites.…”

Section: Rumentioning

confidence: 99%

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In Situ Observation of Metal to Metal Oxide Progression: A Study of Charge Transfer Phenomenon at Ru–CuO Interfaces

et al. 2019

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Surface charge and charge transfer between nanoclusters and oxide supports are of paramount importance to catalysis, surface plasmonics, and optical energy harvesting areas. At present, high-energy X-rays and theoretical investigation are always required to determine the chemical state changes in the nanoclusters and the oxide supports, as well as the underlying transfer charge between them. This work presents the idea of using chrono-conductometric measurements to determine the chemical states of the Ru nanoclusters on CuO supports. Both icosahedral and single-crystal hexagonal close-packed Ru nanoclusters were deposited through gas-phase synthesis. To study the charge transfer phenomenon at the interface, a bias was applied to cupric oxide nanowires with metallic nanocluster decoration. In situ conductometric measurements were performed to observe the evolution of Ru into RuO x under heating conditions. Structural elucidation techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, and Kelvin probe force microscopy were employed to study the corresponding progression of structure, chemical ordering, and surface potential, respectively, as Ru(0) was oxidized to RuO x on the supporting oxide surface. Experimental and theoretical investigation of charge transfer between the nanocluster and oxide support highlighted the importance of metallic character and structure of the nanoclusters on the interfacial charge transfer, thus allowing the investigation of surface charge behavior on oxide-supported catalysts, in situ, during catalytic operation via conductometric measurements.

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“…20,23 Nevertheless, the values we obtain in both cases are rather similar, suggesting that the CO of O in the hcp site than in the fcc site. 8,26,62,63 Interestingly, the oxidation energy is in both cases smaller than the desorption energy. Nonetheless, this result alone is insufficient to determine the likeliness of one process over the other, since it may hide the existence of energy barriers along the reaction paths.…”

Section: Co Desorption and Oxidation On The Honeycomb Structurementioning

confidence: 94%

Insights into the Coadsorption and Reactivity of O and CO on Ru(0001) and Their Coverage Dependence

Tetenoire,

Juaristi,

Alducin

2021

Preprint

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Using density functional theory and an exchange-correlation functional that includes the van der Waals interaction, we study the coadsorption of CO on Ru(0001) saturated with 0.5ML of oxygen. Different coexisting CO coverages are considered that are experimentally motivated, the room temperature coverage consisting in 0.5ML-O+0.25ML-CO (low coverage), the saturation coverage achieved at low temperatures (0.5ML-O+0.375ML-CO, intermediate coverage), and the equally mixed monolayer that is stable according to our calculations but not experimentally observed yet (0.5ML-O+0.5ML-CO, high coverage). For each coverage, we study the competition between the desorption and oxidation of CO on the corresponding optimized structure by analyzing their reaction energies and minimum energy reaction paths. The desorption process is endothermic at all coverages, although the desorption energy decreases as the CO coverage increases. The process itself (and also the reverted adsorption) becomes more involved at the intermediate and high coverages because of the appearance of a physisorption well and concomitant energy barrier separating it from the chemisorbed state. Remarkably, the oxidation of CO, which is endothermic at low coverages, turns exothermic at the intermediate and high coverages. In all cases, the minimum reaction path for oxidation, that involves the chemisorbed and physisorbed CO 2 , is ruled by one of the large energy barriers that protect these molecular states. Altogether, the larger activation energies for oxidation as compared to those for desorption and the extreme complexity of the oxidation against the desorption paths explain that CO desorption dominates over the oxidation in experiments.

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Initial Subsurface Incorporation of Oxygen into Ru(0001): A Density Functional Theory Study

Cited by 8 publications

References 72 publications

Ultrafast Diffusion at the Onset of Growth: O/Ru(0001)

Ultrafast Diffusion at the Onset of Growth: O/Ru(0001)

In Situ Observation of Metal to Metal Oxide Progression: A Study of Charge Transfer Phenomenon at Ru–CuO Interfaces

Insights into the Coadsorption and Reactivity of O and CO on Ru(0001) and Their Coverage Dependence

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