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根据变换反应机理及钙钛石型化合物的结构特征 ,对La1-xCexFeO3钙钛石无铬高变催化剂进行了设计和制备。DTA和XRD结果表明 :采用机械混合热分解法 ,La1-xCexFeO3钙钛石可在 730～ 76 0℃时生成。活性评价及耐热实验结果表明 :当x≤ 0 5时 ,La1-xCexFeO3(.K)具有较高的热稳定性 ;当x >0 5时 ,在高温变换反应条件下 ,La1-xCexFeO3(.K)将部分或全部转化为铈氧化物和铁氧化物 ,并使催化活性显著降低 ;对于x =0 5的情况 ,在 5 30℃时 ,CO的变换率可高达 6 8%。助剂钾能显著提高低温变换活性 ,同时使高温活性略有降低 ,但对热稳定性几乎没有影响。La0 .5Ce0 .5FeO3(.K)是有开发前景的无铬高变催化剂。
According to the transformation reaction mechanism and the structural characteristics of perovskite-type compounds, La1-xCexFeO3 perovskite high chromium-free catalyst was designed and prepared. The results of DTA and XRD show that La1-xCexFeO3 perovskite can be formed at 730 ~ 76 0 ℃ by mechanical mixed thermal decomposition. The results of the activity evaluation and heat-resistant experiment show that La1-xCexFeO3 (.K) has high thermal stability when x≤0 5. When x> 0 5, La1-xCexFeO3 (.K) K) convert some or all of the cerium oxide and iron oxide, and significantly reduce the catalytic activity; for x = 0 5, the conversion rate of CO can reach as high as 68% at 530 ° C. Potassium additives can significantly improve the low temperature shift activity, while slightly lower the high temperature activity, but almost no effect on thermal stability. La0 .5Ce0 .5FeO3 (.K) is a promising chromium-free catalyst.