Partial oxidation of methane to syngas over promoted C12A7

Abstract

Partial oxidation of methane into syngas (CO and H 2) was investigated over 12CaO·7Al 2O 3 (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-Al 2O 3 and other calcium aluminates with high CaO/Al 2O 3 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-Al 2O 3, 3CaO·Al 2O 3 (C3A) or CaO·Al 2O 3 (CA), owing to the good dispersion of NiO on C12A7 and the existence of active oxygen ions incorporated in its nanocages.