Influence of the reduction temperature on catalytic activity of Co/TiO2 (anatase-type) for high pressure dry reforming of methane

0.5 wt.% Co/TiO2 was prepared by incipient wetness impregnation with Co(NO3)(2)(.)6H(2)O and TiO2, which contains only anatase as crystal structure. The influence of reduction temperature (973-1223 K) on the catalytic activity of the 0.5 wt.% Co/TiO2 was investigated for the CH4/CO2 reaction under 2.0 MPa mainly at a space velocity (SV) of 6000 ml g(-1) h(-1). Co/TiO2 reduced below 1123 K lost its activity completely at the beginning of the reaction. The results of TPO revealed that large amounts of coke (greater than or equal to2.9 wt.% carbon for 24 h) were deposited on the catalysts during the CH4/CO2 reaction. On the other hand, Co/TiO2 reduced at and above 1123 K kept relatively stable activity for 24 h and did not show significant amounts of deposited coke (less than or equal to0.25 wt.% carbon). The natures causing different catalytic behavior among the catalysts were discussed with the results of TEM, XRD, and TPR. In addition, slow deactivation of the Co/TiO2 reduced at 1123 K, probably due to the oxidation of the metallic cobalt, was inhibited by the addition of small amount of ruthenium (Ru/Co = 0.05) and it was found that the strong resistance to the coking of the Co/TiO2 reduced at 1123 K was retained after the addition of ruthenium. (C) 2003 Elsevier B.V. All rights reserved.