X-ray photoelectron spectroscopic studies of cadmium- and silver-oxygen surfaces

Hammond, John S.; Gaarenstroom, Stephen W.; Winograd, Nicholas

doi:10.1021/ac60363a019

Cited by 305 publications

(150 citation statements)

References 30 publications

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“…Despite the adoption of special precautions to minimize air exposure, interaction with the outer atmosphere could not be completely avoided, leading to the presence of chemical species different from the sole metallic silver. Such behavior, whose occurrence confirms the well-known complexity of the Ag-O system, 41,42 reflected the silver reactivity towards oxygencontaining species, 43 enhanced in the present case by the FIG. 4.…”

Section: ͑1͒supporting

confidence: 85%

“…42,44 However, other species could also be responsible for the latter band, including hydroxyl groups and adsorbed H 2 O/O 2 . 41,42 As a general rule, both the O1s and the C1s signals showed a higher CO 3 2− /HCO 3 − contribution for samples characterized by a lower silver content. This effect could be explained taking into account that the latter specimens have a lower particle size ͑see above͒, thus being the most reactive to atmosphere due to their nanostructure.…”

Section: Figmentioning

confidence: 76%

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Silica-supported silver nanoparticles: Tailoring of structure-property relationships

Barreca

Gasparotto

Maragno

et al. 2005

Journal of Applied Physics

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Silica-supported silver nanoparticles were obtained by rf sputtering from Ar plasmas under soft synthesis conditions, with particular attention to the combined influence of rf power and total pressure on the system composition, nanostructure, morphology, and optical properties. In order to attain a thorough insight into the nucleation and growth phenomena of Ag nanoparticles on the silica substrate, several in situ and ex situ characterization techniques were used. In particular, a laser reflection interferometry system was employed for a real-time monitoring of the deposition process, providing useful and complementary information with respect to the other ex situ techniques ͑x-ray photoelectron spectroscopy and x-ray excited Auger electron spectroscopy, glancing incidence x-ray diffraction, atomic force microscopy, optical-absorption spectroscopy, and transmission electron microscopy͒. The above investigations evidenced the formation of silver-based nanosystems ͑average crystallite size ഛ10 nm͒, whose features ͑metal content, Ag particle size and shape, structure and optical properties͒ could be carefully tailored by moderate and controlled variations of the synthesis parameters.

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Section: ͑1͒supporting

confidence: 85%

Section: Figmentioning

confidence: 76%

Silica-supported silver nanoparticles: Tailoring of structure-property relationships

Barreca

Gasparotto

Maragno

et al. 2005

Journal of Applied Physics

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“…18,19 The oxide (CdTeO 3 ) was also confirmed by the BE difference parameter, BE(O1s)-BE(Cd3d 5/2 ), i.e., $124.7.0 eV, which matches with the literature. 20,25 In the present study, the Cd 3d 5/2 peak was found at 405.5 eV, although this peak is also asymmetric, as shown in Fig. 5.…”

Section: Oxidessupporting

confidence: 48%

Surface Studies on HgCdTe Using Non-aqueous Iodine-Based Polishing Solution

Nokhwal

Srivastav

Goyal

et al. 2017

Journal of Elec Materi

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Bromine-and iodine-based solutions were compared for surface preparation of HgCdTe epilayers. The iodine (I)-potassium iodide (KI)-based non-aqueous solution for surface preparation of mercury cadmium telluride (HgCdTe) epilayers is less corrosive, less toxic and technologically more suitable compared to the widely used bromine-based etchants. It provides improved surface morphology and a lower amount of oxides. A comparative study of the oxide content and elemental tellurium residue on the polished surface was made by x-ray photoelectron spectrometry measurements. Least elemental Te content was observed on the HgCdTe surface polished with I-KI solution as compared to bromine-based etchants. It may result in reduced trap density at the surface of HgCdTe. The possibility of potassium diffusion due to I-KI polishing at the HgCdTe surface, as well as at the cadmium zinc telluride (CdZnTe)-HgCdTe interface, has been ruled out using secondary ion mass spectrometry. Performance of photodiodes fabricated on the polished epilayers (Hg 0.7 Cd 0.3 Te) was assessed and the zero bias dynamic resistance area product (R 0 A) was measured as >5 9 10 4 X cm 2 under stray illumination.

