Carbon monoxide dissociation to oxidation surface reaction pathway shift on Mo(110) upon alloying with boron

Тваури, И.В.; Khubezhov, Soslan A.; Demeev, Z S; Turiev, Anatolij M.; Tsidaeva, Natalia; Магкоев, Т. Т.

doi:10.1016/j.vacuum.2012.08.004

Cited by 7 publications

(6 citation statements)

References 11 publications

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“…At the same time, due to the specific electronic properties of half-filled d-band, and the excess of free charge in such a metal like Al, the d-sp hybridization would shift the center of the d-band down with respect to Fermi level, thus increasing its filling and, as a consequence, enhancing catalytic activity [ 9 ]. In line with this assumption are the previous results of increase in CO catalytic oxidation activity on Mo(110) upon alloying with boron, the element which is isoelectronic to Al [ 12 ].…”

Section: Introductionsupporting

confidence: 68%

Preparation of Aluminum–Molybdenum Alloy Thin Film Oxide and Study of Molecular CO + NO Conversion on Its Surface

et al. 2022

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Adsorption and interaction of carbon monoxide (CO) and nitric oxide (NO) molecules on the surface of bare Al-Mo(110) system and on that obtained by its in situ oxidation have been studied in ultra-high vacuum (base pressure: ca. 10−8 Pa) by means of Auger and X-ray photoelectron spectroscopy (AES, XPS), low energy electron diffraction (LEED), reflection–absorption infrared and thermal desorption spectroscopy (RAIRS, TDS), and by the work function measurements. In order to achieve the Al-Mo(110) alloy the thin aluminum film of a few monolayers thick was in situ deposited onto the Mo(110) crystal and then annealed at 800 K. As a result of Al atoms diffusion into the Mo(110) subsurface region and the chemical reaction, the surface alloy of a hexagonal atomic symmetry corresponding to Al2Mo alloy is formed. The feature of thus formed surface alloy regarding molecular adsorption is that, unlike the bare Mo(110) and Al(111) substrates, on which both CO and NO dissociate, adsorption on the alloy surface is non-dissociative. Moreover, adsorption of carbon monoxide dramatically changes the state of pre-adsorbed NO molecules, displacing them to higher-coordinated adsorption sites and simultaneously tilting their molecular axis closer to the surface plane. After annealing of this coadsorbed system up to 320 K the (CO + NO → CO2 + N) reaction takes place resulting in carbon dioxide desorption into the gas phase and nitriding of the substrate. Such an enhancement of catalytic activity of Mo(110) upon alloying with Al is attributed to surface reconstruction resulting in appearance of new adsorption/reaction centers at the Al/Mo interface (steric effect), as well as to the Mo d-band filling upon alloying (electronic effect). Catalytic activity mounts further when the Al-Mo(110) is in situ oxidized. The obtained Al-Mo(110)-O ternary system is a prototype of a metal/oxide model catalysts featuring the metal oxides and the metal/oxide perimeter interfaces as a the most active reaction sites. As such, this type of low-cost metal alloy oxide models precious metal containing catalysts and can be viewed as a potential substitute to them.

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Section: Introductionsupporting

confidence: 68%

Preparation of Aluminum–Molybdenum Alloy Thin Film Oxide and Study of Molecular CO + NO Conversion on Its Surface

et al. 2022

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“…In line with the trend of modification of metals with boron, Tvauri et al [ 7 ] by Surface Science techniques demonstrated that the alloying of Mo(110) substrate with boron dramatically shifts the CO dissociation pathway on bare Mo(110) to oxidation (CO + 1/2O 2 →CO 2 ) at the borided Mo(110). It is concluded that this is due to d-band filling of Mo upon alloying with boron via d←p hybridization on one hand, and reconstruction of the surface with exposing the newly formed active adsorption/reaction sites to the gas phase on the other.…”

