CO adsorption site occupation on Pt(335): a quantitative investigation using TPD and EELS

CO monolayer oxidation at Pt(100) probed by potential step measurements in comparison to Pt(111) and Pt nanoparticle catalyst

“…7, the first component peak may reflect responses for the fast reacting population of CO ads on terraces and the second component may be associated with the slower reacting step-CO ads molecules. Infrared spectroscopy measurements have revealed surfaces of Pt(s)-[n(1 1 1) Â (1 0 0)] type single crystals show a well defined transition in CO adlayer properties between low coverage states, where CO is bound exclusively at step sites, and higher coverage states in which CO molecules are bound to both steps and terraces [22,23,48,[53][54][55]. The component peaks in Fig.…”

The dissimilar twins – a comparative, site-selective in situ study of CO adsorption and desorption on Pt(322) and Pt(355)

“…However, in literature the on-top site is most favored for stepped platinum surfaces with (1 1 1) steps, e.g., as found on Pt(3 3 2) by high-resolution electron energy loss spectroscopy (HREELS) [11], whereas for (1 0 0) steps both on-top and bridge sites have been proposed [8][9][10]26]. Therefore, we assign the C 1s peaks at 286.43 eV on Pt(3 2 2) and Pt (3 5 5) to CO at step on-top sites, and the peak at 285.83 on Pt(3 2 2) to CO at step bridge sites.…”

“…In early work on Pt(3 3 5) (denoted Pt(5 3 3) in the original literature, but changed for easier comparison within this work), Hayden et al [8] and also Lambert and Tobin [9] found no occupation of bridge sites. On the other hand, in a combined TPD/HREELS (high-resolution electron energy loss spectroscopy) study on the same system, Luo et al [10] report CO also at terrace bridge sites and for very low coverage (h < 0.12 ML) also at step bridge sites. For intermediate coverages (0.22 < h < 0.42 ML), the latter are displaced from step bridge sites to adjacent step ontop sites.…”

“…Only for Pt(1 1 2), a surface with (1 1 1) terraces and (1 0 0) steps, coveragedependent ordered adsorbate structures have been observed by LEED [14]. Therefore, most of the structural models proposed so far are just based on spectroscopic information [10,15,16]. For Pt (3 3 5), geometric models have been tested by comparison of simulated vibrational spectra using site-specific coupled harmonic oscillators with experimental results [15].…”

Active site model for CO adlayer electrooxidation on nanoparticle catalysts

“…A vast number of studies have been undertaken in order to elucidate the effects of particle size and morphology for CO ad electrooxidation, exploring the favourable catalyst surface morphology and the pertinent reaction mechanisms [17][18][19][20][21][22][23][24][25][26][27]. Studies on well-defined single crystalline surfaces indicate that CO ad electrooxidation is predominantly activated at step sites and that CO ad surface mobility is not a limiting process [25,26].…”