Reaction-path switching induced by spatial-distribution change of reactants: CO oxidation on Pt(111)

Nakai, Ikuyo; Kondoh, Hiroshi; Amemiya, Kenta; Nagasaka, Masanari; Nambu, Akira; Shimada, Toru; Ohta, Toshiaki

doi:10.1063/1.1796235

Cited by 39 publications

(22 citation statements)

References 24 publications

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“…Thus, CO oxidation, often quoted as a textbook example of catalytic reaction, is one of the best-known heterogeneous reactions and can be regarded as a benchmark system [1]. Though earlier studies have shown that some noble metals, such as Pd [2][3][4][5][6][7][8], Pt [3,[6][7][8][9][10][11][12][13], Rh [3,[6][7][8][9][14][15][16][17], and Au [18][19][20][21][22], can effectively catalyze CO oxidation, the high cost and high reaction temperature for efficient operations impose great limitations to the potential applications of these noble metal catalysts as good catalysts for CO oxidation. Therefore, it is understandable that scientists have been continuously endeavoring to seek suitable catalysts with high activity and lower cost to realize the low-temperature oxidation of CO.…”

Section: Introductionmentioning

confidence: 98%

Si-embedded graphene: an efficient and metal-free catalyst for CO oxidation by N2O or O2

Zhao

Chen

2012

Theor Chem Acc

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As is well known, searching for an efficient catalyst for CO oxidation is of great importance in the removal of poisonous CO gas. From the results of density functional theory calculations, we have reported the catalytic oxidation of CO by O 2 or N 2 O on Si-embedded graphene. Both Langmuir-Hinshelwood and Eley-Rideal mechanisms of CO oxidation on Si-embedded graphene were comparably studied. The results indicate that CO oxidation by O 2 on Si-embedded can occur via a two-step mechanism: (1) CO ? O 2 ? OOCO ? CO 2 ? O, followed by (2) CO ? O ? CO 2 . The energy barriers for the two steps are 0.48 and 0.57 eV, respectively. For N 2 O ? CO ? N 2 ? CO 2 , N 2 O firstly interacts with Si-embedded graphene, releasing N 2 and leaving the O-atom to be attacked by the subsequent CO to yield CO 2 to proceed with the catalytic cycle. The present results provide a useful guidance to fabricate metal-free graphene-based catalysts for CO oxidation with low cost and high activity.

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Section: Introductionmentioning

confidence: 98%

Si-embedded graphene: an efficient and metal-free catalyst for CO oxidation by N2O or O2

Zhao

Chen

2012

Theor Chem Acc

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“…[14,24,[29][30] In addition to E ad , the energy barrier E b is another essential parameter to describe the rate of a reaction. Earlier attempts, both experimentally [23,25,[31][32][33][34] and theoretically, [25,[35][36][37][38][39] have been made to lower the E b values for CO oxidation on metallic surfaces. In contrast, recent studies address novel catalysts such as alloys, [40][41][42] clusters, [1,40,[43][44][45] and even metallic nanotubes.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of CO Catalyzed by a Cu Cluster: Influence of an Electric Field

et al. 2009

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Adsorption ability and reaction rate are two essential parameters that define the efficiency of a catalyst. Herein, we implement density functional theory (DFT) and report that CO can be oxidized by a pyramidal Cu cluster with an associated reaction barrier E(b)=1.317 eV. In this case, our transition state calculations reveal that the barrier can be significantly lowered after superimposing a negative electric field. Moreover, when the field intensity corresponds to F=-0.010 au, the magnitude of E(b)=0.698 eV is equivalent to-or lower than-those of typical catalysts such as Pt, Rh, and Pd. The superimposition of a positive field is found to enhance the release of the nascent CO(2) molecule. Our study demonstrates that small Cu clusters have better adsorption ability than the corresponding flat surface while the field can be used to enhance the purification of the exhaust gas.

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“…CO oxidation over Pt has been widely studied by dosing or impinging CO over the oxygenprecovered surface mostly under UHV conditions to elucidate transient species during the reaction. 16,19,20,[23][24][25][26]41 Some studies analyzed CO 2 formation 23,25 and others assumed fast formation and desorption of CO 2 from Pt surfaces. 19,24 The assumption of fast CO 2 desorption is reasonable when dosing CO over an oxygen-covered Pt surface due to the stronger adsorption of CO on Pt compared with CO 2 and oxygen.…”

Section: Reaction Mechanism and Possible Surface Speciesmentioning

confidence: 99%

“…16 Bridging the pressure gap by theoretical means was also attempted and the higher reactivity of such an oxide phase compared with that of a Pt surface was shown. 17 Various surface-sensitive techniques have been used under UHV conditions, [18][19][20][21][22] but only a few techniques could be applied under relatively high pressures. Among surface-sensitive vibrational spectroscopies, IRRAS has been used to study CO oxidation over Pt at low pressures [23][24][25][26] except one study under a high oxygen pressure ͑ca.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous in situ monitoring of surface and gas species and surface properties by modulation excitation polarization-modulation infrared reflection-absorption spectroscopy: CO oxidation over Pt film

Urakawa

Bürgi

Schläpfer

et al. 2006

The Journal of Chemical Physics

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A method for in situ monitoring of surface and gas species utilizing separately the difference and sum reflectivity of two polarizations, normal and parallel to the surface, measured by polarization-modulation infrared reflection-absorption spectroscopy is presented. Surface and gas-phase spectra were separately but simultaneously obtained from the reflectivities. The technique is combined with modulation excitation spectroscopy to further enhance the sensitivity, and a small-volume cell was designed for this purpose. CO oxidation over a 40 nm Pt film on aluminum was investigated under moderate pressure ͑atmospheric pressure, 5% CO, and 5%-40% O 2 ͒ at 373-433 K. The surface species involved in the oxidation process and the gas-phase species, both reactant ͑CO͒ and product ͑CO 2 ͒, could be simultaneously monitored and analyzed quantitatively. In addition, the reflectivity change of the sample during the reaction was assigned to a near-surface bulk property change, that is, surface reconstruction to the oxide phase. Under an O 2 -rich atmosphere, two reactive phases, denoted as low-and high-activity phases, were identified. A large amount of atop CO was observed during the low-activity phase, while the adsorbed CO completely disappeared during the high-activity phase. The presence of an infrared-inactive CO 2 precursor formed by the reaction between surface oxide and gaseous CO during the high-activity phase was inferred. The desorption of the CO 2 precursor is facilitated under a CO-rich atmosphere, most likely, by surface reconstruction to metallic Pt and a competitive adsorption of CO on the surface.

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Reaction-path switching induced by spatial-distribution change of reactants: CO oxidation on Pt(111)

Cited by 39 publications

References 24 publications

Si-embedded graphene: an efficient and metal-free catalyst for CO oxidation by N2O or O2

Si-embedded graphene: an efficient and metal-free catalyst for CO oxidation by N2O or O2

Oxidation of CO Catalyzed by a Cu Cluster: Influence of an Electric Field

Simultaneous in situ monitoring of surface and gas species and surface properties by modulation excitation polarization-modulation infrared reflection-absorption spectroscopy: CO oxidation over Pt film

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