Section: Introductionmentioning

confidence: 76%

“…A comparison of the boron LEIS intensities before (spectrum 2) and after (spectrum 3) annealing indicates that the fraction of B atoms remaining at the outermost layer of the system after annealing is about 1/3 of the monolayer concentration. As has been noted above, the obtained system corresponds to quite stable molybdenum boride [ 7 ].…”

Section: Resultsmentioning

confidence: 98%

“…In terms of catalytic performance, for instance, for carbon monoxide oxidation by molecular oxygen, this system is much more active, compared to bare Mo [ 7 ]. A further increase of catalytic activity of molybdenum boride is achieved when it is oxidized.…”

Section: Resultsmentioning

confidence: 99%

“…For a long time, boron-doped materials have attracted much attention in finding wide application in different fields of science and technology, such as material science, mechanical engineering, electronics, optics and others [ 1 , 2 , 3 ]. Quite recently, a new applied relevance was found as efficient materials for heterogeneous catalysis, often viewed as substitutes to precious metal-containing catalysts [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. This is due to quite unique transformation of the properties of one or another material upon doping with boron, such as surface atomic reconstruction accompanied by the creation of new active reaction sites, modification of the electron structure favoring adsorption and conversion of molecules and appearance of new reaction channels, etc.…”

Section: Introductionmentioning

confidence: 99%

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Enhancing the Catalytic Activity of Mo(110) Surface via Its Alloying with Submonolayer to Multilayer Boron Films and Oxidation of the Alloy: A Case of (CO + O2) to CO2 Conversion

Men

Магкоев

Behjatmanesh–Ardakani

et al. 2023

Nanomaterials

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In-situ formation of boron thin films on the Mo(110) surface, as well as the formation of the molybdenum boride and its oxide and the trends of carbon monoxide catalytic oxidation on the substrates formed, have been studied in an ultra-high vacuum (UHV) by a set of surface-sensitive characterization techniques: Auger and X-ray photoelectron spectroscopy (AES, XPS), low-energy ion scattering (LEIS), reflection-absorption infrared spectroscopy (RAIRS), temperature-programmed desorption (TPD), electron energy loss spectroscopy (EELS) and work function measurements using the Anderson method. The boron deposited at Mo(110) via electron-beam deposition at a substrate temperature of 300 K grows as a 2D layer, at least in submonolayer coverage. Such a film is bound to the Mo(110) via polarized chemisorption bonds, dramatically changing the charge density at the substrate surface manifested by the Mo(110) surface plasmon damping. Upon annealing of the B-Mo(110) system, the boron diffuses into the Mo(110) bulk following a two-mode regime: (1) quite easy dissolution, starting at a temperature of about 450 K with an activation energy of 0.4 eV; and (2) formation of molybdenum boride at a temperature higher than 700 K with M-B interatomic bonding energy of 3.8 eV. The feature of the formed molybdenum boride is that there is quite notable carbon monoxide oxidation activity on its surface. A further dramatic increase of such an activity is achieved when the molybdenum boride is oxidized. The latter is attributed to more activated states of molecular orbitals of coadsorbed carbon monoxide and oxygen due to their enhanced interaction with both boron and oxygen species for MoxByOz ternary compound, compared to only boron for the Mox’By’ double alloy.

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Reduction of nitric oxide with carbon monoxide on the Al–Mo(110) surface alloy

Grigorkina

Тваури

Kaloeva

et al. 2016

Solid State Communications

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Carbon monoxide dissociation to oxidation surface reaction pathway shift on Mo(110) upon alloying with boron

Cited by 7 publications

References 11 publications

Preparation of Aluminum–Molybdenum Alloy Thin Film Oxide and Study of Molecular CO + NO Conversion on Its Surface

Preparation of Aluminum–Molybdenum Alloy Thin Film Oxide and Study of Molecular CO + NO Conversion on Its Surface

Enhancing the Catalytic Activity of Mo(110) Surface via Its Alloying with Submonolayer to Multilayer Boron Films and Oxidation of the Alloy: A Case of (CO + O2) to CO2 Conversion

Reduction of nitric oxide with carbon monoxide on the Al–Mo(110) surface alloy

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