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在K/MgAlO催化剂上测试了气态及吸附态NO2与碳烟(soot)的反应,结合原位红外表征和第一性原理计算确认了反应中间物,对两类反应的差异进行了机理解析.结果表明,吸附态NO2的活性弱于气态NO2.吸附态NO2以硝酸盐的形式参与反应,导致出现了2个红外特征峰2234和2110 cm-1,分别归属为K位上的氰酸离子和MgAlO载体上的氰离子.此外,气态NO2的反应中间物异氰酸离子也得到证实.吸附态NO2(即硝酸盐)的反应受到K+静电场的束缚,倾向于形成氰酸离子,氰酸离子易裂解成氰离子迁移到载体上;气态NO2与碳烟反应则倾向于形成相对稳定的异氰酸离子.吸附态NO2较弱的低温活性可归因于K+静电场的束缚.
The reaction of gaseous and adsorbed NO2 with soot was tested on K / MgAlO catalyst. The reaction intermediates were confirmed by in situ infrared characterization and first principles calculations, and the differences between the two types of reactions were analyzed. The results showed that the activity of adsorbed NO2 was weaker than that of gaseous NO2. The adsorbed NO2 participated in the reaction as nitrate, resulting in two infrared characteristic peaks of 2234 and 2110 cm-1, which belonged to cyanate ions at K In addition, the reaction of gaseous NO2 is also confirmed as isocyanic acid ion.The reaction of adsorbed NO2 (ie, nitrate) is bound by K + electrostatic field, which tends to form cyanate ion, cyanate ion The reaction of gaseous NO2 with soot tends to form relatively stable isocyanates. The weak activity of adsorbed NO2 can be attributed to the binding of K + electrostatic field.