与不同氧化物复合的La0．8Ca0．2FeO3钙钛矿用于低浓度甲烷的催化燃烧

Catalytic lean burn of methane in air by La_(0.8)Ca_(0.2)FeO_3 perovskites composited with different oxides

用沉淀沉积法制备了沉积在YSZ、GDC和MgO 3种载体上的La0.8Ca0.2FeO3(La8Ca2)钙钛矿复合催化剂,在程序升温反应和质谱联用仪中考察其对低体积分数甲烷(1%)的催化燃烧反应活性。用SEM、BET、XRD对其物理化学性质进行表征。实验发现,不同载体的最佳摩尔比例分别为La8Ca2/7YSZ、La8Ca2/6GDC和La8Ca2/4MgO。3种载体均能提高钙钛矿的催化活性和热稳定性,YSZ和GDC因与La8Ca2存在相互作用,能成倍提高催化剂活性;3种载体中,MgO抗烧结能力最强,YSZ热稳定性最差,但仍高于La8Ca2。

La0.8 Ca0. 2FeO3 （La8Ca2） perovskites supported on YSZ （ Yttria Stabilized Zireonia）, GDC （ Gadolinia Doped Ceria） and MgO have been prepared by deposition-precipitation method and tested in catalytic lean burn of methane （1 vol. % diluted by air）. The temperature programmed reaction-mass spectroscopy is applied to screen the best molar ratio of support to catalyst. All the catalysts are characterized by SEM, BET and XRD. It is found that the best ratios are La8Ca2/7YSZ, La8Ca2/6GDC and La8Ca2/4MgO, respectively. All the supports have improved activity and stability of LaSCa2. The activity has been increased by several folds due to the interaction of YSZ or GDC with La8Ca2. Among the three supports, MgO shows the highest thermal stability. YSZ, which is the least stable to heat, is still better than La8Ca2 itself at high temperature.