Ni/M-Al2O3 (M=Sm, Ce or Mg) for combined steam and CO2 reforming of CH4 from coke oven gas

Effects of structural promoters such as Sm, Ce, Mg metal oxides on the Ni/M-Al2O3 catalysts (where M = Sm, Ce, or Mg) were verified to elucidate different catalytic activity for a combined steam and CO2 reforming reaction with CH4 (CSCR) using H-2-rich coke oven gases generated from steel industry. The enhanced catalytic performance and stability were explained in terms of the variations of surface basic sites with different aggregation phenomena of active nickel crystallites and resistances for a coke formation. The most efficient Sm promoter having a high electronegativity and basic property on the Ni/M-Al2O3 was found to largely suppress a coke deposition and less aggregation of active nickel crystallites by forming the strongly interacted nickel nanoparticles with an enhanced basic sites on the Sm-modified Al2O3. In addition, a larger amount of basic sites on the Ni/Sm-Al2O3 were responsible for a less coke deposition and best catalytic performances in terms of the conversions of CH4 and CO2. These positive effects of Sm promoter were also attributed to a relatively easy activation of CO2 and the formation of the strongly interacted smaller nickel crystallites on the newly formed basic perovskite-like SmAlO3 structures or segregated Sm2O3 species.