In this work, the physico-chemical properties of the La_1-xSr_xCo_0.8Fe_0.2O₃ (x = 0, 0.3，0.4，0.5，0.6) catalysts were systematically studied as well as their catalytic activity for NO oxidation. When Sr²⁺ substituted at La³⁺ site, [CoO₆] octahedral distortion is amended and the crystal structure transited from rhombohedral to cubic. Co(III) electronic configuration turned from high/intermediate spin state to low spin sate with empty e_g filling. Imbalanced positive charge induced by Sr²⁺ was compensated by tetravalent Co(IV) ions and oxygen deficiencies together. All these factors resulted in better reducibility of Co, increasing oxygen deficiencies and more mobile oxygen species. Thus, NO conversion of 67–69% was attained over the Sr-doped catalysts at 300 °C, much higher than the undoped catalysts (NO conversion of 24.3%). A significant decrease of the apparent activation energy (E_a), from 68 kJ/mol down to ~52 kJ/mol, was observed as well. Based on the kinetics results, NO oxidation over the perovskite catalysts is a typical superficial process determined by adsorbed NO and surface oxygen species.

本文系统地研究了La _1-x Sr _x Co _0.8 Fe _0.2 O ₃（x = 0，0.3，0.4，0.5,0.6）催化剂的物理化学性质及其对NO氧化的催化活性。当Sr ²⁺在La ³⁺位点被取代时，[CoO ₆ ]八面体形变被修正，晶体结构从菱形向立方转变。Co（III）电子结构从高/中旋态转变为低旋态，并充满了空的e _g。Sr ²⁺引起的正电荷失衡被四价Co（IV）离子和氧缺乏共同补偿。所有这些因素导致更好的Co还原性，增加了氧气缺乏症和更多的流动性氧。因此，在300°C下，掺Sr的催化剂的NO转化率为67-69％，远高于未掺杂的催化剂（NO的转化率为24.3％）。还观察到表观活化能（E _a）从68 kJ / mol显着降低至〜52 kJ / mol。基于动力学结果，钙钛矿催化剂上的NO氧化是由吸附的NO和表面氧种类决定的典型表面过程。