Electronic Metal-Support Interactions in Pt/FeOx Nanospheres for CO Oxidation

2019 
Abstract Catalysts containing heterostructures consisting of composite metal/metal oxides have been proven to be very active for many catalytic reactions. In this work, Pt/FeO x heterostructures, including Pt/Fe 2 O 3 and Pt/Fe 3 O 4 nanospheres, were synthesized and used for catalytic oxidation of CO. Fe 2 O 3 and Fe 3 O 4 nanospheres were synthesized by hydrothermal methods, and then platinum precursors were in situ reduced on the prepared FeO x in ethylene glycol solutions. The results of the activity test showed that the Pt/Fe 3 O 4 nanospheres exhibited much higher catalytic activity of CO oxidation than the Pt/Fe 2 O 3 nanospheres over the entire temperature range of 50 °C to 225 °C. Complete CO oxidation could be achieved on the Pt/Fe 3 O 4 catalysts at temperatures above 150 °C, while the full CO conversion required a temperature of 225 °C on the Pt/Fe 2 O 3 catalysts. Several characterization techniques were used to investigate the physicochemical properties in light of the activity differences of the prepared catalysts. The combined results of TEM and XRD showed that Pt/Fe 3 O 4 and Pt/Fe 2 O 3 were comprised of Pt nanoparticles with an average crystallite size of 3.7 nm and 3.6 nm, respectively. The Pt nanoparticles could uniformly distribute throughout the FeO x nanosphere supports. According to XPS and H 2 -TPR characterizations, surface chemisorbed oxygen was readily formed on the Pt/Fe 3 O 4 nanospheres, and a synergistic interaction might exist between Pt and Fe 3 O 4 nanospheres. The presence of Pt nanoparticles facilitated the activation of surface chemisorbed oxygen, thus mainly contributed to the CO oxidation. In situ DRIFTS results indicated that the oxygen activation was a rate-limiting step in the catalytic oxidation process. Linearly adsorbed CO species on the Pt sites were then oxidized into CO 2 .
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    27
    References
    11
    Citations
    NaN
    KQI
    []