Co and Ni supported on CeO2 as selective bimetallic catalyst for dry reforming of methane

Co/CeO2 (Co 7.5 wt.%), Ni/CeO2 (Ni 7.5 wt.%) and Co-Ni/CeO2 (Co 3.75 wt.%, Ni 3.75 wt.%) catalysts were prepared by surfactant assisted co-precipitation method. Samples were characterized by XRD, BET, TPR and tested for the dry reforming of methane CH4 + CO2  2CO + 2H2 in the temperature range 600-800 °C with a CH4:CO2:Ar 20:20:60 vol.% feed mixture and a total flow rate of 50 cm3 min-1 (GHSW = 30000 mL g-1 h-1). The bimetallic Co-Ni/CeO2 catalyst showed higher CH4 conversion in comparison with monometallic systems in the whole temperature range, being 50% at 600 °C and 97% at 800 °C. H2/CO selectivity decreased in the following order: Co-Ni/CeO2 > Ni/CeO2 > Co/CeO2. Carbon deposition on spent catalysts was analyzed by TG-DTA analysis. After 20 hours under stream at 750 °C, cobalt-containing catalysts, Co/CeO2 and Co- Ni/CeO2, showed a stable operation in presence of a deposited amorphous carbon of 6 wt.%, whereas Ni/CeO2 showed an 8% decrease of catalytic activity due to a massive presence of amorphous and graphitic carbon (25 wt.%).