Abstract: The Ni/Al2O3 catalyst calcined at ultrahigh temperatures (1200-1400 ℃) was used in partial oxidation of methane (POM), and the Ni/Al2O3 catalyst retained high activity for POM after reduction. TheX-raydiffraction result indicated that NiAl2O4 was formed when the catalyst was calcined at ultrahigh temperatures, and there was no phase transition in the temperature range. After the catalyst was reduced by H2 at 950 ℃, most of Ni in the catalyst existed as Ni0, and the crystal size of Ni0 was similar, which was confirmed by transmission electron microscopy. The excellent performance of the Ni/Al2O3 catalyst calcined at ultrahigh temperatures for the POM reaction was attributed to both the reducibility of NiAl2O4 and the similar crystal size of Ni0. The higher the calcination temperature, the higher the reduction temperature for NiAl2O4.

Key words: nickel, alumina, supported catalyst, ultrahigh temperature calcination, methane, partial oxidation, reduction