Steps and catalytic reactions: CO oxidation with preadsorbed O on Rh(553)

Zhang, Chu; Wang, Baochang; Hellman, Anders; Shipilin, Mikhail; Schaëfer, Andreas; Merte, Lindsay R.; Blomberg, Sara; Wang, Xueting; Carlsson, Per; Lundgren, Edvin; Weissenrieder, Jonas; Resta, Andrea; Mikkelsen, Anders; Andersen, Jesper N; Gustafson, Johan

doi:10.1016/j.susc.2021.121928

Cited by 3 publications

(3 citation statements)

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“…We assign them to CO adsorbed in top (T T , 532.4 and 286.1 eV) and hollow (T H , 530.8 and 285.5 eV) terrace sites, respectively. 14,15,39 The intensity ratio T H /T T is close to 2, pointing toward the arrangement of the CO molecules in the (2 × 2)-3CO superstructure, with 0.75 ML (ML = monolayer, adsorbed molecules per substrate atom). 14−16 In the stepped (553) and (223) (top and bottom rows of Figure 2a, respectively), two more features are resolved in the C 1s region.…”

Section: ■ Resultsmentioning

confidence: 76%

“…At the (111) plane, two well-resolved peaks are observed in both the O 1s and C 1s core level regions. We assign them to CO adsorbed in top (T T , 532.4 and 286.1 eV) and hollow (T H , 530.8 and 285.5 eV) terrace sites, respectively. ,, The intensity ratio T H /T T is close to 2, pointing toward the arrangement of the CO molecules in the (2 × 2)-3CO superstructure, with 0.75 ML (ML = monolayer, adsorbed molecules per substrate atom). − In the stepped (553) and (223) (top and bottom rows of Figure a, respectively), two more features are resolved in the C 1s region. They correspond to CO molecules adsorbed in top (S T , 285.8 eV) and bridge (S B 285.4 eV) positions at steps, and as previously reported they equally cover the surface .…”

Section: Resultsmentioning

confidence: 99%

“…This is explained by considering a transition of some CO molecules from T H to T T sites, as T H -CO is known to become less favorable as the step density increases and the terraces narrow. 40 Step-related CO contributions cannot be resolved in the O 1s region, 39 hence the peaks are renamed as (S B + T H ) and (S T + T T ). The CO (g) emission peaks at 536.5 eV.…”

Section: ■ Resultsmentioning

confidence: 99%

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Structure Matters: Asymmetric CO Oxidation at Rh Steps with Different Atomic Packing

et al. 2022

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Curved crystals are a simple but powerful approach to bridge the gap between single crystal surfaces and nanoparticle catalysts, by allowing a rational assessment of the role of active step sites in gas-surface reactions. Using a curved Rh(111) crystal, here, we investigate the effect of A-type (square geometry) and B-type (triangular geometry) atomic packing of steps on the catalytic CO oxidation on Rh at millibar pressures. Imaging the crystal during reaction ignition with laser-induced CO2 fluorescence demonstrates a two-step process, where B-steps ignite at lower temperature than A-steps. Such fundamental dissimilarity is explained in ambient pressure X-ray photoemission (AP-XPS) experiments, which reveal partial CO desorption and oxygen buildup only at B-steps. AP-XPS also proves that A-B step asymmetries extend to the active stage: at A-steps, low-active O–Rh–O trilayers buildup immediately after ignition, while highly active chemisorbed O is the dominant species on B-type steps. We conclude that B-steps are more efficient than A-steps for the CO oxidation.

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Section: ■ Resultsmentioning

confidence: 76%