Reduced SrTiO3-Supported Pt-Cu Alloy Nanoparticles for Preferential Oxidation of CO in Excess Hydrogen
Activity and long-term stability of oxide-metal heterostructure catalyst can be engineered through tuning oxygen storage capacity (OSC) of support and careful control of composition of the supported metal nanoparticle. In this work, we probe these two factors for microwave-synthesized PtCu alloy nanoparticles supported on reduced-SrTiO3. The heterostructures are tested for their activity towards preferential CO oxidation in presence of H2 at the typical operating temperatures used for polymer electrolyte membrane fuel cell (PEMFC). Through controlled temperature programmed reduction/oxidation (TPR/TPO) experiments, we show that the OSC of the support can be enhanced through heavy surface reduction of the SrTiO3. Adsorption-desorption experiments establish the strikingly different CO adsorption behavior over monometallic Pt and PtCu alloy nanoparticles. Through detailed catalytic studies, we establish a trend of selectivity and stability of CO conversions over the PtCu alloy catalysts, that can indeed be tuned by varying the PtCu composition in a facile microwave synthesis.