Abstract:

Catalytic oxidation of NO with O₂ over Pt/γ-Al₂O₃ was carried out in a tubular reactor with varying space time(0.090—0.720 s), inlet NO concentration (0.03%—0.2%,vol), O₂ concentration (2%—10%,vol) and at 473—573 K.At 5000 h^-1 space velocity, 0.05% inlet NO concentration and 5% O₂ concentration, the steady-state conversion of NO oxidation increased from 22.4% to 45.5% and 74.3% with temperature increasing from 473 K to 523 K and 573 K.Based on the experimental observations, a mechanism consisting of 12 elementary reactions was proposed, and the kinetic model with the reaction between gaseous NO and dissociately adsorbed O as the rate-limiting step was established and well fitted the experimental data.From the kinetic model, the activation energy of reaction was determined to be 80.01 kJ·mol^-1.

Key words:

一氧化氮, 催化氧化, 负载型铂催化剂, 动力学

摘要：

用连续流动管式反应器考察了在空时为0.090～0.720 s、NO进口浓度为0.03%～0.2%(体积分数)、O₂浓度为2%～10%(体积分数)和温度为473～573 K条件下，NO在Pt/γ-Al₂O₃上的催化氧化反应。结果表明：在空速为5000 h^-1、NO进口浓度为0.05%和O₂浓度为5%条件下，当反应温度从473 K依次升高到523 K和573 K时，NO催化氧化反应的定态转化率从22.4%提高到45.5%和74.3%。NO定态转化率随空时或O₂浓度的增加而增加，但基本与NO的进口浓度无关。基于实验结果和反应动力学理论，提出了含有6对12个正、逆向基元反应的机理，进而确立了以气相NO与解离吸附在催化剂表面的O之间的反应为控制步骤的NO催化氧化总反应速率模型，以其拟合动力学实验数据，确定了动力学参数，得到反应的活化能为80.01 kJ·mol^-1。

关键词:

一氧化氮, 催化氧化, 负载型铂催化剂, 动力学