An XPS and TPD study of gold oxide films obtained by exposure to RF-activated oxygen

Stadnichenko, A. I.; Кощеев, С. В.; Boronin, A. I.

doi:10.1134/s0022476615030245

Cited by 17 publications

(9 citation statements)

References 55 publications

(70 reference statements)

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“…None of the Au 4f 7/2 spectra showed any sign of Au oxides. These oxides would be expected around 85.2–86.0 eV − (indicated by the yellow region in Figure ). The largest difference can be observed between the spectrum of the clean Au(310) surface and that obtained with 0.5 ML D 2 O(ads).…”

Section: Resultsmentioning

confidence: 94%

A Comparison of CO Oxidation by Hydroxyl and Atomic Oxygen from Water on Low-Coordinated Au Atoms

2016

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The catalytic oxidation of CO is studied at low-coordinated Au atoms using a single-crystal approach. Electron irradiation activates an otherwise unreactive overlayer of undissociated D2O on Au(310). A low-coverage D2O/O mixture is subsequently allowed to react at surface temperatures from 105 K upward, with CO supplied from the gas phase. X-ray photoelectron spectroscopy shows the absence of Au oxides and quantifies various O-containing species during the reaction. The dependency of the reaction rate on the surface temperature yields an activation energy for the Langmuir–Hinshelwood reaction of O(ads) and CO(ads) between 26 ± 4 and 42 ± 5 kJ/mol. The presented results provide evidence that O(ads) and not OH(ads) is the active reactant on small Au nanoparticles. In addition, the observations suggest that water has a negative effect on the reactivity of O(ads).

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Section: Resultsmentioning

confidence: 94%

A Comparison of CO Oxidation by Hydroxyl and Atomic Oxygen from Water on Low-Coordinated Au Atoms

2016

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“…In addition, two peaks appeared at 85.00 and 89.19 eV in Figure 3a(iii), which was assigned to ionic Au species (Au δ+ ). [ 41,42 ] These two peaks may be attributed to the bonding between Au and glass. [ 43–45 ] This implies that Au bonded with glass and provided good stability, which agrees with the SEM results.…”

Section: Resultsmentioning

confidence: 99%

Self‐Assembly Silver Nanoparticles Decorated on Gold Nanoislands for Label‐Free Localized Surface Plasmon Resonance Biosensing

Liu

Qiu

Chan

et al. 2022

Adv Materials Inter

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scattering and unique surface plasmon absorption spectrum induced by the coherent oscillation form the basis of utilization of LSPR effect in surface-enhanced Raman spectroscopy, [1,3] photoelectronic devices, [4] biosensing, [5] thermoplasmonics, [6] plasmonic filter, [7,8] and photocatalysis. [9] Among the applications, LSPR biosensors as an efficient and reliable platform in clinical biomolecule detection have gained extensive interest due to their ability to conduct measurements in a labelfree and real-time manner. [10] In affinitybased target-specific LSPR biosensing, the local refractive index (RI) changes when diverse biological receptors immobilized on the surface of the nanostructure, e.g., aptamer, antibody, and enzyme react with the targets of interest, which leads to the variation of surface plasmon wave. In this way, LSPR biosensors are capable to detect specific analytes.It is reported that electromagnetic (EM) near-field enhancement due to coupling of EM wave can be induced by metal nanostructures with the configurations of narrow gaps [11][12][13][14] and structures with small radius of curvature, [15][16][17] such as nanoparticles, nanobranches, and nanodendrites. The intensified EM near-field enhanced by the coupling effect, also known as hot spots, has been intensively investigated in both experiments and computer simulations. [18] The hot spots are confined within only a tiny region of nanometer length scale near the surface of the nanostructure and decays exponentially thereafter. [19] It is reported that the hot spots possess higher sensitivity to local changes of RI and the presence of local binding events over other locations due to the coupled resonance effect. [11,18,20] In order to improve the sensitivity of the LSPR biosensor, one of the strategies is to make use of the hot spots and generate efficient overlap between localized nearfields and target. Kim and co-workers [21] have proved that the SPR detection limit (LOD) of sensing biotin-streptavidin can be improved by more than two orders of magnitude through selective functionalization at the hot spots. In our previous studies, the gold nanoislands (AuNIs) were developed as a promising LSPR nanostructure. [22][23][24] They provided better biosensing sensitivity, and with dielectric functionalization also possible at the gaps. It was also shown, through finite difference time domain A nanostructure of self-assembly silver nanoparticles decorated on gold nanoislands (SAM Ag@AuNIs) is proposed in this article as a sensitive sensing medium for localized surface plasmon resonance (LSPR) biosensing applications. A wide tunable plasmonic sensing range from 472 to 552 nm is found by adjusting the Au-Ag atomic ratio. Biotin is employed as an indicator to investigate the potential biosensing applicability and site-specific bioactivity of the SAM Ag@AuNIs. In virtue of a white light common-path sensing system, direct adsorption of biotin on the SAM Ag@AuNIs is measured in label-free manner with detection limit (LOD) of 2.9 pg mL −1 (11.87 × 10 ...

