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制备了用于氨氧化制硝酸的含重稀土和钴的复合氧化物催化剂。研究了几种不同的载体和它们的几何形状对催化剂活性的影响。测定了板状催化剂的传质因素。用X射线电子能谱、热重分析等方法比较了复合氧化物和Co_3O_4催化剂的反应稳定性。结果表明,用α-Al_2O_3载体制备的多孔板状催化剂与粒状和蜂窝状催化剂相比具有比表面积大,表面反应性能好等特点。复合氧化物催化剂较Co_3O_4催化剂具有更好的反应稳定性,其原因主要是复合氧化物具有稳定的晶相结构和Co~(3+)活性中心离子。
Preparation of a catalyst for the oxidation of nitric acid containing heavy rare earth and cobalt composite oxide catalyst. The effect of several different supports and their geometry on the catalyst activity was investigated. The mass transfer factors of the plate-shaped catalyst were measured. The reaction stability of the composite oxide and Co_3O_4 catalyst was compared by X-ray photoelectron spectroscopy and thermogravimetric analysis. The results show that the porous plate catalysts prepared with α-Al 2 O 3 support have the advantages of large specific surface area and good surface reactivity compared with granular and honeycomb catalysts. The composite oxide catalyst has better reaction stability than Co_3O_4 catalyst because the composite oxide has a stable crystalline phase structure and Co 3+ active center ions.