Three-Dimensionally
Ordered Macroporous Mn<sub><i>x</i></sub>Ce<sub>1–<i>x</i></sub>O<sub>δ</sub> and Pt/Mn<sub>0.5</sub>Ce<sub>0.5</sub>O<sub>δ</sub> Catalysts: Synthesis
and Catalytic Performance for Soot Oxidation
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Abstract
Three-dimensionally ordered macroporous
(3DOM) Mn<sub><i>x</i></sub>Ce<sub>1–<i>x</i></sub>O<sub>δ</sub> oxides with different ratios of Mn to Ce
were successfully synthesized
by colloidal crystal template (CCT) method, and 3DOM Pt/Mn<sub>0.5</sub>Ce<sub>0.5</sub>O<sub>δ</sub> with varied Pt loadings were
prepared by in situ ethylene glycol (EG) reduction method. 3DOM Mn<sub><i>x</i></sub>Ce<sub>1–<i>x</i></sub>O<sub>δ</sub> supports exhibited well-defined 3DOM nanostructure,
and Pt nanoparticles (NPs) with 1–2 nm size were evenly dispersed
on the inner walls of uniform macropores. Among 3DOM Mn<sub><i>x</i></sub>Ce<sub>1–<i>x</i></sub>O<sub>δ</sub> catalysts, 3DOM Mn<sub>0.5</sub>Ce<sub>0.5</sub>O<sub>δ</sub> showed excellent catalytic activity for soot combustion; i.e., <i>T</i><sub>50</sub> is 358 °C and <i>S</i><sub>CO<sub>2</sub></sub><sup>m</sup> is
94.2%. 3DOM Pt/Mn<sub>0.5</sub>Ce<sub>0.5</sub>O<sub>δ</sub> catalysts exhibited higher activity than 3DOM Mn<sub><i>x</i></sub>Ce<sub>1–<i>x</i></sub>O<sub>δ</sub> and 3 wt % Pt/Mn<sub>0.5</sub>Ce<sub>0.5</sub>O<sub>δ</sub> showed the highest catalytic activity for soot combustion (<i>T</i><sub>50</sub> is 342 °C and <i>S</i><sub>CO<sub>2</sub></sub><sup>m</sup> is
96.7%). Macropores effect, synergistic effects between Mn and Ce,
and synergistic effects between Pt and Mn<sub>0.5</sub>Ce<sub>0.5</sub>O<sub>δ</sub> support are contributed to high catalytic activities
of as-prepared catalysts