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“…1 Gold oxides have previously been prepared by oxidation of gold in highly reactive chemical environments, such as reactive sputtering in an oxygen atmosphere, 2,3 ozone, [4][5][6][7] and oxygen plasma. [8][9][10][11][12][13] These oxides have also been prepared using an air corona discharge 14 and via laser deposition in oxygen. 15 The gold oxides that occurred on the gold electrodes of microelectromechanical system (MEMS) devices after the release of organic sacrificial layers caused by exposure to oxygen plasma were also characterized.…”

Section: Introductionmentioning

confidence: 99%

“…X-ray photoelectron spectroscopy (XPS) 27,28 is a useful method for characterization of thin gold oxide layers on gold films. The gold oxides, which were prepared via various methods, all decomposed immediately at higher temperatures, 2,5,[7][8][9]11,13,18,19,21 while they decomposed relatively slowly at room temperature. 9,12 The gold oxides were also found to contain oxygen species other than the gold oxides and these species remained stable at higher temperatures.…”

Section: Introductionmentioning

confidence: 99%

Reaction Monitoring of Gold Oxides Prepared by an Oxygen-dc Glow Discharge from Gold Films in Various Aqueous Solutions by a Surface Plasmon Resonance-based Optical Waveguide Sensing System and X-ray Photoelectron Spectroscopy

et al. 2020

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The chemical properties of thin (~0.6 nm) gold oxide layers prepared by an oxygen-dc glow discharge from gold films at room temperature in various solvents and solutions were studied using a surface plasmon resonance (SPR)-based optical waveguide sensing system and X-ray photoelectron spectroscopy (XPS). New insights into the stability and reactivity of gold oxides under these conditions were obtained. The O 1s XPS spectra show three oxygen species, comprising components I, II, and III, in the gold oxides and components I and II are present in this order from the top surface of the oxide (component III). The gold oxide is stable in various solvents (water, methanol, ethanol, acetone, acetonitrile, diethyl ether, chloroform, hydrocarbons) for 10-30 min at room temperature. The gold oxide decomposes in aqueous 10 −2 M solutions of acetaldehyde, hydrochloric acid, and sodium hydroxide during these periods. Gold oxide decomposition in these solutions was monitored by SPR and the decomposition rates were obtained. Decomposition of the gold oxides was confirmed and their surfaces were characterized after decomposition by XPS.

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An XPS and TPD study of gold oxide films obtained by exposure to RF-activated oxygen

Cited by 17 publications

References 55 publications

A Comparison of CO Oxidation by Hydroxyl and Atomic Oxygen from Water on Low-Coordinated Au Atoms

A Comparison of CO Oxidation by Hydroxyl and Atomic Oxygen from Water on Low-Coordinated Au Atoms

Self‐Assembly Silver Nanoparticles Decorated on Gold Nanoislands for Label‐Free Localized Surface Plasmon Resonance Biosensing

Reaction Monitoring of Gold Oxides Prepared by an Oxygen-dc Glow Discharge from Gold Films in Various Aqueous Solutions by a Surface Plasmon Resonance-based Optical Waveguide Sensing System and X-ray Photoelectron Spectroscopy

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