Sang Chimin, Kim Bryan H, Lund Carl R F
Department of Chemical and Biological Engineering, University at Buffalo, SUNY, Buffalo, New York 14260-4200, USA.
J Phys Chem B. 2005 Feb 17;109(6):2295-301. doi: 10.1021/jp048884m.
An Fe/ZSM-5 catalyst with a very high Si/Al ratio was prepared, and using it, the effect of NO upon the kinetics of N2O decomposition was studied. The addition of small, nonstoichiometric amounts of NO was observed to cause the rate to increase by more than an order of magnitude. The kinetics were well-fit by a rate expression that was first order in the partial pressure of N2O for the situation without added NO and separately for the situation where NO was added. The Arrhenius parameters of the rate coefficient differed for the two situations. The results are consistent with a mechanistic scheme wherein the reaction proceeds via an oxide-oxo redox cycle in the absence of NO. The results suggest that the NO-assisted decomposition of N2O does not require a second iron site adjacent to the active site and that NOx species adsorbed on the same cation site could serve as locations for oxygen storage if, in fact, the promotional effect of NO is related to such storage.
制备了具有非常高硅铝比的铁/ ZSM - 5催化剂，并以此研究了NO对N2O分解动力学的影响。观察到添加少量非化学计量的NO会使反应速率提高一个多数量级以上。对于未添加NO的情况以及添加NO的情况，动力学都能很好地拟合为N2O分压的一级速率表达式。两种情况下速率系数的阿伦尼乌斯参数不同。结果与一种机理方案一致，即在没有NO的情况下反应通过氧化 - 氧氧化还原循环进行。结果表明，N2O的NO辅助分解不需要与活性位点相邻的第二个铁位点，并且如果NO的促进作用实际上与这种氧储存有关，那么吸附在同一阳离子位点上的NOx物种可以作为氧储存的位置。
