Bonding of H to Ni, Pd, and Pt Surfaces

Eberhardt, W.; Greuter, F.; Plummer, E. W.

doi:10.1103/physrevlett.46.1085

Cited by 299 publications

(72 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In earlier photoemission experiments on hydrogenated bulk Pd no such strong changes of the photoemission spectra after hydrogen exposure were reported. 12 Indeed, the 10 nm spectrum in Fig. 3 does not show strong deviations after hydrogenation, evidencing that a 10 nm thick Pd layer behaves bulk-like.…”

Section: B Photoemission Experimentsmentioning

confidence: 91%

“…A strong change is observed in the spectra for small Pd thicknesses after hydrogen exposure, which is in contrast with existing photoemission data on hydrogenated bulk Pd. 12 The new states are explained in terms of a thin oxide layer, that encapsulates Pd clusters after hydrogenation, the characteristics of the SMSI state. As photoemission has no lateral resolution and depth profiling is difficult due to the cluster geometry, scanning tunneling microscopy (STM) and spectroscopy (STS) are used to confirm the SMSI state of Pd clusters.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Self-Organized Layered Hydrogenation in BlackMg2NiHxSwitchable Mirrors

et al. 2004

View full text Add to dashboard Cite

The morphology and electronic structure of Pd clusters grown on oxidized yttrium surfaces are investigated by scanning tunneling microscopy and ultraviolet photoelectron spectroscopy. The hydrogen sorption mediated by the Pd clusters is determined from the optically monitored switching kinetics of the underlying yttrium film. A strong thickness dependence of the hydrogen uptake is found. The electronic structure of the as-grown Pd clusters depends only weakly on their size. Strong changes of the photoemission spectra are found after hydrogenation, in particular the oxide peak shifts and the Pd peaks vanish. Both phenomena are due to a strong metal-support interaction (SMSI) state, characterized by a complete encapsulation of the clusters by a reduced yttrium oxide layer. Scanning tunneling spectroscopy confirms the SMSI state of small Pd clusters after hydrogen exposure. The SMSI effect is less important with increasing Pd thickness. This explains the critical thickness for the catalyzed hydrogen uptake by the Pd/ YO x / Y system. The results shed light on the mechanism of hydrogen absorption at the triple point gas-catalyst-oxide, which also plays an important role in today's fuel cell technology.

show abstract

Section: B Photoemission Experimentsmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Self-Organized Layered Hydrogenation in BlackMg2NiHxSwitchable Mirrors

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Temperature programmed desorption, photoelectron spectroscopy, and neutron and He atom scattering data have provided indirect evidence for hydrogen occupying stable subsurface sites (6,(11)(12)(13)(14)19). These studies have indicated that the subsurface site is thermodynamically more stable than the bulk site and is of comparable stability to surface-bound hydrogen.…”

mentioning

confidence: 94%

“…For this reason, the adsorption and absorption of hydrogen by Pd has been the subject of much experimental and theoretical work (6,(8)(9)(10)(11)(12)(13)(14). It is known that hydrogen can occupy subsurface sites that are stable absorption sites below the topmost surface layer of Pd atoms.…”

mentioning

confidence: 99%

“…It is known that hydrogen can occupy subsurface sites that are stable absorption sites below the topmost surface layer of Pd atoms. These sites are hypothesized to be important intermediates between hydrogen atoms on the surface and in the bulk (6,(11)(12)(13)(14). Several important chemical reactions are thought to involve subsurface hydrogen in Pd, such as hydrogenation of furan (15), hydrodesulfurization of thiophene (16), and alkene hydrogenation by Pd nanoparticles (17,18).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Observation and manipulation of subsurface hydride in Pd{111} and its effect on surface chemical, physical, and electronic properties

Sykes

Fernandez-Torres

Nanayakkara

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

We report the observation and manipulation of hydrogen atoms beneath the surface of a Pd{111} crystal by using low-temperature scanning tunneling microscopy. These subsurface hydride sites have been postulated to have critical roles in hydrogen storage, metal embrittlement, fuel cells, and catalytic reactions, but they have been neither observed directly nor selectively populated previously. We demonstrate that the subsurface region of Pd can be populated with hydrogen atoms from the bulk by applying voltage pulses from a scanning tunneling microscope tip. This phenomenon is explained with an inelastic excitation mechanism, whereby hydrogen atoms in the bulk are excited by tunneling electrons and are promoted to more stable sites in the subsurface region. We show that this selectively placed subsurface hydride affects the electronic, geometric, and chemical properties of the surface. Specifically, we observed the effects of hydride formation on surface deformation and charge and on adsorbed hydrogen on the surface. Hydrogen segregation and overlayer vacancy ordering on the Pd{111} have been characterized and explained in terms of the surface changes attributable to selective hydrogen occupation of subsurface hydride sites in Pd{111}.atomic manipulation ͉ catalysis ͉ palladium ͉ hydrogen ͉ scanning tunneling microscopy

show abstract