Highly Reactive Peroxide Species Promoted Soot Oxidation over an Ordered Macroporous Ce0.8Zr0.2O2 Integrated Catalyzed Diesel Particulate Filter

Particulate matter, represented by soot particles, poses a significant global environmental threat, necessitating efficient control technology. Here, we innovatively designed and elaborately fabricated ordered hierarchical macroporous catalysts of Ce_0.8Zr_0.2O₂ (OM CZO) integrated on a catalyzed diesel particulate filter (CDPF) using the self-assembly method. An oxygen-vacancy-enriched ordered macroporous Ce_0.8Zr_0.2O₂ catalyst (V_O-OM CZO) integrated CDPF was synthesized by subsequent NaBH₄ reduction. The V_O-OM CZO integrated CDPF exhibited a markedly enhanced soot oxidation activity compared to OM CZO and powder CZO coated CDPFs (T₅₀: 430 vs 490 and 545 °C, respectively). The well-defined OM structure of the V_O-OM CZO catalysts effectively improves the contact efficiency between soot and the catalysts. Meanwhile, oxygen vacancies trigger the formation of a large amount of highly reactive peroxide species (O₂^2-) from molecular oxygen (O₂) through electron abstraction from the three adjacent Ce³⁺ (3Ce³⁺ + Vö + O₂ → 3Ce⁴⁺ + O₂^2-), contributing to the efficient soot oxidation. This work demonstrates the fabrication of the ordered macroporous CZO integrated CDPF and reveals the importance of structure and surface engineering in soot oxidation, which sheds light on the design of highly efficient PM capture and removal devices.