N_2O在钾改性Cu-Co尖晶石型复合氧化物上的催化分解(英文)

制备了几个不同组成的Cu-Co尖晶石型复合氧化物,用于N2O分解反应,在活性较高的Cu0.8Co0.2Co2O4表面浸渍碱金属盐溶液,制备改性催化剂,考察了碱金属助剂类型、钾前驱物和钾负载量等对改性催化剂活性的影响。用BET、XRD、SEM、XPS等方法表征了催化剂结构。结果表明,几种碱金属碳酸盐改性Cu0.8Co0.2Co2O4的催化活性发生了显著变化,其中,K改性催化剂的活性有明显提高,而Cs的表面改性反而降低了催化剂活性;钾前驱物对K/Cu-Co的催化活性也有较大影响,其中,加入碳酸钾明显提高了催化剂的活性,而加入硝酸钾和醋酸钾反而降低了催化剂活性;有氧无水、有氧有水气氛中,400!C下N2O在碳酸钾改性催化剂0.05K/Cu0.8Co0.2Co2O4上的转化率分别达到了100%和87.6%;该催化剂在400!C下的恒温反应活性和稳定性均高于未改性催化剂。

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.