Oxygen adsorption on a Pd(111) surface

Surnev, L.; Bliznakov, G.; Кискинова, М.

doi:10.1016/0039-6028(84)90395-9

Cited by 53 publications

(13 citation statements)

References 19 publications

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“…Comparing the experimental WF increase of +0.6 eV (Figure e) with the values obtained from theory (see Table ), we find a good quantitative agreement at 3/12 ML coverage where the theory predicts a WF change of +0.69 eV for Pd(111) and +0.84 eV for Pd 6 C(111). A quantitative agreement is also obtained when considering work done with the macroscopic Kelvin probe technique: a saturation of the WF increase was observed after a few Langmuir ( p O2 = 2.7 × 10 –8 mbar) at RT, with a maximum WF change of +0.8 to +0.9 eV.…”

Section: Discussionsupporting

confidence: 73%

“…A simple experimental method for detecting adsorption and desorption on metal surfaces is to measure related work function (WF) changes of the metal, as exemplified by the macroscopic Kelvin probe technique on single-crystal surfaces. For instance, oxygen and hydrogen dissociatively adsorb on Pd(111) − and increase the WF depending on the coverage: at room temperature, saturation values of +0.8 and +0.3 eV are found for oxygen and hydrogen, respectively. Carbon monoxide increases the WF by up to +1.0 eV, whereas water decreases the WF of metals in general, as in the case of palladium with saturation values of around ∼−0.8 eV .…”

Section: Introductionmentioning

confidence: 99%

“…A strong WF reduction is also observed when carbon is dissolved in a subsurface region (∼−1 eV), which we exemplified at PdNPs . One possibility would therefore be to monitor changes of the NP’s WF when G@NPs are exposed to a gaseous environment: if adsorption or desorption of atomic or molecular species takes place on the NP’s facets, the WF of the G@NP should change proportional to the adsorbate concentration. , The WF of a single NP can be measured by Kelvin probe force microscopy (KPFM), which is an implementation of Kelvin probe into noncontact atomic force microscopy (nc-AFM) . Due to the spacial resolution at the nanometer scale and the mV resolution in WF, KPFM yields WF information of nanometer-sized islands and NPs. ,− …”

Section: Introductionmentioning

confidence: 99%

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Oxygen Adsorption on Graphene-Encapsulated Palladium Nanoparticles Imaged by Kelvin Probe Force Microscopy

Grönbeck

Barth

2019

J. Phys. Chem. C

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Graphene encapsulated metal nanoparticles (G@NPs) offer a possibility to observe confined reactions in the nanocontainer formed by the NP's facets and graphene. However, direct experimental detection of adsorbed atomic and molecular species under the graphene cover is still challenging and the mechanisms of intercalation and adsorption are not well understood. Here we show that Kelvin probe force microscopy (KPFM) can largely contribute to the understanding of adsorption and desorption at the single NP level, which we exemplify by comparing oxygen adsorption experiments obtained at asprepared PdNPs and G@PdNPs, both supported on highly oriented pyrolytic graphite (HOPG) and studied under ultra-high vacuum (UHV) conditions. We show that oxygen adsorption at room temperature occurs at a much higher partial oxygen pressure on G@PdNPs compared to as-prepared PdNPs. Similarly, the removal of oxygen via a reaction with the residual gas of the UHV is slower on the G@PdNPs compared to as-prepared PdNPs. The differences can be explained by a limited facility for reactant and product molecules to enter and desorb from the nanocontainer via the defects of the graphene. Observed WF changes are supported by assisting density functional theory (DFT) calculations. ACKNOWLEDGMENTS Support from the Agence Nationale de la Recherche and the Deutsche Forschungsgemeinschaft (ANR, DFG) through project REACTIVITY (grant ANR-17-CE09-0045) is gratefully acknowledged. H.G. acknowledges support from the Swedish Reserach Council (2016-05234). The calculations were performed at C3SE (Göteborg) via an SNIC grant. C.B. acknowledges J. Murgia and P. Bindzi for maintainance work at the UHV chamber. ASSOCIATED CONTENT Supporting Information. Details about the sample preparation, UHV techniques (STM, nc-AFM and KPFM), image analysis, density functional theory (DFT) calculations, choice of WF values from literature, and supporting experiments and calculations (PDF)

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Section: Discussionsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Oxygen Adsorption on Graphene-Encapsulated Palladium Nanoparticles Imaged by Kelvin Probe Force Microscopy

