不同硅铝比Cu-ZSM-5纳米片上N_2O催化分解

Catalytic Decomposition of N_2O over Cu-ZSM-5 Nanosheets with Different n_(Si)/ n_(Al)

以双季铵盐表面活性剂为模板剂,水热条件下合成了硅铝比(nSi/nAl)为18、26和95的ZSM-5沸石纳米片,采用离子交换方法制备了铜改性的ZSM-5纳米片样品,并测试了其催化分解N_2O性能。结合X射线衍射(XRD)、N_2吸附/脱附、X射线荧光光谱(XRF)、扫描电镜(SEM)、透射电镜(TEM)、氢气程序升温还原(H_2-TPR)、氧气程序升温脱附(O_2-TPD)和原位红外漫反射光谱(CODRIFT)等表征结果 ,探讨了沸石硅铝比对于催化剂N_2O分解性能的影响及其原因。结果表明,ZSM-5纳米片硅铝比越低,CuZSM-5纳米片催化剂的活性越高。催化活性的提高归因于低硅铝比催化剂上Cu^+活性物种可还原性的增强和吸附氧脱附能力的提高。

ZSM-5 nanosheets with Si/Al molar ratios of 18, 26 and 95 have been synthesized hydrothermally using[C18H37-N＋（CH3）2-C6H12-N＋（CH3）2-C6H13]Br2 as a template and then ion-exchanged with Cu2＋cations. The obtained CuZSM-5 nanosheets were characterized by XRF, N2 adsorption-desorption, XRD, SEM, TEM, DRIFTS, H2-TPR, O2-TPD and CO-DRIFT. Their catalytic performance for N2 O decomposition was investigated. The catalytic activity in terms of TOF for Cu-ZSM-5 nanosheets increases with the decreasing of the nSi/ nAl, due to better reducibility of active Cu＋species, and better desorption capability of adsorbed oxygen on Cu-ZSM-5 nanosheets with lower nSi/ nAl.