Abstract

Mixed oxides 1%Cs/Mg_xCo_3–xO₄ (х = 0–0.9) with a spinel structure are synthesized by precipitation from nitrate solutions using (NH₄)₂CO₃ as the precipitating agent and the subsequent modification of the dry precipitate with cesium by the Pechini method and calcining. The synthesized samples are studied by XRD, BET, SEM, TPR, and TPD methods. It is shown that an increase in the magnesium content leads to a significant decrease in the degree of crystallization of the oxides, an increase in the specific surface area, and the formation of loosely bound oxygen species, which contributes to an increase in the catalytic activity of the samples in nitrous oxide decomposition at temperatures of 150–400°С. The highest activity is exhibited by the 1%Cs/Mg_0.1Co_2.9O₄ catalyst characterized by the presence of the maximum amount of loosely bound oxygen species. It is shown that the presence of oxygen or water in the reaction mixture leads to a decrease in the catalyst activity at 250°C by 10 or 80%, respectively; after that, the catalyst exhibits a stable on-stream behavior for at least 25 h. The catalyst activity is restored after a heat treatment.

中文翻译：

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1％Cs / Mg x Co 3–x O 4（x = 0–0.9）氧化物下一氧化二氮的低温分解

摘要

尖晶石结构的混合氧化物1％Cs / Mg _x Co _{3– x} O ₄（х = 0–0.9）通过使用（NH ₄）₂ CO ₃从硝酸盐溶液中沉淀而合成作为沉淀剂，随后通过Pechini方法和煅烧将干燥的沉淀物用铯改性。通过XRD，BET，SEM，TPR和TPD方法研究合成的样品。结果表明，镁含量的增加会导致氧化物结晶度的显着下降，比表面积的增加以及形成松散结合的氧种类，从而有助于催化活性的提高。样品在150–400°С温度下分解产生的一氧化二氮。1％Cs / Mg _0.1 Co _2.9 O ₄表现出最高的活性该催化剂的特征在于存在最大量的松散结合的氧。结果表明，反应混合物中氧气或水的存在导致催化剂活性在250℃下分别降低了10％或80％。之后，该催化剂在至少25小时内表现出稳定的运行状态。热处理后，催化剂活性恢复。