Adsorption of small molecules on gold single crystal surfaces

Carabineiro, Sónia A. C.; Nieuwenhuys, B.E.

doi:10.1007/bf03214951

Cited by 70 publications

(59 citation statements)

References 58 publications

(89 reference statements)

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“…1b, 2d), in agreement with previous work. [30] This structure is consistent with the length of (2+n)a of features along the [1][2][3][4][5][6][7][8][9][10] direction, as determined by STM. Within this structure model, features with n>2 darker gold atoms contain (n-2) atoms that are perturbed by two oxygen atoms.…”

Section: Stm Contrast On Oxygen On Au(110) and Its Origin Oxygen Atosupporting

confidence: 85%

“…Atomic O was created by exposing the surface to ozone since O 2 does not measurably dissociate on crystalline gold. [10,12] Directed ozone dosing was performed using a continuous flow from an ozone generator (Ozone Engineering, model LG-7) to the 1 cm-diameter doser, located ~2 mm from the sample surface. Prior to experiments, several cycles of ozone dosing/annealing were performed to ensure a clean dosing line and sample surface.…”

Section: Methodsmentioning

confidence: 99%

“…[2] Because gold is an efficient and selective catalyst for oxidation processes [3][4][5][6][7][8][9] there is considerable interest in imaging reactant species, including adsorbed oxygen (O ads ), on its surfaces. Model studies on single crystal surfaces [10][11][12][13] provide a mechanistic understanding of how oxidative processes are promoted on Au, [14] with the final goal of predicting new reactions. [15] To date, the majority of mechanistic studies have focused on O-covered Au(111), which roughens upon O atom adsorption [16] even at low coverage (0.1ML) and low temperature (~200 K).…”

Section: Introductionmentioning

confidence: 99%

“…[19] Herein, we investigate the bonding of O on Au(110) in order to better exploit atomic-scale imaging using STM in conjunction with DFT studies. The Au(110) surface reconstructs to the missing-row Au(110)-(1x2) structure, which consists of an ordered array of (111) microfacets [20][21][22] capped by rows of atoms with low coordination number along the [1][2][3][4][5][6][7][8][9][10] direction (Fig. 1a).…”

Section: Introductionmentioning

confidence: 99%

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Direct visualization of quasi-ordered oxygen chain structures on Au(110)-(1 × 2)

et al. 2016

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The Au(110) surface offers unique advantages for atomically-resolved model studies of catalytic oxidation processes on gold. We investigate the adsorption of oxygen on Au(110) using a combination of scanning tunneling microscopy (STM) and density functional theory (DFT) methods. We identify the typical (empty-states) STM contrast resulting from adsorbed oxygen as atomic-sized dark features of electronic origin. DFT-based image simulations confirm that chemisorbed oxygen is generally detected indirectly, from the binding-induced electronic structure modification of gold. STM images show that adsorption occurs without affecting the general structure of the pristine Au(110) missing-row reconstruction. The tendency to form onedimensional structures is observed already at low coverage (<0.05ML), with oxygen adsorbing on alternate sides of the reconstruction ridges. Consistently, calculations yield preferred adsorption on the (111) facets of the reconstruction, on a 3-fold coordination site, with increased stability when adsorbed in chains. Gold atoms with two oxygen neighbors exhibit enhanced electronic hybridization with the O states. Finally, the species observed are reactive to CO oxidation at 200K and desorption of CO 2 leaves a clean and ordered gold surface.2

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Section: Stm Contrast On Oxygen On Au(110) and Its Origin Oxygen Atosupporting

confidence: 85%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Direct visualization of quasi-ordered oxygen chain structures on Au(110)-(1 × 2)

et al. 2016

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“…Carbonaceous surfaces will typically adsorb hydrogen at around 4-5 kJ/mol 55 whereas metallated surfaces will form a stronger attraction to hydrogen, often between 5 to 50 kJ/mol depending on the metal alloy, 10 surface roughness and crystallite morphology being tested [56][57][58] . Although the adsorption of extended gold surfaces has been demonstrated to be lower than that of other metals such as palladium of platinum 59 , recent work also demonstrated that small gold clusters lead to enhanced adsorption of hydrogen 60,61 . This is demonstrated in Figure 2 and Figure 15 4, where the average NP size was found to be around 52 and 300 nm (Table 1) …”

