Insight into soot oxidation performance and kinetics of novel Ce/La modified Cs-V based non-noble metal catalysts

The catalytic diesel particulate filter (CDPF) is the most widely used after-treatment device for controlling diesel engine soot emissions. The development of cost-effective catalysts is crucial for diesel engines to comply with future ultra-low emission regulations. This paper studies a new type of Ce/La modified Cs-V non-noble metal CDPF catalyst. Three test catalysts (Cs-V, Cs-V-5 %Ce, and Cs-V-5 %La) were formulated to explore the physical properties, activity, and sulfur resistance through XRD, SEM, XPS, and TPO tests. And TGA tests with different catalyst-to-soot mass ratios were designed to analyze the reaction kinetics. The results show that the soot oxidation process is divided into three stages: slow oxidation, rapid oxidation, and soot burnout. SEM and XRD results show that, compared with Ce doping, La-doped catalysts have less damage to the microstructure of the first active component, Cs₂V₄O₁₁. XPS results show that the introduction of Ce and La is beneficial to the formation of oxygen vacancies and lattice distortion, increasing the proportion of active oxygen species, thereby improving the soot oxidation activity, among which La-doped active oxygen species have the highest proportion (94 %). And the Cs-V-5 %La catalyst has the best effect on improving the soot conversion of the three stages. The fresh state has the best low-temperature activity index, the lowest characteristic temperature (T₅₀ of 374 °C) and activation energy (115.01 kJ/mol), and excellent sulfur resistance. The soot conversion and oxidation speed of the three stages decreases, duration lengthens, and activation energy increases by more than 100 kJ/mol as catalyst-to-soot mass ratios decrease.