摘要
通过原位X射线衍射、X光电子能谱、程序升温脱附等测试方法,研究了甲苯在铜锰氧化物(Cu-Mn-O)上催化氧化的机理。提出反应过程中形成的还原态Cu(Ⅰ,0)是吸附甲苯的主要活性中心,锰的氧化物起着传递晶格氧参与甲苯氧化的作用,两种活性组元必须协同作用才能呈现优良的氧化活性。
Catalytic oxidation of toluene on Cu-Mn mixed uxide catalysis was studied by in-situ XRD, XPD, TPD and activity test, XRD and XPS studies of the fresh Cu-Mn-O Catalysts showed that the copper component was present as CuO, and Mn was in X-ray 'amorphous' MrC2 form. An oxidation reaction-m-sifu XRD cell of our own design was used to monitor the states of catalysis during reaction. It was revealed that there were valence charges both of Cu and Mn in thereaction. CuO was partially convented to Cu(I,0). which became the main adsorption sites for toluene according to the TPD results. XPS analysis indicated that Mn-O and Cu-Mn-O had smaller Ols binding energies in comparison with Cu-O, the fact suggested that MnO3 was an important catalytic component transferring its active surface oxygen to catalyze the oxidation of adsorbed toluene. Meanwhile, Cu( I ,0) could be easily reoxidized. Thus, the catalytic oxidation of toluene on Cu-Mn mixed oxides was believed to proceed via the reduction and oxidation cycles of the catalysts.Based on the experimental results, a mechanism of catalytic oxidation of toluene was proposed and discussed.
