Performance of CaO-Promoted Ni Catalysts over Nanostructured CeO2 in Dry Reforming of Methane

Ni (20 wt.%) catalysts supported on CeO2 were synthesized using the incipient wetness impregnation method and promoted with varying amounts of CaO (0, 5, 10, 15, 20 wt.%). The catalysts were evaluated in dry reforming of methane (DRM) at 650 degrees C for 24 h. Fresh catalysts were characterized by XRD, WD-XRF, H2-TPR, N2 physisorption, HDP, SEM, and FT-IR spectroscopy (DRIFT and ATR), while spent catalysts were characterized by XRD, Raman spectroscopy, and SEM. The incorporation of 5-15 wt.% CaO on CeO2 significantly improved its catalytic performance. FT-IR analysis confirmed the presence of CaCO3 bands, indicating carbonate formation. The Ni/CeO2 catalyst with 15 wt.% CaO exhibited the highest catalytic activity. The promoted catalysts demonstrated high stability, attributed to strong interactions between CeO2, CaO, and CaCO3. However, when CaO promotion reached 20 wt.%, catalytic activity decreased. Despite large carbon formations, the catalysts maintained their stability with no significant deactivation due to sintering or coke accumulation.