TY - JOUR

T1 - NAP-XPS and in situ XRD study of the stability of Bi-modified MoVNbTeO catalysts for oxidative dehydrogenation of ethane

AU - Svintsitskiy, Dmitry A.

AU - Kardash, Tatyana Yu

AU - Lazareva, Evgeniya V.

AU - Saraev, Andrey A.

AU - Derevyannikova, Elizaveta A.

AU - Vorokhta, Mykhailo

AU - Šmíd, Břetislav

AU - Bondareva, Valentina M.

N1 - Publisher Copyright: © 2019 Elsevier B.V.

PY - 2019/6/5

Y1 - 2019/6/5

N2 - This work presents the investigation of Bi-modified MoVNbTeO catalysts for oxidative dehydrogenation of ethane (ODE) using the combination of NAP-XPS, in situ XRD and XANES/EXAFS techniques. It was found that introduction of Bi improves the tolerance of catalysts toward severe reaction conditions (high temperature and/or enhanced ethane/oxygen ratio) resulting in a significant decrease in the degree of deactivation. In accordance with NAP-XPS data, the surface/subsurface Te concentration was maintained for Bi-containing MoVNbTeO catalysts even after treatment with a reducing reaction mixture (C 2 H 6 /O 2 >3) at temperatures up to 460 °C. In the case of the unmodified catalyst, such treatment resulted in the surface/subsurface depletion of Te due to the reduction into the Te° state followed by its sublimation into the gas phase. The incorporation of Bi within extended six-membered channels of the M1 structure was suggested based on XANES/EXAFS data. Such incorporation probably influences the mobility of Te within channels, resulting in the limitation of Te diffusion from the particle bulk to the surface. The improved tolerance of catalytically active M1 phase toward severe reaction conditions was confirmed by in situ XRD data during heating in a mixture of 8 wt % C 2 H 6 /He.

AB - This work presents the investigation of Bi-modified MoVNbTeO catalysts for oxidative dehydrogenation of ethane (ODE) using the combination of NAP-XPS, in situ XRD and XANES/EXAFS techniques. It was found that introduction of Bi improves the tolerance of catalysts toward severe reaction conditions (high temperature and/or enhanced ethane/oxygen ratio) resulting in a significant decrease in the degree of deactivation. In accordance with NAP-XPS data, the surface/subsurface Te concentration was maintained for Bi-containing MoVNbTeO catalysts even after treatment with a reducing reaction mixture (C 2 H 6 /O 2 >3) at temperatures up to 460 °C. In the case of the unmodified catalyst, such treatment resulted in the surface/subsurface depletion of Te due to the reduction into the Te° state followed by its sublimation into the gas phase. The incorporation of Bi within extended six-membered channels of the M1 structure was suggested based on XANES/EXAFS data. Such incorporation probably influences the mobility of Te within channels, resulting in the limitation of Te diffusion from the particle bulk to the surface. The improved tolerance of catalytically active M1 phase toward severe reaction conditions was confirmed by in situ XRD data during heating in a mixture of 8 wt % C 2 H 6 /He.

KW - Bismuth

KW - Catalyst modification

KW - EXAFS

KW - In situ

KW - M1 phase

KW - MoVNbTe

KW - NAP-XPS

KW - ODE

KW - Oxidative dehydrogenation of ethane

KW - Six-membered channel

KW - Slurry method

KW - Tellurium

KW - SELECTIVE OXIDATION

KW - M2 PHASES

KW - CRYSTAL-STRUCTURE

KW - ACTIVE-SITES

KW - HYDROTHERMAL SYNTHESIS

KW - LIGHT ALKANES

KW - MOVTE(SB)NBO M1 PHASE

KW - SURFACE DYNAMICS

KW - MOVTENB OXIDE CATALYSTS

KW - PROPANE OXIDATION

UR - http://www.scopus.com/inward/record.url?scp=85065018839&partnerID=8YFLogxK

U2 - 10.1016/j.apcata.2019.04.027

DO - 10.1016/j.apcata.2019.04.027

M3 - Article

AN - SCOPUS:85065018839

VL - 579

SP - 141

EP - 150

JO - Applied Catalysis A: General

JF - Applied Catalysis A: General

SN - 0926-860X

ER -