Syngas production by combined steam and CO₂ reforming of coke oven gas over highly sinter-stable La-promoted Ni/MgAl₂O₄ catalyst

Highly sinter-stable 10 wt% Ni-xLa/MgAl₂O₄ (x = 0-5 wt%) catalysts were prepared by co-impregnation for the combined steam and CO₂ reforming (CSCR) of coke oven gas (COG). The physicochemical properties of the catalysts were analyzed by BET, XRD, H₂ chemisorption, and H₂-TPR. To compare the sinterstabilities, aging treatment was performed at 900 °C under H₂:H₂O:N₂ = 1:10:1.25 for 50 h. Although the Ni dispersions decrease and Ni crystallite sizes increase for all of catalysts after the aging treatment, the La-promoted catalysts had higher Ni dispersion and smaller crystallite sizes than the Ni/MgAl₂O₄ catalyst owing to the enhancement of strong metal-support interactions. The catalytic test was carried out under CH₄:H₂O:CO₂:H₂:CO:N₂ = 1:1.2:0.4:2:0.3:0.3 at 900 °C and 5 atm for 40 h. The Ni-2.5La/MgAl₂O₄ (aged) catalyst exhibited the highest activity and sinterstability owing to its high surface area and Ni dispersion. It was also confirmed that La promotion prevents the agglomeration of Ni particles through TEM.