Revealing the unexpected promotion effect of EuOx on Pt/CeO2 catalysts for catalytic combustion of toluene

Abstract Pt/Eu 2 O 3 -CeO 2 materials with different Eu concentrations were prepared and applied to toluene destruction, and the remarkable promotion impact of EuO x on Pt/CeO 2 can be observed. The characterization results reveal that the presence of EuO x significantly enhances the redox property, lattice O concentration, and Ce 3+ ratio of the Pt/CeO 2 material, which facilitates the dispersion and activity of Pt active sites and thus accelerates the decomposition process of toluene. Among all catalysts, a sample with an Eu content of 2.5 at.% (Pt/EC-2.5) possesses the best catalytic activity with 0.09 vol% of toluene completely destructed at 200 °C under a relatively high GHSV of 50000 h −1 . The possible reaction pathway and mechanism of toluene combustion over Pt/Eu 2 O 3 -CeO 2 samples are presented according to in-situ DRIFTS, which confirms that the toluene oxidation process obeys the Mars-van Krevelen mechanism with aldehydes and ketones as primary organic intermediates.