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confidence: 99%

Activation of gold decorated carbon nanotube hybrids for targeted gas adsorption and enhanced catalytic oxidation

et al. 2012

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10Free standing assemblies of carbon nanotubes (CNTs), known as bucky-paper, (BP) have been functionalised through the in-situ plating of gold nanoparticles within the interstitial spaces in the BP. The nanoparticles are extremely small and well distributed at short plating times, so much so that the specific surface area of the BP is actually 15 increased by the gold incorporation. These well distributed nanoparticles exhibit high enthalpy hydrogen storage and selective carbon dioxide adsorption over other gases, in particular methane. In concert with the conductive BP substrate, it has been demonstrated that these materials can also act as high turnover heterogeneous catalysts. (Graphical abstract)Keywords 25 gold decorated carbon nanotube; composite bucky-paper; specific gas storage; catalytic activity Self-supporting BPs were processed from chemical vapour deposition grown multi walled CNTs as described in a previous study 51 . Research highlightsIn short, the functionalized CNTs were then suspended in propan-2-ol by 5 repeated cycles of freezing at -17 ºC followed by bath sonication as per the method developed in 50 . The CNT suspension was then filtered on top 10 of a porous poly(ether sulphone) membrane to form a self-supporting BP.BPs were exposed for 10 min to a flow of UV induced ozone in order to form hydroxyl groups at the surface of outer CNT walls 52, 53 . These groups are needed to both facilitate wetting of the CNTs by the plating solutions and as anchors for the initial plating reactions. 15The procedure of electroless gold deposition within porous materials has been described by Martin et al. 54 and was previously used to fabricate pure gold nanotubes 48 in a three step protocol. During the first step, BP properties analysisThe gold content in the structure was determined by Thermo Scanning Electron Micrographs (SEM) at 5 keV, 52 º of tilt and 5 cm working distance. The Gallium (Ga) milling was performed with an initial beam current of 7 nA followed by cleaning steps at 0.1 nA. Eventually, pore size distribution was determined by perm-porometry on a capillary flow porometer from Porous Materials Inc. in wet-up/dry-up mode. 50Galwick and N2 were respectively used as the wetting liquid and to pressurize the BP pores up to 500 psi. Gas adsorptionThe adsorption of N2, CH4 and CO2 was performed at room Catalytic activity determinationBPs were exposed to pure analytical grade pentanal at 70 ºC in oxygenated CDCl3 for times of either 2 or 24 h. The composition of the solution before and after being exposed to the catalytic influence of the 65 BPs were analysed using Nuclear Magnetic Resonance (NMR) on aBruker 400 MHz spectrometer. TGA performed on the series of samples showed an initial diminished thermal stability which was attributed to the ozone treatment inducing defects on the CNT walls. However, after 10 h of plating the 90 stability, compared to a non treated sample, was recovered and improved. C. Results and DiscussionThe samples were all stable up to 400 ºC. The gold content c...

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Catalytic Activities of Au₆, , and Clusters for CO oxidation: A density functional study

Baishya

Deka

2014

Int J of Quantum Chemistry

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We have studied the CO oxidation over neutral, anionic, and cationic gold hexamer clusters using density functional theory which elucidates the effect of cluster charge state on the catalytic activity. Herein, we have considered the conventional bimolecular Langmuir–Hinshelwood mechanism with coadsorbed CO and O2 at the neighboring sites in all the clusters. Among the three clusters, Au 6− entails lower barriers during the various steps of the oxidation mechanism. The stability of all the species including the transition states with respect to the interacting species in Au 6− indicates no thermal activation. Our study suggests better catalytic activity of Au 6− as compared to the neutral and cationic counterparts. © 2014 Wiley Periodicals, Inc.

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Adsorption of small molecules on gold single crystal surfaces

Cited by 70 publications

References 58 publications

Direct visualization of quasi-ordered oxygen chain structures on Au(110)-(1 × 2)

Direct visualization of quasi-ordered oxygen chain structures on Au(110)-(1 × 2)

Activation of gold decorated carbon nanotube hybrids for targeted gas adsorption and enhanced catalytic oxidation

Catalytic Activities of Au₆, , and Clusters for CO oxidation: A density functional study

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Adsorption of small molecules on gold single crystal surfaces

Cited by 70 publications

References 58 publications

Direct visualization of quasi-ordered oxygen chain structures on Au(110)-(1 × 2)

Direct visualization of quasi-ordered oxygen chain structures on Au(110)-(1 × 2)

Activation of gold decorated carbon nanotube hybrids for targeted gas adsorption and enhanced catalytic oxidation

Catalytic Activities of Au6, , and Clusters for CO oxidation: A density functional study

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Catalytic Activities of Au₆, , and Clusters for CO oxidation: A density functional study