The catalysts of three-dimensionally ordered macroporous Ce1−xZrxO2-supported gold nanoparticles for soot combustion: The metal–support interaction

Three-dimensionally ordered macroporous (3DOM) Ce1−xZrxO2-supported gold nanoparticle catalysts were successfully synthesized by the gas bubbling-assisted membrane reduction (GBMR) method. Au nanoparticles with similar sizes are well dispersed and supported on the inner walls of uniform macropores. The active oxygen species (O2-, O−) over 3DOM Au/Ce1−xZrxO2 catalysts are derived from the two approaches: one is direct activation of oxygen on the surface of gold nanoparticles and the other is derived from strong metal–support interaction in which Ce-based supports serve as a reservoir for oxygen in the oxidation reaction. 3DOM Au/Ce1−xZrxO2 catalysts exhibited good catalytic performance for soot combustion, which is strongly related to the role of supports including the structures, the Ce/Zr ratios and the active oxygen supply pathways. The reaction pathways of soot combustion can be classified by two regions. At the low temperature, the soot particles are direct oxidized by active oxygen species migrated from the surface of supported Au catalysts. At the relatively high temperature, the catalytic activity for soot combustion is strongly related to intermediate reactant of NO2 derived from NO oxidation.

The catalytic activities of 3DOM Au/Ce1−xZrxO2 materials for soot oxidation are strongly related to the metal (Au)-supports (Ce) interaction. At low temperature, the soot particles are direct oxidized by active oxygen species migrated from the surface of supported Au catalysts. At high temperatures, the combined effects of active oxygen species and NO2 enhance the rate of soot combustion.Figure optionsDownload high-quality image (162 K)Download as PowerPoint slideHighlights
► 3DOM Au/Ce1−xZrxO2 catalysts with the similar size of Au particle were synthesized by GBMR method.
► The catalysts exhibited high catalytic activities (T10 and SCO2) for soot combustion.
► The catalytic activity depended on the amount of active oxygen species.
► The soot combustion process over 3DOM catalyst was observed by “in situ” TEM images.
► The interaction between the Au nanoparticle and supports were systematically investigated.