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为研究不同价态的V_2O_5(V_6O_(15)及V_6O_(15)~+)吸附H_2O和NH_3的反应机理,应用量子化学得到反应物、中间体、过渡态和产物的几何构型,对比分析反应过程中优化结构的势能、反应能垒、键长和吸附能等数据.结果表明:V_6O_(15)和V_6O_(15)~+均可吸附H_2O生成V—OH,但是对于后者整个反应表现为放热,而且反应能垒更低,说明V_6O_(15)~+更容易与H2O反应生成BrФnsted酸位;NH_3在V_6O_(15)~+上的吸附能更大,更容易形成可与NO反应的—NH4~+;在SCR脱硝反应中阳离子团簇V_6O_(15)~+比中性团簇V_6O_(15)活性更大.
In order to study the reaction mechanism of V_2O_5 (V_6O_ (15) and V_6O_ (15) ~ +) adsorbing H_2O and NH_3 in different valence states, the geometries of reactants, intermediates, transition states and products were obtained by quantum chemistry. (V_6O_ (15)) and V_6O_ (15) ~ + can all adsorb H_2O to generate V-OH, but for the latter, the whole reaction appears as Which indicates that V_6O_ (15) ~ + is more likely to react with H2O to form BrФnsted acid sites. NH_3 has a larger adsorption energy on V_6O_ (15) ~ + and is more likely to react with NO -NH4 ~ +. In the SCR denitration reaction, the cation cluster V_6O_ (15) ~ + is more active than the neutral cluster V_6O_ (15).