TY - JOUR

T1 - X-ray-induced transformations on the surface of MoVNbTe mixed oxide catalyst: An XPS study

AU - Svintsitskiy, D. A.

AU - Kardash, T. Yu

AU - Lazareva, E. V.

AU - Bondareva, V. M.

N1 - Funding Information: This work was supported by the Russian Science Foundation , grant 17-73-20073 . The studies were conducted using the equipment of the Center of Collective Use “National Center of Catalyst Research”. The authors thank Alexander Sergeevich Marchuk for the Rietveld analysis of X-ray difrraction data. Publisher Copyright: © 2020 Elsevier B.V. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2021/1/1

Y1 - 2021/1/1

N2 - MoVNbTe mixed oxide, which is used as a catalyst for the oxidative dehydrogenation of ethane, was investigated by the XPS technique during prolonged treatment with X-rays. This treatment caused a modification of the MoVNbTe oxide surface related to the reduction of V, Mo, and Te species. This behavior is supposed to be related to the interaction of oxide with secondary electrons emitted during X-ray absorption. Firstly, the reduction of Te4+ into Te0 species, accompanied by the removal of no more than ~ 5% of overall oxygen from the surface/subsurface region, was found during ~ 8.5 h under X-rays. After ~ 28 h of exposure, the significant surface restructuring resulted in a change in the relative amounts of V and Te. This was accompanied by a high degree of surface reduction and the appearance of V3+ species. Under X-rays, an abnormal broadening of Mo 3d spectral lines was observed in contrast to other photoelectron regions. The possible reasons for this phenomenon were discussed. The limit for the amount of lattice oxygen, which might be extracted with the preservation of the pristine surface structure of MoVNbTe oxide, was in the range from 5 to 7%.

AB - MoVNbTe mixed oxide, which is used as a catalyst for the oxidative dehydrogenation of ethane, was investigated by the XPS technique during prolonged treatment with X-rays. This treatment caused a modification of the MoVNbTe oxide surface related to the reduction of V, Mo, and Te species. This behavior is supposed to be related to the interaction of oxide with secondary electrons emitted during X-ray absorption. Firstly, the reduction of Te4+ into Te0 species, accompanied by the removal of no more than ~ 5% of overall oxygen from the surface/subsurface region, was found during ~ 8.5 h under X-rays. After ~ 28 h of exposure, the significant surface restructuring resulted in a change in the relative amounts of V and Te. This was accompanied by a high degree of surface reduction and the appearance of V3+ species. Under X-rays, an abnormal broadening of Mo 3d spectral lines was observed in contrast to other photoelectron regions. The possible reasons for this phenomenon were discussed. The limit for the amount of lattice oxygen, which might be extracted with the preservation of the pristine surface structure of MoVNbTe oxide, was in the range from 5 to 7%.

KW - Mixed oxide

KW - Molybdenum

KW - MoVNbTeO

KW - Photoelectron spectroscopy

KW - Tellurium

KW - X-ray-induced reduction

KW - ETHANE

KW - SELECTIVE OXIDATION

KW - PROPANE AMMOXIDATION

KW - M1 PHASE

KW - MOVTE(SB)NBO CATALYSTS

KW - DEHYDROGENATION

KW - LIGHT ALKANES

KW - MOVTENB OXIDE

KW - NB

KW - ACTIVE-CENTERS

UR - http://www.scopus.com/inward/record.url?scp=85090227150&partnerID=8YFLogxK

U2 - 10.1016/j.apsusc.2020.147676

DO - 10.1016/j.apsusc.2020.147676

M3 - Article

AN - SCOPUS:85090227150

VL - 535

JO - Applied Surface Science

JF - Applied Surface Science

SN - 0169-4332

M1 - 147676

ER -