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

• Syngas was produced by combined steam and CO2 reforming (CSCR) of coke oven gas (COG).
• Highly sinter-stable Ni–La/MgAl2O4 catalysts were prepared by the co-impregnation.
• La promotion significantly enhanced the SMSIs and suppressed the Ni particle sintering.
• Ni–xLa/MgAl2O4(aged) showed higher Ni dispersion and smaller Ni size than Ni/MgAl2O4(aged).
• Ni–2.5La/MgAl2O4 (aged) catalyst has the best catalytic activity and sinterstability.

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.