Abstract :
Partial oxidation of methane into syngas (CO and H2) was investigated over 12CaO·7Al2O3 (C12A7) promoted by metals such as Ni, Co, Pt, Pd and Ru. The effect of space velocity and metal loading was studied, and the catalytic behavior of Ni/C12A7 was compared with nickel catalysts supported on CaO, α-Al2O3 and other calcium aluminates with high CaO/Al2O3 ratio. On Ni, Pt and Pd/C12A7, this reaction readily happened at temperatures as low as 500 °C and attained thermodynamic equilibrium. Five samples were investigated at 800 °C and at a space velocity of 240,000 ml g−1 h−1. Their activity values decreased in the following order: 1% Pt/C12A7 > 5% Co/C12A7 > 5% Ni/C12A7 > 1% Ru/C12A7 > 1% Pd/C12A7. The activity and selectivity of Ni/C12A7 and Pt/C12A7 increased with metal loading, and the activity of 10% Ni/C12A7 has been comparable to that of 1% Pt/C12A7. Ni/C12A7 exhibited low coke formation rate and the material was more active than nickel supported on CaO, α-Al2O3, 3CaO·Al2O3 (C3A) or CaO·Al2O3 (CA), owing to the good dispersion of NiO on C12A7 and the existence of active oxygen ions incorporated in its nanocages.
