摘要
用Mossbauer,IR等技术及对样品磁化率与电导率的测量,研究了钙钛石型复合氧化物La_(1-x)Sr_xFeO_(3-λ)体系中,活性金属铁离子在改变x时的价态和配位环境的变化及其对催化活性的影响。发现催化剂在0≤x<0.5～0.7范围内,其Fe—O键的相互作用较强,催化活性主要由催化剂的表面化学所控制;在0.7≤x≤1.0范围内,催化剂中Fe-O键相互作用减弱,氧空位出现有序化,在这一范围内,催化活性主要由催化剂的体相化学控制。
The State of iron ion, which is ihc calalytically active component in pcro-vskitc type catalysis I a1-xSrxFeO3-. as well as its effect on catalytic activity for NH3 oxidation were studied by Mossbauer and infrared speclroscopy, and the measurements of magnetic susceptibility and electrical conductivity.It was found that the interaction of Fc with O in Fe-O bond was strong in the range of 0≤x<0.5-0.7, and the catalytic activity could be attributed to the surface chemistry of the catalysis in this range. Comparatively, the interaction between Fe and O in Fe-O bond was weakened and the oxygen vacancy ordering appeared at 0.7≤x≤1.0, and in this range the catalytic activity was determined by the bulk chemistry of the catalysts.
