Abstract: MgO, TiO2, and Mg0.5Ti0.5Ox composite oxides were prepared by the sol-gel technique. Ni was supported on these oxides by the wet impregnation method. No peak of free NiO was observed in all X-ray diffraction patterns of the catalysts. The addition of Ti to the NiO-MgO system prevents the formation of solid solution but does not decrease the dispersion of Ni particles. The catalytic performance of the catalysts for tri-reforming of methane was investigated in a fixed-bed flow reactor at 850 ℃ under 1.0 MPa with space velocity of 31 800 ml/(g·h) and feed composition of n(CH4)∶n(CO2)∶n(H2O)∶n(O2)=1∶0.48∶0.54∶0.1. The catalytic activity of Ni/TiO2 and Ni/MgO decreases during the reaction period. The Ni/Mg0.5Ti0.5Ox catalyst has a relatively high stability, which is mainly dependent on the moderate interaction between the metal and the support and the moderate ability to be reduced.

Key words: nickel, magnesia, titania, composite oxide, methane, tri-reforming