Architecture of Pt-Co Bimetallic Catalysts for Catalytic CO Oxidation

Pt?Co nanocatalysts have been synthesized and tested for both preferential oxidation of CO in excess H2 (PROX) and CO oxidation in the absence of H2 (COOX). Structural characterization and reaction results suggest that a Pt?Co catalyst architecture consisting of Pt nanoparticles decorated with highly dispersed CoO nanostructures is the active structure for both reactions. The highly active CoO-on-Pt catalysts can be prepared by reduction of as-prepared Pt?Co catalysts at an intermediate temperature or by reactivation of an acid-leached Pt?Co catalyst at a similar temperature. A comparative study of Pt?Fe, Pt?Co, and Pt?Ni catalysts reveals that interface confinement effects are dominant in all TMOx-on-Pt systems (TM=Fe, Co, and Ni). However, the activity and stability in both PROX and COOX reactions for each of these catalyst systems is variable