On the deactivation of Mo/HZSM-5 in methane dehydroaromatization (2024)

Tempelman, C. H. L. (2015). On the deactivation of Mo/HZSM-5 in methane dehydroaromatization. Applied Catalysis. B, Environmental, 176, 731-739. https://doi.org/10.1016/j.apcatb.2015.04.052

Tempelman, C.H.L. ; Hensen, E.J.M. / On the deactivation of Mo/HZSM-5 in methane dehydroaromatization. In: Applied Catalysis. B, Environmental. 2015 ; Vol. 176. pp. 731-739.

@article{81998ef4d3a14fa38eb9b70974141436,

title = "On the deactivation of Mo/HZSM-5 in methane dehydroaromatization",

abstract = "The deactivation of Mo/HZSM-5 during the non-oxidative methane aromatization (MDA) reaction that yields benzene and hydrogen was investigated. Catalysts were recovered from the reactor after pre-activation and after increasing time on stream in methane. The physico-chemical properties of the spent catalysts were characterized in detail by Ar physisorption, 27Al MAS NMR and X-ray photoelectron spectroscopy. The nature of the carbon deposits was determined by UV Raman spectroscopy and TGA, and the size and location of the Mo-carbide particles by TEM and STEM-HAADF. The results show that the main cause for catalyst deactivation is the formation of a carbonaceous layer at the external zeolite surface. This layer is made up from polyaromatic hydrocarbons and decreases the accessibility of the Br{\o}nsted acid sites in the micropores. At the same time, the decreased interaction of the Mo-carbide particles with the external zeolite surface results in their sintering. The lower Mo-carbide dispersion decreases methane conversion rates. The decreased accessibility of the Br{\o}nsted acid sites shifts the selectivity from benzene to unsaturated intermediates formed on the Mo-carbide particles. Silylation of the external surface mainly results in lower rate of co*ke formation at the external surface, slowing down catalyst deactivation",

author = "C.H.L. Tempelman and E.J.M. Hensen",

year = "2015",

doi = "10.1016/j.apcatb.2015.04.052",

language = "English",

volume = "176",

pages = "731--739",

journal = "Applied Catalysis. B, Environmental",

issn = "0926-3373",

publisher = "Elsevier",

}

Tempelman, CHL 2015, 'On the deactivation of Mo/HZSM-5 in methane dehydroaromatization', Applied Catalysis. B, Environmental, vol. 176, pp. 731-739. https://doi.org/10.1016/j.apcatb.2015.04.052

On the deactivation of Mo/HZSM-5 in methane dehydroaromatization. / Tempelman, C.H.L.; Hensen, E.J.M.
In: Applied Catalysis. B, Environmental, Vol. 176, 2015, p. 731-739.

Research output: Contribution to journal › Article › Academic › peer-review

TY - JOUR

T1 - On the deactivation of Mo/HZSM-5 in methane dehydroaromatization

AU - Tempelman, C.H.L.

AU - Hensen, E.J.M.

PY - 2015

Y1 - 2015

N2 - The deactivation of Mo/HZSM-5 during the non-oxidative methane aromatization (MDA) reaction that yields benzene and hydrogen was investigated. Catalysts were recovered from the reactor after pre-activation and after increasing time on stream in methane. The physico-chemical properties of the spent catalysts were characterized in detail by Ar physisorption, 27Al MAS NMR and X-ray photoelectron spectroscopy. The nature of the carbon deposits was determined by UV Raman spectroscopy and TGA, and the size and location of the Mo-carbide particles by TEM and STEM-HAADF. The results show that the main cause for catalyst deactivation is the formation of a carbonaceous layer at the external zeolite surface. This layer is made up from polyaromatic hydrocarbons and decreases the accessibility of the Brønsted acid sites in the micropores. At the same time, the decreased interaction of the Mo-carbide particles with the external zeolite surface results in their sintering. The lower Mo-carbide dispersion decreases methane conversion rates. The decreased accessibility of the Brønsted acid sites shifts the selectivity from benzene to unsaturated intermediates formed on the Mo-carbide particles. Silylation of the external surface mainly results in lower rate of co*ke formation at the external surface, slowing down catalyst deactivation

AB - The deactivation of Mo/HZSM-5 during the non-oxidative methane aromatization (MDA) reaction that yields benzene and hydrogen was investigated. Catalysts were recovered from the reactor after pre-activation and after increasing time on stream in methane. The physico-chemical properties of the spent catalysts were characterized in detail by Ar physisorption, 27Al MAS NMR and X-ray photoelectron spectroscopy. The nature of the carbon deposits was determined by UV Raman spectroscopy and TGA, and the size and location of the Mo-carbide particles by TEM and STEM-HAADF. The results show that the main cause for catalyst deactivation is the formation of a carbonaceous layer at the external zeolite surface. This layer is made up from polyaromatic hydrocarbons and decreases the accessibility of the Brønsted acid sites in the micropores. At the same time, the decreased interaction of the Mo-carbide particles with the external zeolite surface results in their sintering. The lower Mo-carbide dispersion decreases methane conversion rates. The decreased accessibility of the Brønsted acid sites shifts the selectivity from benzene to unsaturated intermediates formed on the Mo-carbide particles. Silylation of the external surface mainly results in lower rate of co*ke formation at the external surface, slowing down catalyst deactivation

U2 - 10.1016/j.apcatb.2015.04.052

DO - 10.1016/j.apcatb.2015.04.052

M3 - Article

SN - 0926-3373

VL - 176

SP - 731

EP - 739

JO - Applied Catalysis. B, Environmental

JF - Applied Catalysis. B, Environmental

ER -

Tempelman CHL, Hensen EJM. On the deactivation of Mo/HZSM-5 in methane dehydroaromatization. Applied Catalysis. B, Environmental. 2015;176:731-739. doi: 10.1016/j.apcatb.2015.04.052