Stability of Pt/γ-Al2O3 catalysts in lignin and lignin model compound solutions under liquid phase reforming reaction conditions

A.L. Jongerius, J.R. Copeland, G.S. Foo, J.P. Hofmann, P.C.A. Bruijnincx, C. Sievers, B.M. Weckhuysen

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Abstract

The stability of a 1 wt % Pt/¿-Al2O3 catalyst was tested in an ethanol/water mixture at 225 °C and autogenic pressure, conditions at which it is possible to dissolve and depolymerize various kinds of lignin, and structural changes to the catalysts were studied by means of X-ray diffraction (XRD), 27Al MAS NMR, N2 physisorption, transmission electron microscopy (TEM), H2 chemisorption, elemental analysis, thermogravimetric analysis-mass spectrometry (TGA-MS), and IR. In the absence of reactants the alumina support is found to transform into boehmite within 4 h, leading to a reduction in support surface area, sintering of the supported Pt nanoparticles, and a reduction of active metal surface area. Addition of aromatic oxygenates to mimic the compounds typically obtained by lignin depolymerization leads to a slower transformation of the support oxide. These compounds, however, were not able to slow down the decrease in dispersion of the Pt nanoparticles. Vanillin and guaiacol stabilize the aluminum oxide more than phenol, anisole, and benzaldehyde because of the larger number of oxygen functionalities that can interact with the alumina. Interestingly, catalyst samples treated in the presence of lignin showed almost no formation of boehmite, no reduction in support or active metal surface area, and no Pt nanoparticle sintering. Furthermore, in the absence of lignin-derived aromatic oxygenates, ethanol forms a coke-like layer on the catalyst, while oxygenates prevent this by adsorption on the support by coordination via the oxygen functionalities.
Original languageEnglish
Pages (from-to)464-473
JournalACS Catalysis
Volume3
Issue number3
DOIs
Publication statusPublished - 2013
Externally publishedYes

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Lignin
Reforming reactions
Aluminum Oxide
Catalysts
Liquids
Nanoparticles
Ethanol
Alumina
Sintering
Metals
Oxygen
Guaiacol
Depolymerization
Physisorption
Oxides
Chemisorption
Phenol
Coke
Phenols
Mass spectrometry

Cite this

Jongerius, A. L., Copeland, J. R., Foo, G. S., Hofmann, J. P., Bruijnincx, P. C. A., Sievers, C., & Weckhuysen, B. M. (2013). Stability of Pt/γ-Al2O3 catalysts in lignin and lignin model compound solutions under liquid phase reforming reaction conditions. ACS Catalysis, 3(3), 464-473. https://doi.org/10.1021/cs300684y
Jongerius, A.L. ; Copeland, J.R. ; Foo, G.S. ; Hofmann, J.P. ; Bruijnincx, P.C.A. ; Sievers, C. ; Weckhuysen, B.M. / Stability of Pt/γ-Al2O3 catalysts in lignin and lignin model compound solutions under liquid phase reforming reaction conditions. In: ACS Catalysis. 2013 ; Vol. 3, No. 3. pp. 464-473.
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Stability of Pt/γ-Al2O3 catalysts in lignin and lignin model compound solutions under liquid phase reforming reaction conditions. / Jongerius, A.L.; Copeland, J.R.; Foo, G.S.; Hofmann, J.P.; Bruijnincx, P.C.A.; Sievers, C.; Weckhuysen, B.M.

In: ACS Catalysis, Vol. 3, No. 3, 2013, p. 464-473.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - Stability of Pt/γ-Al2O3 catalysts in lignin and lignin model compound solutions under liquid phase reforming reaction conditions

AU - Jongerius, A.L.

AU - Copeland, J.R.

AU - Foo, G.S.

AU - Hofmann, J.P.

AU - Bruijnincx, P.C.A.

AU - Sievers, C.

AU - Weckhuysen, B.M.

PY - 2013

Y1 - 2013

N2 - The stability of a 1 wt % Pt/¿-Al2O3 catalyst was tested in an ethanol/water mixture at 225 °C and autogenic pressure, conditions at which it is possible to dissolve and depolymerize various kinds of lignin, and structural changes to the catalysts were studied by means of X-ray diffraction (XRD), 27Al MAS NMR, N2 physisorption, transmission electron microscopy (TEM), H2 chemisorption, elemental analysis, thermogravimetric analysis-mass spectrometry (TGA-MS), and IR. In the absence of reactants the alumina support is found to transform into boehmite within 4 h, leading to a reduction in support surface area, sintering of the supported Pt nanoparticles, and a reduction of active metal surface area. Addition of aromatic oxygenates to mimic the compounds typically obtained by lignin depolymerization leads to a slower transformation of the support oxide. These compounds, however, were not able to slow down the decrease in dispersion of the Pt nanoparticles. Vanillin and guaiacol stabilize the aluminum oxide more than phenol, anisole, and benzaldehyde because of the larger number of oxygen functionalities that can interact with the alumina. Interestingly, catalyst samples treated in the presence of lignin showed almost no formation of boehmite, no reduction in support or active metal surface area, and no Pt nanoparticle sintering. Furthermore, in the absence of lignin-derived aromatic oxygenates, ethanol forms a coke-like layer on the catalyst, while oxygenates prevent this by adsorption on the support by coordination via the oxygen functionalities.

AB - The stability of a 1 wt % Pt/¿-Al2O3 catalyst was tested in an ethanol/water mixture at 225 °C and autogenic pressure, conditions at which it is possible to dissolve and depolymerize various kinds of lignin, and structural changes to the catalysts were studied by means of X-ray diffraction (XRD), 27Al MAS NMR, N2 physisorption, transmission electron microscopy (TEM), H2 chemisorption, elemental analysis, thermogravimetric analysis-mass spectrometry (TGA-MS), and IR. In the absence of reactants the alumina support is found to transform into boehmite within 4 h, leading to a reduction in support surface area, sintering of the supported Pt nanoparticles, and a reduction of active metal surface area. Addition of aromatic oxygenates to mimic the compounds typically obtained by lignin depolymerization leads to a slower transformation of the support oxide. These compounds, however, were not able to slow down the decrease in dispersion of the Pt nanoparticles. Vanillin and guaiacol stabilize the aluminum oxide more than phenol, anisole, and benzaldehyde because of the larger number of oxygen functionalities that can interact with the alumina. Interestingly, catalyst samples treated in the presence of lignin showed almost no formation of boehmite, no reduction in support or active metal surface area, and no Pt nanoparticle sintering. Furthermore, in the absence of lignin-derived aromatic oxygenates, ethanol forms a coke-like layer on the catalyst, while oxygenates prevent this by adsorption on the support by coordination via the oxygen functionalities.

U2 - 10.1021/cs300684y

DO - 10.1021/cs300684y

M3 - Article

VL - 3

SP - 464

EP - 473

JO - ACS Catalysis

JF - ACS Catalysis

SN - 2155-5435

IS - 3

ER -