Catalytic decomposition of N₂O over potassium-modified Cu-Co spinel oxides

Cu-Co spinel oxides with different compositions were prepared for N₂O catalytic decomposition in the presence of oxygen. The active catalyst of Cu_0.8Co_0.2Co₂O₄ was incipiently impregnated by alkali metal salt solutions to prepare the modified catalysts. These catalysts were characterized by BET, XRD, SEM and XPS techniques, and their catalytic activity for N₂O decomposition was tested. The effect of alkali metal species, potassium precursors and potassium loadings on catalytic activity was investigated. It was found that the catalytic activity of Cu_0.8Co_0.2Co₂O₄ modified by K₂CO₃ was much higher than that of bare oxide, while Cs/Cu_0.8Co_0.2Co₂O₄ was inferior to Cu_0.8Co_0.2Co₂O₄ for N₂O decomposition. In the case of K/Cu_0.8Co_0.2Co₂O₄ with different potassium precursors, the catalyst activity was largely enhanced by the addition of K₂CO₃, while the doping of KNO₃ and CH₃COOK notably depressed the catalytic activity. Over the optimal catalyst of 0.05K/Cu_0.8Co_0.2Co₂O₄, 100% and 87.6% conversion of N₂O was reached at 400 SymbolpB@ C under the atmosphere of oxygen only and oxygen-steam together, respectively. In addition, K₂CO₃-modified catalyst in both reaction atmospheres showed higher stability than un-modified catalyst.