不同Cu负载量Cu-ZSM-5催化剂上正丁胺的选择催化氧化性能

采用等体积浸渍法制备不同Cu负载量(1%、2%、5%和10%)的系列Cu-ZSM-5催化剂,并考察了Cu负载量对催化剂的正丁胺催化氧化性能的影响。通过XRD、N₂吸脱附、EPR、H₂-TPR、NH₃-TPD表征方法对催化剂的晶相结构和物化性质进行表征并研究构效关系。结果表明:Cu负载量为10%的催化剂催化活性最高,在300℃下实现了正丁胺的完全转化;而Cu负载量为5%的催化剂N₂选择性最佳,低温时N₂选择性明显高于其他催化剂。表征结果表明,催化剂的氧化还原性能主要影响正丁胺的转化率,Cu负载量影响催化材料的氧化还原性能,Cu负载量高的催化剂氧化还原性能优异。高N₂选择性主要归属于催化剂孤立态Cu2+物种和弱酸性位,催化剂的弱酸性位有利于正丁胺的吸附活化和深度氧化。

SELECTIVE CATALYTIC OXIDATION PERFORMANCE OF N-BUTYLAMINE OVER Cu-ZSM-5 CATALYSTS WITH DIFFERENT COPPER LOADINGS

A series of Cu-ZSM-5 catalysts with different Cu loadings (1%, 2%, 5% and 10%) were synthesized by equal volume impregnation method, and the effect of Cu loading on n-butylamine catalytic oxidation was investigated. The crystal structure and physicochemical properties of the catalysts were characterized by XRD, N₂ adsorption desorption, EPR, H₂-TPR and NH₃-TPD, and the structure-activity relationship was studied. The catalyst with Cu loading of 10% had the highest catalytic activity, and the complete conversion of n-butylamine was achieved at 300℃. The catalyst with 5% Cu loading had the best N₂ selectivity, and the N₂ selectivity at low temperature was significantly higher than that of the other catalysts. The characterization results showed that the redox performance of the catalyst mainly affected the n-butylamine conversion, the different Cu loading affected the redox performance of the catalyst materials, and the catalyst with higher Cu loading had excellent redox performance. The high N₂ selectivity could be attributed to the isolated Cu2+ species and the weak acid sites of the catalyst, which was conducive to the adsorption activation and deep oxidation of n-butylamine to form N₂.