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“…This suggests that there are two different states of metallic silver on the surface, where the difference in binding energy between the two states can be explained by the difference of the charge effect. As reported by Hammond et al [37] Ag is unusual in that its core-level photoemissions shift to lower binding energy with increasing oxidation state. The binding energy of Ag 3d5/2 in AgAl2O3, is 368.0, which are consistent with the binding energies of Ag 3d5/2 in Ag2O, according to the literature values of 367.9 eV [37].…”

Section: X-ray Photoelectron Spectroscopy (Xps)mentioning

confidence: 65%

“…As reported by Hammond et al [37] Ag is unusual in that its core-level photoemissions shift to lower binding energy with increasing oxidation state. The binding energy of Ag 3d5/2 in AgAl2O3, is 368.0, which are consistent with the binding energies of Ag 3d5/2 in Ag2O, according to the literature values of 367.9 eV [37]. In addition, a shoulder at 368.5 eV for Ag/Al2O3 might be attributed to Ag 0 (Ag 3d5/2 = 368.4 eV) on the surface.…”

Section: X-ray Photoelectron Spectroscopy (Xps)mentioning

confidence: 65%

Studies on H2-Assisted Liquefied Petroleum Gas Reduction of NO over Ag/Al2O3 Catalyst

Yadav

Thakur

et al. 2017

Bull. Chem. React. Eng. Catal.

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Hydrocarbon-Selective catalytic reduction (HC-SCR) is one of the potential methods to remove NOx emissions from diesel engine, lean burn petrol engines and natural gas engines exhaust. Ag/Al2O3 is a good catalyst for HC-SCR of NOx under lean-burn conditions. Further, addition of small amount of H2 is effective for enhancing HC-SCR activity. This effect is unique to silver and to specific Ag/support combinations, namely, Ag/γ-Al2O3. Various HC reductants, such as: octane, decane, dodecane and propane, have been reported in the literatures. Only a single study on LPG as a reductant over Cu-ZSM catalyst was reported. There was no work reported on H2 assisted LPG over Ag/Al2O3 catalyst. Thus, this gap in the literature is filled with the present investigation of NO reduction over 2 wt.% Ag/Al2O3 catalyst using LPG reductant. The fresh and used catalyst was characterized by various techniques like low temperature N2-adsorption, XRD, XPS and SEM. There was practically no change in the characteristics of the fresh and used catalyst. Two different reductants of CO and LPG were compared for SCR of NO over the catalyst without and with H2-assisted. The experiments were performed in a fixed bed tubular flow reactor under the following conditions: 100mg catalyst; 0.13% NO, 2.5% LPG/CO, 1% H2, 10% O2, rest Ar; total flow rate 60 mL/min; temperature ambient 400 o C and pressure 1 atm. Around 100% conversion of NO was achieved using LPG reductant. Light off temperature of NO reduction significantly reduced by H2assisted LPG reductant. The maximum conversion of NO with CO was limited to 35.15% at temperature of 224 o C and above. Whereas, 97.79 % NO conversion was achieved at 365 o C with LPG reductant. While, the maximum conversions with H2-LPG and H2-CO reductants were 100 and 99.46% at 117 and 220 o C, respectively. Therefore, H2-LPG-SCR of NOx over 2 wt.% Ag/Al2O3 catalyst system can be used to get 100% reduction at low temperature.

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X-ray photoelectron spectroscopic studies of cadmium- and silver-oxygen surfaces

Cited by 305 publications

References 30 publications

Silica-supported silver nanoparticles: Tailoring of structure-property relationships

Silica-supported silver nanoparticles: Tailoring of structure-property relationships

Surface Studies on HgCdTe Using Non-aqueous Iodine-Based Polishing Solution

Studies on H2-Assisted Liquefied Petroleum Gas Reduction of NO over Ag/Al2O3 Catalyst

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