Support structure and reduction treatment effects on CO oxidation of SiO2 nanospheres and CeO2 nanorods supported ruthenium catalysts

Junhao Li; Zhongqi Liu; Ruigang Wang

doi:10.1016/j.jcis.2018.07.046

Support structure and reduction treatment effects on CO oxidation of SiO₂ nanospheres and CeO₂ nanorods supported ruthenium catalysts

J Colloid Interface Sci. 2018 Dec 1:531:204-215. doi: 10.1016/j.jcis.2018.07.046. Epub 2018 Jul 19.

Authors

Junhao Li¹, Zhongqi Liu¹, Ruigang Wang²

Affiliations

¹ Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL 35487, United States.
² Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL 35487, United States. Electronic address: rwang@eng.ua.edu.

PMID: 30032007
DOI: 10.1016/j.jcis.2018.07.046

Abstract

The effects of support structure and reducibility, oxidation and reduction treatment and ruthenium loading amount were studied in SiO₂ nanospheres and CeO₂ nanorods supported ruthenium catalysts on CO oxidation. 0.4, 1.0 and 5.0 wt% Ru were impregnated on SiO₂ nanospheres and CeO₂ 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, H₂-TPR, and CO oxidation analyses were carried out to understand the effects of RuO_x-support interaction, oxidation and reduction treatment and ruthenium loading amount on the catalytic performance. Compared to SiO₂ nanospheres supported ruthenium catalysts, both the oxidized and reduced RuO_x/CeO₂ catalysts exhibited superior catalytic performance in terms of CO conversion and low-temperature hydrogen consumption. After the reduction treatment in H₂, the RuO_x/CeO₂ catalysts is further activated for low-temperature CO conversion. Especially, the 5.0 wt% Ru/CeO₂-reduction sample can achieve ∼9% CO conversion at near room temperature. The enhanced low-temperature activity of CeO₂ nanorods supported ruthenium catalysts was correlated strongly to the surface defects on CeO₂ nanorods, dispersion of RuO_x, and interfacial structures between CeO₂ and RuO_x.

Keywords: CO oxidation; Reduction treatment; Ru catalyst; Support effect.