Study on the Mechanism of Carbon/NO_x Reaction by Using Isotopes

氮氧化物的碳还原已被研究作为一种可能的方法来消除这种污染物涉及臭氧层消耗，酸雨下降和全球变暖。为了获得流化床反应器中发生的基本反应途径，我们研究了碳与NO_x和N_2O的反应机理。使用的主要技术是使用同位素气体的阶跃响应实验。例如，通过将反应物气体从^<15>N^<18>O转换为^<14>N^<16>O，我们可以推测表面^<15>N或表面^<18>O在与^<14>N^<16>O反应时的行为。实验结果表明，C-NO反应中n2的生成主要是C (N)与NO的反应。通过类似的技术，我们也澄清了碳与N_2O之间的反应机理。在碳与^<14>N2^<16>O和^<15>N_2^<16>O的混合物反应过程中，没有观察到^<14>N^<15>N的形成，说明N_2从N_2O中分裂而没有出现N-N键断裂。利用分子轨道计算对这些反应进行了模拟研究，发现上述机理是相当合理的。

Nitrogen oxide reduction with carbon has been studied as a possible way to eliminate this pollutant involved in the ozone layr depletion, acidic rain falls and global warming. In order to obtain the fundamental reaction pathways occurring in the fluidized bed reactor, we have studied the reaction mechanism between carbon and NO_x and N_2O.The principal technique used was the step response experiments using isotope gases. For example, by switching the reactant gas from ^<15>N^<18>O to ^<14>N^<16>O,we can speculate the behavior of surface ^<15>N species or surfhce ^<18>O species during the reaction with ^<14>N^<16>O.From these experiments, it was clearly concluded that the main N_2 formation during C-NO reaction is the reaction between C (N) and NO.By using a similar technique, we also clarified the reaction mechanism between carbon and N_2O.During the reaction of carbon with a mixture of ^<14>N2^<16>O and ^<15>N_2^<16>O,no formation of ^<14>N^<15>N was observed, suggesting the splitting of N_2 from N_2O without N-N bond breakage.The simulation of these reactions were also studied by using molecular orbital calculation, and we found that the above mechanisms are quite reasonable.