Effect of Co Loading on the Activity and Selectivity of PtCo Aqueous Phase Reforming Catalysts

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

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The reaction site time yields (STYs, normalized to CO chemisorption sites) and product selectivity were measured for a series of bimetallic, multiwalled carbon nanotube supported PtCo catalysts with varying Pt/Co ratios for aqueous phase glycerol reforming. The STYs for all products increased by factors of around 2 for PtCo 1:0.5 and 1:1, and a factor of 4 for PtCo 1:5 relative to a monometallic Pt catalyst. The PtCo catalysts had similar hydrogen selectivity (>85%) at glycerol conversions up to 60%. X-ray absorption spectroscopy and scanning transmission electron microscopy characterization revealed that PtCo catalysts adopt monometallic Pt, mixed PtCo alloy, and Pt shell/Co core particle configurations. A linear correlation between the fraction of mixed PtCo alloy particles and the STY was found, indicating that higher Co loading resulted in a higher fraction of mixed PtCo alloy particles (the promoted phase) that provided the STY increase.


Nanoscience and Nanotechnology