MOx/Y催化剂常温催化臭氧氧化甲苯的性能

The catalytic performance of MOx/Y catalyst in toluene oxidation with ozone at room temperature

摘要:

采用等体积浸渍法制备MOx/Y催化剂，用于常温催化臭氧氧化甲苯反应。采用X射线衍射（XRD）、N2吸附-脱附、氢气程序升温还原（H2-TPR）、甲苯吸附等方法对催化剂结构进行表征。结果表明：10%MnO2/Y催化剂具有较大的比表面积和孔容积，较好的甲苯吸附性能，促进甲苯与臭氧充分反应，有利于甲苯转化率和COx选择性的提高；第二组分CuO的加入，CuO与MnO2之间存在相互作用，提高了氧化还原性能，促进产物中CO进一步氧化转化为CO2，进而提高COx中CO2与CO摩尔比。在常温催化臭氧氧化甲苯反应中，5%MnO2-5%CuO/Y催化剂表现出较优的催化活性，t95为240 min，COx选择性为80.6%，CO2与CO摩尔比为4.970。GC-MS结果表明，反应副产物苯甲酸和甲酸苯甲酯堵塞催化剂孔道，占据催化剂表面活性位，导致催化剂失活。

Abstract:

10%MOx/Y (M= Mn, Co, Ni, Fe, Ce, Cu) and 5%MnO2-5%MOx/Y (M= Ce, Co, Cu) catalysts prepared by incipient-wetness impregnation method for toluene oxidation with ozone at room temperature. The catalysts were characterized by XRD, BET, H2-TPR and toluene adsorption techniques. The re-sults revealed that 10%MnO2/Y catalyst showed a larger surface area and pore volume, a better tolu-ene adsorption performance, promoting the reaction of toluene oxidation with ozone and the further oxidation of the by-products, thus, 10%MnO2/Y catalyst gave a higher toluene conversion and COx selectivity. With the addition of CuO, the interaction between CuO and MnO2 improved the reduction property of 10%MnO2/Y catalyst and promoted the further oxidation of CO into CO2 with a higher CO2: CO molar ratio. Thus, 5%MnO2-5%CuO/Y catalyst exhibited a high catalytic activity in toluene oxidation with ozone at room temperature with t95 of 240 min, COx selectivity of 80.6% and CO2: CO molar ratio of 4.970. It could be speculated from the results of GC-MS that benzociacid and formic acid phenylmethyl ester as the by-products blocked the catalysts pores and occupied active sites on the surface of the catalysts, resulting in the inactivation of the catalysts.