Grönbeck

Barth

2019

J. Phys. Chem. C

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“…The samples were heated resistively and a chromel-alumel thermocouple (k type) was pressed against the back of the surface to measure the sample temperature. The surfaces were cleaned by exposing them to many cycles of the following: 2 min of oxygen exposure at an equivalent pressure of 10 -2 Torr and 1000 K; 5 min ofAr + sputtering (600eV, 2JlA) at 1000 K; followed by 30 s of annealing in V3.cuum at 1200 K. [24][25][26] After this procedure, no impurities were detected on the surfaces in abundance greater than the detection limit of our Auger spectrometer which was approximately 1 % of a monolayer. Finally, to keep the surfaces free from impurities during reaction, it was necessary to pass the CO through a bed of alumina beads which was heated to approximately 600 K. This trap, which was placed in line between the mass flow controller and the nozzle, served to decompose the nickel tetracarbonyl and iron pentacarbonyl which was present in the CO gas (Matheson CP grade).…”

Section: Methodsmentioning

confidence: 99%

The dynamics of CO oxidation on Pd, Rh, and Pt studied by high-resolution infrared chemiluminescence spectroscopy

Coulston

Haller

1991

The Journal of Chemical Physics

101

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Hydrogen and CO spillover at Cu/Rh(100) bimetallic surfaces studied by highresolution electron energyloss spectroscopy J.Summary Abstract: Coadsorption structures of benzene and carbon monoxide on Rh(111) and Pt(111) by highresolution electron energy loss spectroscopy and lowenergy electron diffractionThe dynamics of carbon monoxide oxidation on Pd, Rh, and Pt foils were probed under nearly collision-free conditions using high resolution infrared chemiluminescence. Auger electron spectroscopy was used to verify the absence of impurities on the surfaces. The reactants were supplied to the surface through a free jet nozzle source, while a Fourier transform infrared spectrometer operating at 0.012 cm -I resolution was used to fully resolve the rotational structure of several vibrational transitions in the product CO 2 (22 in the case of Pd). In all cases, the product CO 2 is vibrationally excited and the apparent vibrational temperatures are in the same order as the peak reaction rates, i.e., Pd> Pt > Rh. The surface coverage of oxygen on Pd was varied by changing the CO:0 2 ratio and the surface temperature and, in both cases, increasing oxygen coverage causes an increase in vibrational excitation of product CO 2 , On Pt and Rh, the apparent temperatures of different vibrational modes are similar, while on Pd, those levels involved in Fermi resonances that are traditionally called the symmetric stretch levels are selectively populated. From these results, evidence that the activated complex is bent on Pd relative to Pt and Rh and, in all cases, is aligned more or less along the surface normal is presented.6932

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“…The interaction of oxygen with Pd has been investigated extensively on single crystals, − foils, , and supported catalysts , in the past decades because of their importance in catalysis. On single-crystal surfaces, the interaction of oxygen with the Pd surface involved several stages such as dissociation and formation of surface oxide.…”

Section: Introductionmentioning

confidence: 99%

Coupling between Adjacent Crystal Planes during CO + O_ad Reaction on a Defective Pd(100) Surface

2001

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Spatially resolved photoemission electron microscopy (PEEM) was employed to investigate the adsorption, diffusion, and reactivity of oxygen on a defective Pd(100) surface. The defective region on Pd(100) exposed several different planes with low indexes, for example, (110) and (111) planes. Upon oxygen adsorption, various types of oxygen species formed on each plane, which behaved with different reactivities toward CO. An obvious coupling between the Pd(110) plane and its adjacent planes was monitored by PEEM during CO + Oad reaction and resulted in the appearance of the reaction-diffusion waves on the Pd (110) plane. The occurrence of reaction coupling had a great influence on the catalytic kinetics of the crystal planes involved. However, during isothermal desorption of adsorbed oxygen on the planes, no coupling existed between adjacent planes, which implied that the reaction played a key role in the occurrence of coupling.

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Oxygen adsorption on a Pd(111) surface

Cited by 53 publications

References 19 publications

Oxygen Adsorption on Graphene-Encapsulated Palladium Nanoparticles Imaged by Kelvin Probe Force Microscopy

Oxygen Adsorption on Graphene-Encapsulated Palladium Nanoparticles Imaged by Kelvin Probe Force Microscopy

The dynamics of CO oxidation on Pd, Rh, and Pt studied by high-resolution infrared chemiluminescence spectroscopy

Coupling between Adjacent Crystal Planes during CO + O_ad Reaction on a Defective Pd(100) Surface

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Oxygen adsorption on a Pd(111) surface

Cited by 53 publications

References 19 publications

Oxygen Adsorption on Graphene-Encapsulated Palladium Nanoparticles Imaged by Kelvin Probe Force Microscopy

Oxygen Adsorption on Graphene-Encapsulated Palladium Nanoparticles Imaged by Kelvin Probe Force Microscopy

The dynamics of CO oxidation on Pd, Rh, and Pt studied by high-resolution infrared chemiluminescence spectroscopy

Coupling between Adjacent Crystal Planes during CO + Oad Reaction on a Defective Pd(100) Surface

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Coupling between Adjacent Crystal Planes during CO + O_ad Reaction on a Defective Pd(100) Surface