Enhanced Soot Oxidation Performance of CeO2-Promoted La2O2SO4 Catalytic Oxygen Storage Materials for Gasoline Particulate Filters

This study investigates the synergistic promotional effects of CeO2 and La2O2SO4 as composite catalytic oxygen storage systems for soot oxidation in Gasoline Particulate Filters (GPFs) across a broad operating temperature range. Two 5 wt % CeO2-promoted Lanthanum oxysulfate compounds were prepared by mechanical mixing of pure phases or by supporting CeO2 via incipient wetness impregnation with a cerium nitrate precursor. The soot oxidation activity was evaluated using Thermogravimetric Analysis coupled with Mass Spectrometry (TG-MS) under both anaerobic and lean-O2 (1% vol.) environments, with the performance benchmarked against pure La- or Pr-oxysulfates and CeO2 reference materials. Comprehensive characterization via XRD, SEM, N2-physisorption, and H2-TPR revealed that the observed synergistic effects transcend the simple additive properties of the individual components.