Structural and catalytic differences in the effect of Co and Mo as promoters for Pt-based aqueous phase reforming catalysts

Author

• Paul J. Dietrich, Purdue UniversityFollow
• Fred G. Sollberger, Purdue UniversityFollow
• M. Cem Akatay, Purdue University, Birck Nanotechnology CenterFollow
• Eric A. Stach, Purdue University, Birck Nanotechnology CenterFollow
• W.Nicholas Delgass, Purdue UniversityFollow
• Jeffrey T. Miller, Purdue University, Argonne National LabFollow
• Fabio H. Ribeiro, Purdue University, Birck Nanotechnology CenterFollow

Abstract

Reaction rates (site time yields, normalized to CO chemisorption sites) and product selectivity were determined for PtCo, PtMo, and Pt supported on multi-walled carbon nanotubes for aqueous phase reforming of glycerol. The bimetallic PtCo and PtMo catalysts had 4.6x and 5.4x higher glycerol consumption rates than Pt, and 3.9x and 0.6x rates in H-2 formation compared to Pt. Hydrogen generation selectivity was similar on Pt and PtCo, but PtMo had an increase in selectivity to C-O cleavage products, which reduced H-2 yield at conversions over 60% (85-90% hydrogen yield for Pt and PtCo, 65% for PtMo). X-ray absorption spectroscopy and scanning transmission electron microscopy results indicate that PtCo adopts multiple mono- and bimetallic structures (Pt shell/Co core, well-mixed alloy, Pt only), which maintain surface Pt sites that are selective to hydrogen generation while adding a promotional metal that increases reaction rates. This is in contrast to a previously characterized PtMo catalyst which introduced surface sites capable of deoxygenation reactions (in the form of Pt Mo metallic or Pt MoO/OH acid pairs) which result in the observed decrease in selectivity. (C) 2014 Elsevier B.V. All rights reserved.

Keywords

Aqueous phase reforming, Pt bimetallic catalyst, Operand X-ray absorption spectroscopy, Hydrogen production from biomass, SUPPORTED PLATINUM CATALYSTS, DENSITY-FUNCTIONAL THEORY, GAS SHIFT REACTION, ETHYLENE-GLYCOL, OXYGENATED HYDROCARBONS, ELECTRONIC-STRUCTURE, BIMETALLIC SURFACES, RHENIUM CATALYSTS, CARBON NANOTUBES, METAL-CATALYSTS

DOI

10.1016/j.apcatb.2014.03.016

Date of this Version

9-2014

Recommended Citation

Dietrich, Paul J.; Sollberger, Fred G.; Akatay, M. Cem; Stach, Eric A.; Delgass, W.Nicholas; Miller, Jeffrey T.; and Ribeiro, Fabio H., "Structural and catalytic differences in the effect of Co and Mo as promoters for Pt-based aqueous phase reforming catalysts" (2014). Birck and NCN Publications. Paper 1596.
http://dx.doi.org/10.1016/j.apcatb.2014.03.016