Support structure and reduction treatment effects on CO oxidation of SiO nanospheres and CeO nanorods supported ruthenium catalysts.

The effects of support structure and reducibility, oxidation and reduction treatment and ruthenium loading amount were studied in SiO nanospheres and CeO nanorods supported ruthenium catalysts on CO oxidation. 0.4, 1.0 and 5.0 wt% Ru were impregnated on SiO nanospheres and CeO nanorods using precipitation method and then the samples were oxidized in air. Half of the oxidized samples were also further reduced under hydrogen atmosphere to compare the effect of reduction treatment on the catalytic activity. Detailed XRD, Raman, TEM, H-TPR, and CO oxidation analyses were carried out to understand the effects of RuO-support interaction, oxidation and reduction treatment and ruthenium loading amount on the catalytic performance. Compared to SiO nanospheres supported ruthenium catalysts, both the oxidized and reduced RuO/CeO catalysts exhibited superior catalytic performance in terms of CO conversion and low-temperature hydrogen consumption. After the reduction treatment in H, the RuO/CeO catalysts is further activated for low-temperature CO conversion. Especially, the 5.0 wt% Ru/CeO-reduction sample can achieve ∼9% CO conversion at near room temperature. The enhanced low-temperature activity of CeO nanorods supported ruthenium catalysts was correlated strongly to the surface defects on CeO nanorods, dispersion of RuO, and interfacial structures between CeO and RuO.