Structures of Na and Cs layers adsorbed on Pt(111)

Cousty, J.; Riwan, R.

doi:10.1016/0039-6028(88)90267-1

Cited by 42 publications

(19 citation statements)

References 28 publications

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“…Atomic Hw as adsorbed on aP t(111)s ubstrate surface at temperatures of 80-90 Kb yd osing H 2 gas through at ube doser. [27] Thes urface coverage of Na was estimated from TPDe xperiments. [25] After hydrogen adsorption on Pt(111), water was adsorbed at the same temperature by backfilling the chamber with H 2 Ov apor at ap artial pressureo f 1 10 À8 torr.T he coverage of H 2 Ow as estimated from TPD measurements [26] and reported in units of water monolayers on Pt(111)( 1ML= 1.2 10 15 molecules cm À2 ).…”

Section: Methodsmentioning

confidence: 99%

The Nature of Hydrated Protons on Platinum Surfaces

Youngsoon

Noh

Jung

et al. 2017

Chemistry A European J

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The nature of hydrated protons formed at water/metal interfaces is one of the most intriguing research questions in the field of interfacial chemistry. We prepared coadsorption layers of hydrogen and water on a Pt(111) surface in ultrahigh vacuum and studied the ionization of adsorbed hydrogen atoms to H ions by employing a combined experimental and theoretical approach. Spectroscopic evidence obtained by mass spectrometry and reflection absorption infrared spectroscopy as well as corresponding density functional theory calculations consistently show that adsorbed hydrogen atoms ionize into multiply hydrated proton species (H O , H O , and H O ) on the surface, rather than H O . Then, upon addition of a water overlayer, the metal-bound hydrated protons spontaneously evolve into three-dimensional fully hydrated proton structures through proton transfer along the water overlayer. The stability of hydrated protons on the Pt surface and their bulk dissolution behavior suggest the possibility that surface hydrated protons are a key intermediate in electrochemical interconversion between adsorbed H atoms and H (aq) in water electrolysis and hydrogen evolution reactions.

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Section: Methodsmentioning

confidence: 99%

The Nature of Hydrated Protons on Platinum Surfaces

Youngsoon

Noh

Jung

et al. 2017

Chemistry A European J

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“…Previous studies [24,25] indicated that full coverage of the Pt film needs 10 15 Na atoms per cm 2 . The % coverage was then calculated by the amount of sodium added during each deposition step.…”

Section: Catalyst System Preparationmentioning

confidence: 99%

Electrochemical Promotion of CO Oxidation on Na-Promoted Pt/YSZ: Interaction Between Multiple Promoting Species

Stavrakakis

Poulidi

2018

Top Catal

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The combined promotional effect of electrochemically-supplied O 2− and chemically-supplied Na + promoters, was studied for the case of CO oxidation on Pt/YSZ. Four different sodium coverages (0.16, 1.6, 8 and 40%) were loaded onto the catalyst surface and the catalytic behaviour was compared with a nominally 'clean' catalyst under a wide range of reactants' ratios under open-circuit and polarised conditions. Sodium generally increased oxygen adsorption by lowering the work function of the catalyst. However, sodium promoted the catalytic rate only at coverages up to 1.6% and worked synergistically with O 2− promoting species to an increased overall promotion of the catalytic rate. At higher sodium coverages, i.e. θ Na ≥ 8%, the catalytic behaviour was strongly affected by the interactions between the sodium species, the catalyst, the reactants and oxygen ions promoting species. The postulated formation of stable sodium oxide species on the catalyst pores reduced the active catalytic area which resulted in poisoning the catalytic rate and suppressing EPOC effect, respectively. It is suggested that these stable sodium oxide species which also induced a permanent EPOC effect by oxygen storage, were formed by the migrated oxygen ions.

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“…superstructure at ¼ 0:33 ML, 77 as in the case of K/Pt(111) described in Section 4.2. As shown in Fig.…”

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confidence: 99%

Photochemistry and Photo-Induced Ultrafast Dynamics at Metal Surfaces

Matsumoto¹

2007

Bulletin of the Chemical Society of Japan

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This account describes excitation mechanisms and ultrafast nuclear dynamics at metal surfaces induced upon photon irradiation. After reviewing possible excitation mechanisms for photochemistry of adsorbates on metal surfaces, we discuss the ultra-violet photochemistry of saturated hydrocarbons, i.e., methane and cyclohexane, on metal surfaces. Although these alkanes in the gas phase do not absorb photons at %6 eV, CH bond dissociation takes place upon 6.4-eV photon irradiation on metal surfaces. Hybridization between CH antibonding orbitals of the alkanes and metal bands, forming a new band across the Fermi level, is proposed to be responsible for both the photochemistry and CH vibrational mode softening. Since electronic relaxation at metal surfaces takes place very rapidly, most of excited adsorbates do not proceed to dissociation and/or desorption, but rather they are vibrationally excited. To probe photo-induced nuclear motions in real time, we developed femtosecond (fs) time-resolved second harmonic generation spectroscopy on metal surfaces. This method was used to explore the dynamics of photo-excited coherent vibration at Pt(111) surfaces covered with alkali-metal atoms. Irradiation of fs pump-laser pulses induced coherent vibrational motions of the stretching vibration of alkali atoms with respect to the metal surface and the Rayleigh modes of the Pt surface, which manifest themselves in modulations of second harmonic intensity of probe pulses. We also demonstrated that selective excitation of a phonon mode can be achieved by using tailored light pulse trains.

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Structures of Na and Cs layers adsorbed on Pt(111)

Cited by 42 publications

References 28 publications

The Nature of Hydrated Protons on Platinum Surfaces

The Nature of Hydrated Protons on Platinum Surfaces

Electrochemical Promotion of CO Oxidation on Na-Promoted Pt/YSZ: Interaction Between Multiple Promoting Species

Photochemistry and Photo-Induced Ultrafast Dynamics at Metal Surfaces

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