PEEM study of work function changes in Cu, Au and Pd metal surfaces with surface acoustic wave propagation

Nishiyama, Hiroshi; Inoue, Y.

doi:10.1016/j.susc.2006.03.047

Cited by 15 publications

(16 citation statements)

References 28 publications

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“…Introducing propagating deformation waves into materials for adsorption has been extensively evaluated by the methods of both 'surface acoustic waves' (SAW) and resonance oscillation (RO) of bulk acoustic waves (158) . Dynamic lattice distortion induced either through the surface or the bulk material supporting a catalytic surface changes local interatomic distances introducing electronic variation of the local band structure and work function (159) . As described in detail by Yasunobu Inoue, these controlled variations have been implemented in a variety of materials with extensive capability for manipulating adsorption and enhancing catalysis (160) .…”

Section: Page 12mentioning

confidence: 99%

The Catalytic Mechanics of Dynamic Surfaces: Stimulating Methods for Promoting Catalytic Resonance

et al. 2020

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Transformational catalytic performance in rate and selectivity is obtainable through catalysts that change on the time scale of catalytic turnover frequency. In this work, dynamic catalysts are defined in the context and history of forced and passive dynamic chemical systems, with classification of unique catalyst behaviors based on temporally-relevant linear scaling parameters. The conditions leading to catalytic rate and selectivity enhancement are described as modifying the local electronic or steric environment of the active site to independently accelerate sequential elementary steps of an overall catalytic cycle. These concepts are related to physical systems and devices that stimulate a catalyst using light, vibrations, strain, and electronic manipulations including electrocatalysis, back-gating of catalyst surfaces, and introduction of surface electric fields via solid electrolytes and ferroelectrics. These catalytic stimuli are then compared for capability to improve catalysis across some of the most important chemical challenges for energy, materials, and sustainability. File list (2) download file view on ChemRxiv Perspective_Manuscript_ChemRxiv.pdf (3.88 MiB) download file view on ChemRxiv Perspective_Supporting_Information_ChemRxiv.pdf (149.75 KiB)

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Section: Page 12mentioning

confidence: 99%

The Catalytic Mechanics of Dynamic Surfaces: Stimulating Methods for Promoting Catalytic Resonance

et al. 2020

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“…[9] On/off experiments with photoelectron emission microscopy (PEEM) demonstrated that SAWs cause reversible changes of the work function (WF) on the metal surfaces of copper, palladium and gold. [10] Based on these results,itwas concluded, that the catalytic promotion effect is due to electronic effects induced by SAWs. [3] Strain is known to affect the reactivity of solid surfaces,but in order to cause significant changes in the activation barriers of surface processes,t he lattice constant should change by at least 10 À3 .…”

Section: Introductionmentioning

confidence: 93%

On the Promotion of Catalytic Reactions by Surface Acoustic Waves

et al. 2020

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Surface acoustic waves (SAW) allow to manipulate surfaces with potential applications in catalysis,s ensor and nanotechnology.SAWswere shown to cause astrong increase in catalytic activity and selectivity in many oxidation and decomposition reactions on metallic and oxidic catalysts. However,t he promotion mechanism has not been unambiguously identified. Using stroboscopic X-ray photoelectron spectro-microscopy, we were able to evidence as ub-nanosecond work function change during propagation of 500 MHz SAWs on a9nm thick platinum film. We quantify the work function change to 455 meV.S uch as mall variation rules out that electronic effects due to elastic deformation (strain) play am ajor role in the SAW-induced promotion of catalysis.I n asecond set of experiments,SAW-induced intermixing of afive monolayers thick Rh film on top of polycrystalline platinum was demonstrated to be due to enhanced thermal diffusion caused by an increase of the surface temperature by about 75 K when SAWs were excited. Reversible surface structural changes are suggested to be am ajor cause for catalytic promotion.

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“…In On/Off-Experimenten fanden Inoue et al jedoch grçßere,d urch SAWs induzierte WF-¾nderungen auf Kupfer-, Gold-und Palladiumoberflächen. [10] Diese WF-¾nderungen waren nicht vollständig reversibel -n ur zu etwa 60-70 %-und hatten beim Auftreten und verschwinden eine Zeitkonstante von mehreren zehn Sekunden. Da die PEEM-Intensitätnicht kalibriert wurde,PEEM jedoch in der Lage ist, WF-Veränderungen ab !…”

Section: Angewandte Chemieunclassified

“…Work Function, WF) auf den Metalloberflächen von Kupfer, Palladium und Gold verursachen. [10] Aufd er Grundlage dieser Ergebnisse wurde der Schluss gezogen, dass der katalytische Promotionseffekt auf elektronische Effekte zurückzuführen ist, die durch SAWs hervorgerufen werden. [3] Es ist bekannt, dass Gitterverzerrungen die Reaktivitätv on Festkçrperoberflächen beeinflussen.…”

Section: Introductionunclassified