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对不同Sb/Fe比,500℃焙烧的样品,采用了X射线衍射、穆斯堡尔谱、比磁化强度、红外光谱、表面微区元素分析及甲苯氧化生成苯甲醛的活性测定等进行了研究。结果表明,在催化剂的表面上均有锑富集,锑的比富集量愈大,苯甲醛的选择性也愈高。不含铁样品的物相为Sb_2O_4,生成苯甲醛的选择性最高。当Sb/Fe=5时,物相中除Sb_2O_4、FeSbo_4外,还有FeSb_2O_6生成。随着Fe含量增加,Sb/Fe比高于5时,样品物相为Sb_2O_4和FeSbO_4。在所采用的制备条件下得到的Fe-Sb样品中,观察到有明显的固溶作用。此外,本文还对Fe-Sb氧化物催化剂上甲苯的反应机理进行了讨论。
The samples calcined at 500 ℃ with different Sb / Fe ratios were studied by X-ray diffraction, Mossbauer spectroscopy, specific magnetization, infrared spectroscopy, surface microelement analysis and the activity of toluene oxidation to benzaldehyde . The results show that there are antimony enrichment on the surface of the catalyst, the greater the specific enrichment of antimony, the higher the selectivity of benzaldehyde. The non-ferrous sample phase is Sb 2 O 4, the highest selectivity to benzaldehyde. When Sb / Fe = 5, in addition to Sb_2O_4 and FeSbo_4, there are FeSb_2O_6 in the phase. With the increase of Fe content, Sb / Fe ratio higher than 5, the sample phase is Sb_2O_4 and FeSbO_4. In the Fe-Sb samples obtained under the used preparation conditions, a significant solid solution was observed. In addition, the reaction mechanism of toluene on Fe-Sb oxide catalyst was also discussed.