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A 0.4 wt%Pt/Ce 0.76 Zr 0.19 Zn 0.05 O 1.95 catalyst was prepared by the evaporative drying method. The catalytic toluene oxidation activity of the catalyst was investigated and the calcination temperature dependence on the toluene oxidation activity was characterized. It was confirmed that only CO 2 and steam were produced by the complete oxidation of toluene, and no toluene-derived compounds were detected as by-products with a gas chromatography-mass spectrometer. Toluene was completely oxidized at 320 °C on the 0.4 wt%Pt/Ce 0.76 Zr 0.19 Zn 0.05 O 1.95 catalyst calcined at 500 °C. The toluene oxidation activity slightly decreased with increasing the calcination temperature of the catalyst. However, significant deactivation was not recognized in the present 0.4 wt%Pt/Ce 0.76 Zr 0.19 Zn 0.05 O 1.95 catalyst, and toluene was completely oxidized at 360 °C even after calcination at 1000 °C. From these results, it became obvious that the 0.4 wt%Pt/Ce 0.76 Zr 0.19 Zn 0.05 O 1.95 catalyst has high thermal stability for toluene oxidation activity.

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1 wt % Pt/11 wt % (Co1−xCux)3O4−δ/16 wt % Ce0.62Zr0.20Sn0.18O2.0/γ-Al2O3 catalysts were prepared to realize complete combustion of toluene at lower temperatures than that of a 1 wt % Pt/11 wt % Co3O4/16 wt % Ce0.62Zr0.20Sn0.18O2.0/γ-Al2O3 catalyst previously reported by our group without increasing the amount of platinum. Addition of copper into the Co3O4 lattice was effective to facilitate oxygen release and storage, and thereby, the toluene oxidation activity was enhanced. The highest activity for the combustion of toluene was observed using a 1 wt % Pt/13 wt % (Co0.97Cu0.03)3O4−δ/16 wt % Ce0.62Zr0.20Sn0.18O2.0/γ-Al2O3 catalyst, and despite a smaller platinum loading in the present catalyst, toluene was completely oxidized to carbon dioxide and water vapor at the lower temperature of 140 °C compared to that (160 °C) using 1 wt % Pt/11 wt % Co3O4/16 wt % Ce0.62Zr0.20Sn0.18O2.0/γ-Al2O3.

A 1wt%Pt/Co 3 O 4 /CeO 2-ZrO 2-SnO 2 /γ-Al 2 O 3 catalyst was prepared to realize complete combustion of toluene at the lowest temperature possible without excessive use of platinum particles. The addition of Co 3 O 4 to Pt/CeO 2-ZrO 2-SnO 2 /γ-Al 2 O 3 as a promoter was effective in decreasing the amount of platinum without significant reduction in the catalytic activity. The highest activity for the combustion of toluene was observed using the 1wt%Pt/11wt%Co 3 O 4 /16wt%Ce 0.62 Zr 0.20 Sn 0.18 O 2.0 /γ-Al 2 O 3 catalyst, and despite a smaller platinum loading in the present catalyst, toluene was completely oxidized to carbon dioxide and water vapor at a lower temperature of 160 o C compared to that using 5wt%Pt/γ-Al 2 O 3 at 170 o C.