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储氧量及空燃比对钯催化剂选择氧化CH4和CO的影响
Effect of Oxygen Storage Capacity and Air-fuel Ratio on Selective Oxidation of CH4 and CO for Mixed Oxides Supported Palladium Catalysts
【摘要】 制备了Pd/AlLaZrTiOx(Pd/A),Pd/AlCeZrLaOx(Pd/CZ)和Pd/(AlLaZrTiOx+AlCeZrLaOx)(Pd/CZA)3种催化剂,用热分析仪测试其储氧值(OSC),用红外光谱仪测试在过量空气系数(α)分别为0.8、1.0和1.4时3种催化剂对CH4和CO的选择氧化性能。结果表明,催化剂的储氧性能和空燃比氛围均对CH4和CO的选择氧化性能有较大影响。储氧能力较差的Pd/A和Pd/CZA催化剂在α=1(理论空燃比)时有利于CH4的催化燃烧,在α=1.4(富氧条件)时对CO的完全氧化有利;储氧能力较好的Pd/CZ催化剂对CH4的催化燃烧和CO的完全氧化均在α=1左右时比较有利。贫氧条件下,Pd/CZ催化剂有利于CH4的催化燃烧和CO的完全氧化;富氧条件下,Pd/CZA催化剂有利于CH4的催化燃烧和CO的完全氧化;在理论空燃比附近,Pd/A催化剂对CH4的催化燃烧较好,Pd/CZ催化剂对CO的完全氧化较好。
【Abstract】 Three Pd/AlLaZrTiOx(Pd/A),Pd/AlCeZrLaOx(Pd/CZ) and Pd/(AlLaZrTiOx+ AlCeZrLaOx)(Pd/CZA) catalysts were prepared and their oxygen storage capacity(OSC) was tested by thermogravimetric analyzer(TG).Infrared spectrum analyzer was used to evaluate the selective oxidation performance of CH4 and CO by these catalysts when the excess air coefficient(α) was 0.8,1.0 and 1.4,respectively.The results show that OSC of the catalysts and air-fuel ratio for selective oxidation of CH4 and CO greatly affect the catalytic activity.Pd/A and Pd/CZA catalysts with poor OSC facilitate the catalytic combustion of CH4 at α=1(theory air-fuel ratio) and lead to the complete oxidation of CO atα=1.4(lean burn condition),while Pd/CZ catalyst with good OSC show great catalytic activity when α is about 1.Pd/CZ catalyst should be used for catalytic combustion of CH4 and CO under the condition of the poor oxygen,whereas Pd/CZA catalyst is selected under the condition of rich oxygen or near the theory air-fuel ratio.Pd/A catalyst is more suitable for the catalytic combustion of CH4,however for the oxidation of CO,Pd/CZ shows superiority to Pd/A.
【Key words】 industrial catalysis; Pd catalysts; mixed oxides; methane; CO; air-fuel ratio; oxygen storage capacity; selective oxidation;
- 【文献出处】 贵金属 ,Precious Metals , 编辑部邮箱 ,2015年04期
- 【分类号】O643.36
- 【被引频次】4
- 【下载频次】171