In-situ modified the surface of Pt-doped perovskite catalyst for soot oxidation

In-situ modification is studied in this work on LaCo_1-xPt_xO₃ for soot oxidation. A series of perovskite catalysts LaCo_1-xPt_xO₃ (by sol-gel method) are modified with 30% H₂O₂. XRD, TEM, SEM, BET, XPS, Raman, in-situ DRIFTS, H₂-TPR and TGA are used to investigate physicochemical properties of catalysts. TGA results show that all doped catalysts have a lower temperature of soot conversion, especially LaCo_0.94Pt_0.06O₃ (T₅₀ = 437 °C). The T₅₀ of the catalyst with modification by H₂O₂ solution decreases at least 20 °C compared with the doped catalysts. A highly symmetrical structure and an obvious amorphous layer about 3-5 nm are observed in the modified catalysts. According to the XPS study, the symmetrical structure benefits to the movement of oxygen vacancy thus catalyst captures more adsorbed oxygen (about 95%). And the amorphous surface could adsorb more oxygen species. In addition, all catalysts show excellent aging resistance performance. The reaction mechanism of catalyst for soot oxidation is presented in the end.