Reactivity of FeO(111)/Pt(111) with Alcohols

Kim, Yu Kwon; Zhang, Zhenrong; Parkinson, Gareth S.; Li, Shao‐Chun; Kay, Bruce D.; Dohnálek, Zdenek

doi:10.1021/jp907844j

Cited by 19 publications

(20 citation statements)

References 47 publications

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“…Such character has also been used to distinguish molecular or dissociated alcohol species previously23. The facile deprotonation of alcohols on FeO/Pt(111) has been shown in IRAS and TPD studies by Kim et al 24. A broad water desorption peak at between 200 and 400 K, indicating the facile deprotonation of alcohols, was observed, which does not occur on Pt(111).…”

Section: Resultsmentioning

confidence: 95%

Metal/oxide interfacial effects on the selective oxidation of primary alcohols

et al. 2017

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A main obstacle in the rational development of heterogeneous catalysts is the difficulty in identifying active sites. Here we show metal/oxide interfacial sites are highly active for the oxidation of benzyl alcohol and other industrially important primary alcohols on a range of metals and oxides combinations. Scanning tunnelling microscopy together with density functional theory calculations on FeO/Pt(111) reveals that benzyl alcohol enriches preferentially at the oxygen-terminated FeO/Pt(111) interface and undergoes readily O-H and C-H dissociations with the aid of interfacial oxygen, which is also validated in the model study of Cu 2 O/Ag(111). We demonstrate that the interfacial effects are independent of metal or oxide sizes and the way by which the interfaces were constructed. It inspires us to inversely support nano-oxides on micro-metals to make the structure more stable against sintering while the number of active sites is not sacrificed. The catalyst lifetime, by taking the inverse design, is thereby significantly prolonged.

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Section: Resultsmentioning

confidence: 95%

Metal/oxide interfacial effects on the selective oxidation of primary alcohols

et al. 2017

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“…53,[55][56][57][58] In contrast, Fe 3 O 4 (001) is a flat surface, as is the only other metal-oxide surface where zero-order kinetics has been observed to date: the ultrathin FeO(111) film grown on Pt(111). 21,22,59,60 For coverages up to 0.5 molecule per (…”

Section: Discussionmentioning

confidence: 99%

“…It is not straightforward to achieve reproducible thermal contact and temperature measurement on such samples, and we followed the approach described in the work of Kay et al [21][22][23] and Kimmel et al 24,25 The metal oxide sample is mounted on a metal backplate, and the temperature is measured by K-type thermocouple spot-welded to the backplate. The temperature at the sample surface is calibrated by multilayer desorption, as described by Schlichting and Menzel.…”

Section: A Tpd Of Metal-oxide Single Crystalsmentioning

confidence: 99%

A multi-technique study of CO2 adsorption on Fe3O4 magnetite

Pavelec

Hulva

Halwidl

et al. 2017

The Journal of Chemical Physics

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The adsorption of CO 2 on the Fe 3 O 4 (001)-( √ 2 × √ 2)R45 • surface was studied experimentally using temperature programmed desorption (TPD), photoelectron spectroscopies (UPS and XPS), and scanning tunneling microscopy. CO 2 binds most strongly at defects related to Fe 2+ , including antiphase domain boundaries in the surface reconstruction and above incorporated Fe interstitials. At higher coverages, CO 2 adsorbs at fivefold-coordinated Fe 3+ sites with a binding energy of 0.4 eV. Above a coverage of 4 molecules per (• unit cell, further adsorption results in a compression of the first monolayer up to a density approaching that of a CO 2 ice layer. Surprisingly, desorption of the second monolayer occurs at a lower temperature (≈84 K) than CO 2 multilayers (≈88 K), suggestive of a metastable phase or diffusion-limited island growth. The paper also discusses design considerations for a vacuum system optimized to study the surface chemistry of metal oxide single crystals, including the calibration and characterisation of a molecular beam source for quantitative TPD mea-

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“…Indeed, the O-terminated FeO(111) bi-layer film is particularly inert [303; 375-380] because undercoordinated cations/anion pairs are generally required for dissociative adsorption on metal oxide surfaces [381; 382]. However, the thin film can be reduced through exposure to H and alcohols via a Mars-van Krevelen mechanism at elevated temperature [383][384][385], with undercoordinated Fe dissolving into the Pt crystal.…”

Section: Wüstite (Fe 1-x O) Surfacesmentioning

confidence: 99%

Iron oxide surfaces

Parkinson

2016

Surface Science Reports

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482

463

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The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe 3 O 4 ), maghemite (γ-Fe 2 O 3 ), hematite (α-Fe 2 O 3 ), and wüstite (Fe 1-x O) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe 3 O 4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment, and because it is an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed.The best understood iron oxide surface at present is probably Fe 3 O 4 (100); the structure is known with a high degree of precision and the major defects and properties are well characterised. A major factor in this is that a termination at the Fe oct -O plane can be reproducibly prepared by a variety of methods, as long as the surface is annealed in 10 Such straightforward preparation of a monophase termination is generally not the case for other iron oxide surfaces. All available evidence suggests the oft-studied (√2×√2)R45° reconstruction results from a rearrangement of the cation lattice in the outermost unit cell in which two octahedral cations are replaced by one tetrahedral interstitial, a motif conceptually similar to well-known Koch-Cohen defects in Fe (0001) is the most studied hematite surface, but 2 difficulties preparing stoichiometric surfaces under UHV conditions have hampered a definitive determination of the structure. There is evidence for at least three terminations: a bulk-like termination at the oxygen plane, a termination with half of the cation layer, and a termination with ferryl groups. When the surface is reduced the so-called "bi-phase" structure is formed, which eventually transforms to a Fe 3 O 4 (111)-like termination. The structure of the bi-phase surface is controversial; a largely accepted model of coexisting Fe 1-x O and α-Fe 2 O 3 (0001) islands was recently challenged and a new structure based on a thin film of Fe 3 O 4 (111) on α-Fe 2 O 3 (0001) was proposed. The merits of the compet...

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Reactivity of FeO(111)/Pt(111) with Alcohols

Cited by 19 publications

References 47 publications

Metal/oxide interfacial effects on the selective oxidation of primary alcohols

Metal/oxide interfacial effects on the selective oxidation of primary alcohols

A multi-technique study of CO2 adsorption on Fe3O4 magnetite

Iron oxide surfaces

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