Adsorbate-induced segregation in a PdAg membrane model system: Pd3Ag(111)

Svenum, Ingeborg-Helene; Herron, Jeffrey A.; Mavrikakis, Manos; Venvik, Hilde J.

doi:10.1016/j.cattod.2012.01.007

Cited by 45 publications

(38 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The findings have been linked to segregation phenomena [35,42,43,46] as well as roughening of the surface [19,32,35,47,48] and removal of surface impurities [5,42,43,49], but are not fully understood. However, the heat treatment in air is not expected to affect hydrogen solubility in Pd-Ag membranes [19,20].…”

Section: Introductionmentioning

confidence: 93%

Thickness dependent effects of solubility and surface phenomena on the hydrogen transport properties of sputtered Pd77%Ag23% thin film membranes

Vicinanza

Svenum

Næss

et al. 2015

Journal of Membrane Science

View full text Add to dashboard Cite

The hydrogen solubility and permeation in Pd77%Ag23% membranes have been determined as a function of temperature and membrane thickness. Unexpectedly, the solubility of hydrogen is found to systematically increase as the membrane thickness decreases from 11.2 to 2.2 µm. Topography studies by atomic force microscopy in conjunction with previously reported characterization suggest linkage of the hydrogen solubility to the density of grain boundaries. A higher average grain boundary density for thinner membranes results from the nucleation and growth proceeding during membrane fabrication by sputtering. For the membranes and conditions (no membrane pretreatment; 300-400°C; Δp H2 ≤ 2 bar) applied here, surface phenomena affect the hydrogen transport at thicknesses below ~5 µm.Determination of the solubility constants hence allowed extraction of the bulk diffusivity 2 parameters from the permeability measurements over the thicker membranes (6.7-11.2 µm), in good agreement with reported values obtained using other techniques.

show abstract

Section: Introductionmentioning

confidence: 93%

Thickness dependent effects of solubility and surface phenomena on the hydrogen transport properties of sputtered Pd77%Ag23% thin film membranes

Vicinanza

Svenum

Næss

et al. 2015

Journal of Membrane Science

View full text Add to dashboard Cite

show abstract

“…25 In this case, Pd segregates to the surface to form the oxide structure and an enrichment of Ag is observed in the interface layer between the surface oxide and the Pd 75 Ag 25 bulk. Theoretical studies also find adsorbate-induced segregation as a result of oxygen, 14,27 hydrogen, 19,[27][28][29] and CO 27 adsorption.…”

mentioning

confidence: 92%

Reversed Hysteresis during CO Oxidation over Pd₇₅Ag₂₅(100)

et al. 2016

View full text Add to dashboard Cite

CO oxidation over Pd(100) and Pd 75 Ag 25 (100) has been investigated by a combination of near-ambient pressure X-ray photoelectron spectroscopy, quadrupole mass spectrometry, density functional theory calculations and micro-kinetic modeling. For both surfaces, hysteresis is observed in the CO 2 formation during heating and cooling cycles. Whereas normal hysteresis with higher light-off temperature than extinction temperature is present for Pd(100), reversed hysteresis is observed for Pd 75 Ag 25 (100).The reversed hysteresis can be explained from dynamic changes in the surface composition. At the beginning of the heating ramp, the surface is rich in palladium which gives a CO coverage that poisons the surface until the desorption rate becomes sufficiently high. The thermodynamic preference for an Ag rich surface in the absence of adsorbates promotes diffusion of Ag from the bulk to the surface as CO desorbs.During the cooling ramp, an appreciable surface coverage is reached at temperatures too low for efficient diffusion of Ag back into the bulk. The high concentration of Ag in the surface leads to a high extinction temperature and, consequently, the reversed hysteresis.

show abstract

“…Due to its high hydrogen permeability, solubility and reasonable thermal stability at high temperature, palladium is an important membrane material and industrial catalyst that is applied in a number of commercial processes [19,20]. Therefore, Pd has been used as the basis of highly selective hydrogen separation membranes and membrane reactors.…”

Section: Introductionmentioning

confidence: 99%

Investigation on adsorption and decomposition of H2S on Pd (1 0 0) surface: A DFT study

2015

View full text Add to dashboard Cite

Adsorbate-induced segregation in a PdAg membrane model system: Pd3Ag(111)

Cited by 45 publications

References 81 publications

Thickness dependent effects of solubility and surface phenomena on the hydrogen transport properties of sputtered Pd77%Ag23% thin film membranes

Thickness dependent effects of solubility and surface phenomena on the hydrogen transport properties of sputtered Pd77%Ag23% thin film membranes

Reversed Hysteresis during CO Oxidation over Pd₇₅Ag₂₅(100)

Investigation on adsorption and decomposition of H2S on Pd (1 0 0) surface: A DFT study

Contact Info

Product

Resources

About

Adsorbate-induced segregation in a PdAg membrane model system: Pd3Ag(111)

Cited by 45 publications

References 81 publications

Thickness dependent effects of solubility and surface phenomena on the hydrogen transport properties of sputtered Pd77%Ag23% thin film membranes

Thickness dependent effects of solubility and surface phenomena on the hydrogen transport properties of sputtered Pd77%Ag23% thin film membranes

Reversed Hysteresis during CO Oxidation over Pd75Ag25(100)

Investigation on adsorption and decomposition of H2S on Pd (1 0 0) surface: A DFT study

Contact Info

Product

Resources

About

Reversed Hysteresis during CO Oxidation over Pd₇₅Ag₂₅(100)