氢气还原硝酸盐的理论研究

从烟气中NO_x在吸附剂表面形成硝酸盐的事实出发，结合理论计算研究了硝酸盐被还原的微观反应过程。以H₂为还原剂、Al(NO₃)₃为模型化合物，采用密度泛函方法得到的计算结果显示，H₂还原Al(NO₃)₃的反应是分步进行的，H₂吸收热量，解离成H·，H·将Al(NO₃)₃还原为Al(OH)₃和NO，然后NO进入气相与H₂反应生成N₂。H₂解离成H·的反应需要445.43 kJ/mol的能量，翻越反应能垒需要586.80 kJ/mol，是整个反应的控速步骤。除H₂离解形成H·反应之外的其余步骤均为放热反应。

Theoretical Study on Hydrogen Reduction of Nitrate

From the fact that the NO_x in flue gas was adsorbed on the surface of adsorbents in the form of nitrate, the micro mechanism of H₂ reduction of nitrate was studied with theoretical calculations by using density functional method, in which H₂ was used as reducing agent, Al(NO₃)₃ as model compound. The results of thermodynamics and dynamics indicated that the procedures of H₂ reduction of nitrate were performed by separated steps. Firstly, the H₂ absorbed heat and decomposed into hydrogen radical (H·). Then Al(NO₃)₃ reacted with H· and converted into Al(OH)₃ and NO. Finally NO was reducted by H₂ to N₂ in gas stream. The reaction energy of H₂ to H· was 445.43 kJ/mol with the energy barrier of 586.80 kJ/mol, so the conversion of H₂ to H·was the key step in the reduction, apart from which the remaining steps were exothermic reactions.