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Supported molybdenum oxides as effective catalysts for the catalytic fast pyrolysis of lignocellulosic biomass.
- Source :
- Green Chemistry; 10/21/2016, Vol. 18 Issue 20, p5548-5557, 10p
- Publication Year :
- 2016
-
Abstract
- The catalytic fast pyrolysis (CFP) of pine was investigated over 10 wt% MoO<subscript>3</subscript>/TiO<subscript>2</subscript> and MoO<subscript>3</subscript>/ZrO<subscript>2</subscript> at 500 °C and H<subscript>2</subscript> pressures ≤0.75 bar. The product distributions were monitored in real time using a molecular beam mass spectrometer (MBMS). Both supported MoO<subscript>3</subscript> catalysts show different levels of deoxygenation based on the cumulative biomass to MoO<subscript>3</subscript> mass ratio exposed to the catalytic bed. For biomass to MoO<subscript>3</subscript> mass ratios <1.5, predominantly olefinic and aromatic hydrocarbons are produced with no detectable oxygen-containing species. For ratios ≥1.5, partially deoxygenated species comprised of furans and phenols are observed, with a concomitant decrease of olefinic and aromatic hydrocarbons. For ratios ≥5, primary pyrolysis vapours break through the bed, indicating the onset of catalyst deactivation. Product quantification with a tandem micropyrolyzer–GCMS setup shows that fresh supported MoO<subscript>3</subscript> catalysts convert ca. 27 mol% of the original carbon into hydrocarbons comprised predominantly of aromatics (7 C%), olefins (18 C%) and paraffins (2 C%), comparable to the total hydrocarbon yield obtained with HZSM-5 operated under similar reaction conditions. Post-reaction XPS analysis on supported MoO<subscript>3</subscript>/ZrO<subscript>2</subscript> and MoO<subscript>3</subscript>/TiO<subscript>2</subscript> catalysts reveal that ca. 50% of Mo surface species exist in their partially reduced forms (i.e., Mo<superscript>5+</superscript> and Mo<superscript>3+</superscript>), and that catalyst deactivation is likely associated to coking. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14639262
- Volume :
- 18
- Issue :
- 20
- Database :
- Complementary Index
- Journal :
- Green Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 118713379
- Full Text :
- https://doi.org/10.1039/c6gc01189f