Steam CO2 Reforming of Methane over La_(1-x)Ce_xNiO3 Perovskite Catalysts

摘要

La_(1-x)Ce_xNiO3 catalysts were prepared by modified EDTA-cellulose method. The prepared catalysts were characterized by various techniques such as N2 physisorption, TPR, XRD, TPH, TEM-EDS and TG analysis. It was observed that the substitution of Ce resulted in easier reduction of the catalyst. The performance and stability of the catalysts for the steam CO2 reforming of CH4 were investigated under the reaction conditions of 600 ～ 900 °C, 1 bar and feed molar ratio of CH4 : H2O : CO2 = 1 : 1 : 1. It was considered that the substitution of small amount of Ce in the catalyst could activate CH4 and CO2 and it led to higher conversions and Ce02 suppressed carbon formation. However the substitution of large amount of Ce species led to the methanation of CO2 as well as water gas shift reaction. It was found that the conversions of CH4 and CO2 decreased in the following order : La_(0.9)Ce_(0.1)NiO3 > LaNiO3 > La_(0.5)Ce_(0.5)NiO3.