Catalysis Letters, Vol.149, No.9, 2563-2574, 2019
Ni Based Catalysts Supported on Ce Modified MgAl Spinel Supports for High Temperature Syngas Methanation
A series of highly dispersed nickel (Ni)-based catalysts supported on cerium (Ce)-modified high surface area magnesium-aluminum (MgAl) spinel support were prepared via a coprecipitation and impregnation method for high temperature syngas methanation. The influence of Ce substitution on the catalyst's textural property were investigated via characterization by BET, XRD, TEM, H-2-TPR, XPS, H-2-TPD, and CO-TPD. The appropriate Ce species addition significantly increased catalyst surface area, improved active metal dispersion, and retained moderate interactions between NiO and support, which in turn enhanced Ni availability and suppressed aggregation. Meanwhile, the surface Ni-0 concentration and oxygen vacancy number was improved, leading to easier dissociation for carbon monoxide (CO), which significantly contributed to high temperature methanation. Among all catalysts, Ni/MgAl-5Ce achieved the best catalytic performance at 500 degrees C, 2.0MPa, and 30,000mlg(-1)min(-1), with CO conversion, CO2 conversion, and CH4 selectivity at 99.2, 42.7, and 98.9%, respectively. Furthermore, Ni/MgAl-5Ce maintained excellent stability during a 50h life test. [GRAPHICS] .