非贵金属钙钛矿复合氧化物催化剂对NO的直接分解活性研究

摘要

采用溶胶-凝胶方法合成了Cu, Zn, Ni 改性的钙钛矿复合氧化物系列催化剂.X射线衍射分析表明,750 ℃焙烧的此类催化剂在掺杂范围内均具有钙钛矿基本结构.红外光谱分析表明, Cu, Zn, Ni掺入后没改变钙钛矿型的晶体结构,只是随着Cu掺杂量的增加,571 cm-1附近的谱带整体趋势是向波数方向移动.在实验条件下,对NO的活性测试结果表明, La0.9Ce0.1Fe0.8-xCo0.2YxO3(Y=Cu, Zn, Ni)系列催化剂在600～800 ℃范围内,掺杂Cu 的复合氧化物具有较高的催化分解活性,其转化率始终保持在80%以上,反应温度为750 ℃时,几乎100%转化.H2-TPR结果证明,其催化分解活性高的原因是Cu的掺入使晶格氧活动性增强.%Iron-based perovskite-type compounds modified by Cu, Zn, Ni were prepared through sol-gel process to investigate their catalytic activities of NOx direct decomposition. XRD analysis reveals that the samples calcined at 750 ℃ are pure perovskite phase. IR analysis shows that the position and shape of adsorption peaks of almost all of samples are the same except with Cu content increasing, 517 cm-1 peak stretches to high frequency and changes in disorder. Under the experimental conditions, the evaluation of catalytic activity on direct decomposition of NO show that the presence of Cu is necessary for improving activity at 600～800 ℃ among La0.9Ce0.1Fe0.8-xCo0.2YxO3(Y=Cu,Zn,Ni)series, and in which La0.9Ce0.1Fe0.7Co0.2Cu0.1O3 has the highest activity, the conversion of NO decomposition maintains 80% and nearly 100% at 750 ℃. H2-TPR result proves that the higher activity is related to the mobility of lattice oxygen which is beneficial to the reproduction of active site for NO decomposition.