Catalytic Oxidation of Propylene, Toluene, Carbon Monoxide, and Carbon Black over Au/CeO₂ Solids: Comparing the Impregnation and the Deposition‐Precipitation Methods

Abstract

Au/CeO2 solids were prepared by two methods: deposition-precipitation (DP) and impregnation (Imp). The prepared solids were calcined under air at 400°C. Both types of catalysts have been tested in the total oxidation of propylene, toluene, carbon monoxide, and carbon black. Au/CeO2-DP solids were the most reactive owing to the high number of gold nanoparticles and Au+ species and the low concentration of Cl− ions present on its surface compared to those observed in Au/CeO2-Imp solids.

Relationship between hydrothermal temperatures and structural properties of CeO2 and enhanced catalytic activity of propene/toluene/CO oxidation by Au/CeO2 catalysts

“…Based on T 50 for propene oxidation of the Au/CeO 2 X catalyst series, temperatures were lower (in the 70-95 °C range) than those of the parent CeO 2 catalysts. The light-off temperature was measured at 150 °C, coincident with the value reported in the literature for 4 wt% Au/CeO 2 prepared by the DP technique (Aboukaïs et al, 2013). The T 50 value in the present study was higher than Pt and Pd catalysts.…”

“…In a study similar to the present one, the catalytic oxidation efficiency of 4-wt% Au/CeO 2 -DP was tested against a gas mixture comprising propene (6,000 ppm), toluene (2000 ppm), and CO (1,000 ppm); results indicated excellent catalytic activity for propene and CO oxidation, due to the presence of highly dispersed Au nanoparticles only 3.9 nm in size ( Aboukaïs et al, 2013 ). The T 50 of propene conversion was approximately 170°C, and the T 90 of CO oxidation was around 25°C.…”

“…Nevertheless, Au/ CeO 2 180 exhibited a higher T 90 of CO conversion than Au/ CeO 2 120, and the difference was 10 °C. This observation indicated that the catalytic activity at high reaction temperature did not rely on only the nature of Au, but also In a study similar to the present one, the catalytic oxidation efficiency of 4-wt% Au/CeO 2 -DP was tested against a gas mixture comprising propene (6,000 ppm), toluene (2000 ppm), and CO (1,000 ppm); results indicated excellent catalytic activity for propene and CO oxidation, due to the presence of highly dispersed Au nanoparticles only 3.9 nm in size (Aboukaïs et al, 2013). The T 50 of propene conversion was approximately 170 °C, and the T 90 of CO oxidation was around 25 °C.…”

“…Even though VOC removal via oxidation reactions over Au catalysts has been studied for over a decade ( Scirè et al, 2003 ; Solsona et al, 2006 ; Shen et al, 2008 ), the relevant experiments were conducted independently on each reactant, which might not be a practical approach for application to real-life scenarios. The oxidation of propene/toluene/CO mixtures over Au/CeO 2 catalysts has been previously studied, and the experiments conducted only focused on the effect that Au catalyst preparation had on the catalytic performance ( Aboukaïs et al, 2013 ). The high catalytic performance of Au/CeO 2 depends on the increased oxygen mobility in the reducible oxide support resulting from Au introduction.…”

Gold and Ceria as Catalysts for VOC Abatement: A Review

“…The importance of the interface between gold and ceria was underlined in the operando IR study of methanol oxidation [139]. The comparison of deposition-precipitation and impregnation method was studied by Aboukaïs et al [140] for catalytic oxidation of propylene and toluene. They confirmed that the catalysts prepared by deposition-precipitation were more active than those prepared by impregnation due to the high number of gold nanoparticles and Au + species and the low concentration of Cl − ions present on its surface.…”