Aqueous Phase Glycerol Reforming by PtMo Bimetallic Nano-Particle Catalyst: Product Selectivity and Structural Characterization

Journal Article · Thu Mar 01 04:00:00 EST 2012 · Topics in Catalysis

OSTI ID:1045323

A, Stach E; Dietrich, P J; Lobo-Lapidus, R J; Wu, T; Sumer, A; Akatay, M C; Fingland, B R; Guo, N; Dumesic, J A; Marshall, C L; Jellinek, J; Delgass, W N; Ribeiro, F H; Miller, J T

A carbon supported PtMo aqueous phase reforming catalyst for producing hydrogen from glycerol was characterized by analysis of the reaction products and pathway, TEM, XPS and XAS spectroscopy. Operando X-ray absorption spectroscopy (XAS) indicates the catalyst consists of bimetallic nano-particles with a Pt rich core and a Mo rich surface. XAS of adsorbed CO indicates that approximately 25% of the surface atoms are Pt. X-ray photoelectron spectroscopy indicates that there is unreduced and partially reduced Mo oxide (MoO{sub 3} and MoO{sub 2}), and Pt-rich PtMo bimetallic nano-particles. The average size measured by transmission electron microscopy of the fresh PtMo nano-particles is about 2 nm, which increases in size to 5 nm after 30 days of glycerol reforming at 31 bar and 503 K. The catalyst structure differs from the most energetically stable structure predicted by density functional theory (DFT) calculations for metallic Pt and Mo atoms. However, DFT indicates that for nano-particles composed of metallic Pt and Mo oxide, the Mo oxide is at the particle surface. Subsequent reduction would lead to the experimentally observed structure. The aqueous phase reforming reaction products and intermediates are consistent with both C-C and C-OH bond cleavage to generate H{sub 2}/CO{sub 2} or the side product CH{sub 4}. While the H{sub 2} selectivity at low conversion is about 75%, cleavage of C-OH bonds leads to liquid products with saturated carbon atoms. At high conversions (to gas), these will produced additional CH{sub 4} reducing the H{sub 2} yield and selectivity.

• Research Organization: Brookhaven National Laboratory (BNL) Center for Functional Nanomaterials
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1045323
• Report Number(s): BNL--98237-2012-JA; KC020401H
• Journal Information: Topics in Catalysis, Journal Name: Topics in Catalysis Journal Issue: 1-2 Vol. 55
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
09 BIOMASS FUELS
77 NANOSCIENCE AND NANOTECHNOLOGY
ABSORPTION SPECTROSCOPY
ATOMS
BIOMASS
CARBON
CATALYSTS
CLEAVAGE
FUNCTIONALS
GLYCEROL
HYDROGEN
OXIDES
SPECTROSCOPY
TRANSMISSION ELECTRON MICROSCOPY
X-RAY PHOTOELECTRON SPECTROSCOPY
functional nanomaterials