Terrace width effect on adsorbate vibrations: a comparison of Pt(335) and Pt(112) for chemisorption of CO

Xu, Jian; Yates, John T.

doi:10.1016/0039-6028(94)00849-3

Cited by 130 publications

(140 citation statements)

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“…38,50 In this matter, long-range effect of steps in (111) terraces might be inferred from the examination of stretching frequencies of adsorbed CO on stepped surfaces containing terraces of different widths. 51 In electrochemical environments, this topic has been addressed by Rodes et al 52 for adsorbed CO on a series of Pt …”

Section: Discussionmentioning

confidence: 99%

Understanding the CO Preoxidation and the Intrinsic Catalytic Activity of Step Sites in Stepped Pt Surfaces in Acidic Medium

2015

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In order to deepen the knowledge about the origin of the CO pre-oxidation process and the intrinsic catalytic activity of Pt superficial steps toward CO oxidation were performed a series of CO stripping experiments on stepped Pt electrodes in acidic medium. For the occurrence of CO pre-oxidation, it was found that it arises (reproducibly) whenever four interconnected conditions are simultaneously fulfilled: (1) CO adsorption at potentials lower than about 0.2 V; (2) on surfaces saturated with CO ads ; (3) in presence of traces of CO in solution; (4) in presence of surface steps. If any of these four conditions is not satisfied, the CO pre-oxidation pathway does not appear, even though the steps on the electrode surface are completely covered by CO.By controlling the removal of the CO adlayer (voltammetrically), we show that once the CO adlayer has been partially oxidized, the (111) terrace sites of stepped surfaces are released earlier than the (110) step sites. Moreover, if (110) steps are selectively decorated with CO, its oxidation occurs only at potentials ~150 mV higher than the CO pre-oxidation peak. Our results systematically demonstrate that step sites are less active to oxidize CO than those ones responsible for the CO pre-oxidation process. Once the sites responsible for the CO pre-oxidation are made free, there is no apparent motion of the remaining adsorbed CO layer, suggesting that the activation of the surface controls This is a previous version of the article published by ACS in The Journal of Physical Chemistry C. 2015, 119(35): 20272-20282. doi:10.1021/acs.jpcc.5b05386 2 the whole process, rather than the diffusion of CO ads towards hypothetically "most active sites". Voltammetric and chronoamperometric experiments performed on partially covered CO adlayers suggest that adsorbed CO behave as a motionless species during its oxidation, in which the CO adlayer is removed piece by piece. By means in situ FTIR experiments the stretching frequency of CO selectively adsorbed on (110) step sites was examined. Band frequency results confirm that those molecules adsorbed on steps are fully coupled with the adsorbed CO on (111) terraces when the surface reaches full coverage.

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Section: Discussionmentioning

confidence: 99%

Understanding the CO Preoxidation and the Intrinsic Catalytic Activity of Step Sites in Stepped Pt Surfaces in Acidic Medium

2015

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“…There, on-top at steps is more strongly binding than at (111) terraces. [27][28][29] A strong adsorption at edges is thus also expected. This is in sharp contrast to Pd nanoparticles, where edges are disfavored and three-fold hollow sites at (111) facets are the most favorable adsorption sites.…”

Section: Doi: 101002/adma201004064mentioning

confidence: 99%

Ligand Effects in SCILL Model Systems: Site‐Specific Interactions with Pt and Pd Nanoparticles

et al. 2011

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“…This result implies that adsorbed CO might escape from Pt surface due to increased hydrogen adsorption. Adsorption of CO on Pt single crystal surface has shown that CO molecules preferential adsorb directly onto the atop sites rather than adsorbing on bridge sites [8][9][10][11]. Watson et al used ab initio calculations to simulate the adsorption energy of hydrogen on atop Pt surface sites, bridge sites and hollow sites indicating that atop sites provided a more favorable adsorption energy than other adsorption sites [12,13].…”

Section: Resultsmentioning

confidence: 98%

Infrared Study of Benzene Hydrogenation on Pt/SiO2 Catalyst by Co-adsorption of CO and Benzene

Chen¹,

Lin²,

Chen

et al. 2005

Catal Lett

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FT-IR spectra of the co-adsorption of benzene and CO have been performed to identify the preferred adsorption sites of hydrogen and benzene on a Pt/SiO 2 catalyst for hydrogenation of benzene. Results of CO adsorbed on atop sites on Pt/SiO 2 includes: an a peak at 2091 cm )1 , a b peak at 2080 cm )1 and a c peak at 2067 cm )1 indicating three kinds of adsorption sites for dissociative hydrogen on Pt/SiO 2 . The site of lowest CO stretching frequency offers stronger adsorbates-metal interaction for benzene and hydrogen. Hydrogen binding on the site of lowest CO stretching frequency before benzene adsorption significantly enhances the reaction rate of benzene hydrogenation.

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Terrace width effect on adsorbate vibrations: a comparison of Pt(335) and Pt(112) for chemisorption of CO

Cited by 130 publications

References 32 publications

Understanding the CO Preoxidation and the Intrinsic Catalytic Activity of Step Sites in Stepped Pt Surfaces in Acidic Medium

Understanding the CO Preoxidation and the Intrinsic Catalytic Activity of Step Sites in Stepped Pt Surfaces in Acidic Medium

Ligand Effects in SCILL Model Systems: Site‐Specific Interactions with Pt and Pd Nanoparticles

Infrared Study of Benzene Hydrogenation on Pt/SiO2 Catalyst by Co-adsorption of CO and Benzene

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