Modification of Co/TiO₂ for dry reforming of methane at 2 MPa by Pt, Ru or Ni

Influences of an addition of trace amounts of Pt (Pt/Co = 0.005-0.05 in atomic ratio) or Ru (Ru/Co = 0.01-0.05) and of replacement of Co by Ni (Ni:Co = 1:99-100:0) to 0.5wt.% Co/TiO₂ have been investigated for the dry reforming of methane at 2MPa. Co/TiO₂ reduced at 1123K showed slow deactivation due to oxidation of Co. The addition of noble metals improved the catalytic stability of Co/TiO₂ drastically. The strong resistant nature of Co/TiO₂ to coke deposition was also retained by the catalysts. TPR revealed that noble metals improved the reducibility of cobalt oxide. The replacement of Co by a small amount of Ni also enhanced the catalytic stability of Co/TiO₂, but replacement by an excess of Ni resulted in the decrease of catalytic stability because of coking. CoNi/TiO₂ with an optimum Co:Ni ratio of 90:10 presented high stability with only an insignificant amount of coke deposition under 2MPa, where coke deposition is highly favorable.