Adsorption and Reaction of CO and NO on Ir(111) Under Near Ambient Pressure Conditions

Ueda, Kohei; Suzuki, Kazuhiro; Toyoshima, Ryo; Monya, Yuji; Yoshida, Masaaki; Isegawa, Kazuhisa; Amemiya, Kenta; Mase, Kenji; Mun, Bongjin Simon; Arman, Mohammad A.; Grånäs, Elin; Knudsen, Jan; Schnadt, Joachim; Kondoh, Hiroshi

doi:10.1007/s11244-015-0523-5

Cited by 20 publications

(40 citation statements)

References 36 publications

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“…New components N A and B A also emerge at lower binding energy with respect to the main peaks. Consistent with literature, we attribute this intensity to atomic species [21,24,78] detached by energetic collisions from the network, but still bound to the Ir substrate. It is obvious from the spectra in Fig.…”

Section: X-ray Photoelectron Spectroscopysupporting

confidence: 89%

Annealing of ion-irradiated hexagonal boron nitride on Ir(111)

et al. 2017

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Annealing of a monolayer of hexagonal boron nitride destroyed by Xe ion irradiation gives rise to rich structural phenomena investigated here through a combination of scanning tunneling microscopy, low-energy electron diffraction, x-ray photoelectron spectroscopy, and density functional theory calculations. We find selective pinning of vacancy clusters at a single specific location within the moiré formed by hexagonal boron nitride (h-BN) and the Ir substrate, crystalline Xe at room temperature of monolayer and bilayer thickness sealed inside h-BN blisters, standalone blisters only bound to the metal at temperatures where boron nitride on Ir (111) decomposes, and finally a pronounced threefold symmetry of all morphological features due to the preferential formation of boron-terminated zigzag edges that firmly bind to the substrate. The investigations give clear insight into the relevance of the substrate for the damage creation and annealing in a two-dimensional layer material.

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Section: X-ray Photoelectron Spectroscopysupporting

confidence: 89%

Annealing of ion-irradiated hexagonal boron nitride on Ir(111)

et al. 2017

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“…Therefore, these spectral features can be assigned to metallic Ir or to Ir cus sites with formal oxidation states of 0 and +3 1/3, respectively, and are in agreement with a previous assignment based on DFT calculations. 22,38,39 The pair of peaks at 62.5 eV/66.1 eV is ascribed to an Ir species with a higher oxidation state than +4 such as the Ir cus −O ot species. Assuming that O is always in the oxidation state −2, Ir cus in Ir cus −O ot would formally be in the oxidation state +5 1/3.…”

Section: Resultsmentioning

confidence: 99%

Thermal Stability of Single-Crystalline IrO₂(110) Layers: Spectroscopic and Adsorption Studies

et al. 2020

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The interaction of ultrathin single-crystalline IrO 2 (110) films with the gas phase proceeds via the coordinatively unsaturated sites (cus), in particular Ir cus , the undercoordinated oxygen species on-top O (O ot ) that are coordinated to Ir cus , and bridging O (O br ). With the combination of different experimental techniques, such as thermal desorption spectroscopy, scanning tunneling microscopy (STM), high-resolution core-level spectroscopy (HRCLS), infrared spectroscopy, and first-principles studies employing density functional theory calculations, we are able to elucidate surface properties of single-crystalline IrO 2 (110). We provide spectroscopic fingerprints of the active surface sites of IrO 2 (110). The freshly prepared IrO 2 (110) surface is virtually inactive toward gas-phase molecules. The IrO 2 (110) surface needs to be activated by annealing to 500−600 K under ultrahigh vacuum (UHV) conditions. In the activation step, Ir cus sites are liberated from on-top oxygen (O ot ) and monoatomic Ir metal islands are formed on the surface, leading to the formation of a bifunctional model catalyst. Vacant Ir cus sites of IrO 2 (110) allow for strong interaction and accommodation of molecules from the gas phase. For instance, CO can adsorb atop on Ir cus and water forms a strongly bound water layer on the activated IrO 2 (110) surface. Single-crystalline IrO 2 (110) is thermally not very stable although chemically stable. Chemical reduction of IrO 2 (110) by extensive CO exposure at 473 K is not observed, which is in contrast to the prototypical RuO 2 (110) system.

