负载型稀土复合氧化物燃烧催化剂的失活研究

STUDIES ON DEACTIVATION OF SUPPORTED TYPE COMBUSTION CATALYST OF RARE-EARTH COMPOUND OXIDES

本文探讨了负载型稀土复合氧化物燃烧催化剂在使用过程中失活的主要特征.通过XRD,TEM,BET比表面测定及不同使用期的活性测定.证实催化剂在使用后的4—8个月内,烧结是失活的主因;而XPS谱显示硫中毒有积累性,以SO_4^(2-)形式沉积于催化剂表面,构成了燃烧催化剂后期失活的主要因素.由于催化燃烧反应在较高的温度下进行,并充分供氧,所以积炭引起失活的可能性较小,这可以从孔容数据和一些电镜照片中得到证实.

The main characteristics and the causes of deactivation of title catalyst have been investiga-ted. By XRD, TEM and BET, it was shown that deactivation resulted mainly from sintering of catalyst within 4 or 8 months, but the sintering deactivation was relatively unimportant after 8th month. Sulfur which in the form of SO42- had deposited continually on the surface of catalyst was indicated by XPS, resulted in deactivation of sulfur poisoning, and caused major deactivation of combustion catalyst in later working time. Under the condition of catalytic combustion reaction, higher temperature and abundent oxygen, it seems that deactivation of coking should be impossible, which was proved to a certain extent by BET and TEM.