Promotional effect of La2O3 and CeO2 on Ni/gamma-Al2O3 catalysts for CO2 reforming of CH4

作者:Yang Ruiqin; Xing Chuang; Lv Chengxue; Shi Lei; Tsubaki Noritatsu*
来源:Applied Catalysis A: General , 2010, 385(1-2): 92-100.
DOI:10.1016/j.apcata.2010.06.050

摘要

The CO2 reforming reaction of CH4 was conducted by using a Ni-based catalyst prepared by the co-impregnation method. The properties of the catalysts and the carbon deposition performance on the catalyst surface were surveyed by XRD,TPR,TG-DTA, and SEM. The results showed that the activity of the Ni/gamma-Al2O3 catalyst with Ni loading of 10% was higher than that of those with other Ni loadings. However, the Ni/gamma-Al2O3 catalyst was not stable in the continuous reaction due to a large amount of carbon deposition on the catalyst surface. Although the activity of Ni/gamma-Al2O3 with the La2O3 and CeO2 as promoters was not obviously increased, the carbon deposition on Ni/gamma-Al2O3 with La2O3 and CeO2 as promoters was greatly suppressed in the CO2 reforming reaction of CH4. The amount of carbon deposition on the 10%Ni/3%CeO2-3%La2O3-gamma-Al2O3 catalyst was reduced 76.2% compared with the 10%Ni/gamma-Al2O3 catalyst, due to alkaline function and dispersion enhancement of La2O3-CeO2, as well as the electronic interactions between CeO2 and Ni. The results of SEM showed that the moss-like carbon on the 10%Ni/gamma-Al2O3 catalyst was not easily gasified with CO2 and Ni particles, which would result in the catalyst deactivation. On the other hand, the filamentous carbon on the 10%Ni/3%CeO2-3%La2O3-gamma-Al2O3 catalysts could be eliminated readily by gasifying with CO2. Because of the suppression in the sintering of Ni particles and the dominant formation of the reactive filamentous carbon on the Ni-based catalyst that included La2O3 and CeO2 promoters, 10%Ni/3%CeO2-3%La2O3-gamma-Al2O3 catalyst showed stable activity in the continuous CO2 reforming reaction of CH4 at 1073 K and atmospheric pressure.