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“…It was originally proposed that CO molecules can adsorb on both on top and bridge sites on Ir(111) single crystal surface. A recent study suggests an exclusive occupation of top sites even at higher CO coverages 21,22 . Schick et al reported a single absorption IR band at about 2090 cm -1 for CO adsorbed in on top sites on Ir(111), which desorbs between 400 and 600 K 23 .…”

Section: Introductionmentioning

confidence: 93%

“…For the lowest investigated CO coverage (0.33 ML), the adsorbates form a (√3x√3)R30° superstructure (Fig. 9 a), where the When the CO coverage is increased, a (2√3x2√3)R30° superstructure is formed with a coverage of 7/12 (= 0.58) ML 22 . Again all CO molecules are predicted to adsorb at on top sites (see Fig.…”

Section: Dft Calculations For Single Crystal Ir(111) Surface and One mentioning

confidence: 99%

Monitoring the Interaction of CO with Graphene Supported Ir Clusters by Vibrational Spectroscopy and Density Functional Theory Calculations

et al. 2018

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The interaction of carbon monoxide (CO) with graphene supported Ir cluster (Ir/graphene/Ir(111)) and a Ir(111) single crystal surface was studied by infrared reflection–adsorption spectroscopy (IRRAS). The cluster morphology was characterized by scanning tunneling microscopy and density functional theory (DFT) calculations predicted the adsorption frequencies of CO molecules on the Ir single crystal surface and clusters. After exposing the clean Ir(111) surface to CO at 195 K, one intense vibrational band is observed at 2043 cm–1, which is assigned to on top CO species. This band shifts to a much higher frequency at 2082 cm–1 at higher CO exposure. After exposing clean graphene/Ir(111) to CO at 195 K, no CO band was observed in the IR spectra, which confirms a full graphene layer over the Ir(111) surface. However, CO molecules adsorb on Ir clusters supported on graphene/Ir(111) at 195 K. For the 0.05, 0.1, 0.15, and 0.2 ML Ir clusters, two IR bands were observed at 2060 and 2088 cm–1, 2050 and 2070 cm–1, 2048 and 2070 cm–1, and 2052 and 2070 cm–1, respectively. The IR bands at lower frequencies are assigned to the CO on one-layer high clusters, and the IR bands at higher frequencies are assigned to the CO adsorption on two- or several-layer high clusters. The IR frequencies of CO adsorbed on clusters are shifted to lower wavenumbers compared to those observed on the single crystal surface, which is in agreement with DFT calculations. The IRRAS data recorded after CO adsorption on Ir clusters at different temperatures demonstrate that CO species are stable up to 350 K, although the intensity of CO on top one-layer high cluster reduces largely, indicating CO-induced cluster sintering.

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Adsorption and Reaction of CO and NO on Ir(111) Under Near Ambient Pressure Conditions

Cited by 20 publications

References 36 publications

Annealing of ion-irradiated hexagonal boron nitride on Ir(111)

Annealing of ion-irradiated hexagonal boron nitride on Ir(111)

Thermal Stability of Single-Crystalline IrO₂(110) Layers: Spectroscopic and Adsorption Studies

Monitoring the Interaction of CO with Graphene Supported Ir Clusters by Vibrational Spectroscopy and Density Functional Theory Calculations

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Adsorption and Reaction of CO and NO on Ir(111) Under Near Ambient Pressure Conditions

Cited by 20 publications

References 36 publications

Annealing of ion-irradiated hexagonal boron nitride on Ir(111)

Annealing of ion-irradiated hexagonal boron nitride on Ir(111)

Thermal Stability of Single-Crystalline IrO2(110) Layers: Spectroscopic and Adsorption Studies

Monitoring the Interaction of CO with Graphene Supported Ir Clusters by Vibrational Spectroscopy and Density Functional Theory Calculations

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Product

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Thermal Stability of Single-Crystalline IrO₂(110) Layers: Spectroscopic and Adsorption Studies