Bi2O3/Co3O4 catalysts prepared by the impregnation method were investigated for the selective catalytic reduction of NO by C3H6 (C3H6-SCR) in the presence of O2. Their physicochemical properties were analyzed with SEM, XRD, H2-TPR, XPS, PL and IR measurements. It was found that the deposition of Bi2O3 on Co3O4 nanoplates enhanced the catalytic activity, especially at low reaction temperature. The SO2 tolerance of Co3O4 in C3H6-SCR activity was also improved with the addition of Bi2O3. Among all catalysts tested, 10.0 wt% Bi2O3/Co3O4 achieved a 90% NO conversion at 200 °C with the total flow rate of 200 mL min-1 (GHSV 30 000 h-1). No loss in its C3H6-SCR activity was observed at different temperatures after the addition of 100 ppm of SO2 to the reaction mixture. These enhanced catalytic behaviors may be associated with the improved oxidizing characteristics of 10.0 wt% Bi2O3/Co3O2. XRD results showed that Bi2O3 entered the lattice of Co3O4, resulting in the formation of lattice distortion and structural defects. H2-TPR results showed that the reduction of Co3O4 was promoted and the diffusion of oxygen was accelerated with the addition of Bi2O3. XPS measurements implied that more Co3+ formed on the 10.0% Bi2O3/Co3O2 catalysts. The improved oxidizing characteristics of the catalyst with the addition of Bi2O3 due to the synergistic effect of the nanostructure hybrid, thus enhanced the C3H6-SCR reaction and hindered the oxidization of SO2. Therefore, the 10.0% Bi2O3/Co3O4 catalyst exhibited the highest NO conversion and strongest SO2 tolerance ability.
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