Investigation of the Dual‐Regulatory Mechanism of Zr in MnRE1‐xZrxO2+δ Oxide Catalysts for NO Oxidation

Utilizing Diesel Oxidation Catalysts (DOC) to partially oxidize NO to NO₂ is a crucial step in controlling NO_x emissions from diesel engines. However, enhancing both catalytic activity and hydrothermal stability remains a significant challenge. Benefiting from abundant asymmetric oxygen vacancies and increased Mn⁴⁺ content, MnRE_0.5Zr_0.5 exhibits superior NO oxidation performance (T₆₃ = 337 °C) and hydrothermal aging resistance (T₅₂ = 340 °C) compared to the undoped sample (T₅₃ = 365 °C). XPS, Raman, TPR, and XAS are employed to verify the elevation of oxygen vacancy concentration and Mn valence state modulation due to Zr introduction. Furthermore, compared to MnRE (1.36 eV), the formation energy of oxygen vacancies in MnRE_0.5Zr_0.5 is significantly reduced (0.17 eV). This work elucidates the dual regulatory role of Zr in the Mn-RE-Zr ternary system, providing theoretical support and guidance for the design of catalysts for atmospheric pollutant purification and industrial catalysis.