不同载体成型的Mo/ZSM-5催化剂上甲烷无氧芳构化反应

Methane Dehydroaromatization in the Absence of Oxygen over Mo/ZSM-5 Extruded with Different Oxides

以不同氧化物为载体,通过挤条成型法制备了Mo/ZSM-5催化剂,考察了其催化甲烷无氧芳构化反应性能.采用吸附吡啶红外光谱、氨程序升温脱附和氢程序升温还原等方法对催化剂进行了表征.结果表明,ZnO的添加使催化剂的强酸量减少,强B酸比例降低,Mo物种还原能力提高,因而催化剂表现出较高的甲烷芳构化活性和较低的积炭选择性.

The Mo/ZSM-5 catalysts extruded with various oxides as supports were prepared. Fourier transform infrared spectroscopy of pyridine adsorption, NH3 temperature-programmed desorption, and H2 temperature-programmed reduction were employed to characterize the catalysts. Methane dehydroaromatization in the absence of oxygen over the catalysts was investigated in a fixed-bed reactor. The results showed that the catalyst extruded with ZnO presented the highest activity among all the catalysts tested. Methane conversion and aromatics selectivity were 9.3% and 53.7%, respectively. The improved activity of the catalyst extruded with ZnO for methane dehydroaromatization was attributed to its appropriated Brnsted acidity. Moreover, addition of ZnO, an n-type semiconductor, benefited the reduction of Mo6＋ species.