THERMOGRAVIMETRIC STUDY IN CONNECTION WITH THE CO2-REFORMING REACTIONOF CH4

Different types of Ni catalysts were examined for the CO2-reforming re action of CH4 to give syngas. The activity was in the sequence: Ni/MgO +SiO2 > Ni/MgO similar to Ni/MgO+MgO > Ni/SiO2 similar to NiO+MgO. The lifetimes of endurance tests at 800 OC were in the sequence: Ni/MgO+S iO2 > Ni/MgO. It was deduced from these results that MgO acting as a s upport accelerated the reaction in connection with the dissociatively adsorbed species CHX(a), but didn't accelerate the reaction as a mixtu re. On the contrary, SiO2 accelerated the reaction as a mixture, but d idn't do so as a support. TGA tests showed that physically mixed SiO2 diminish the amount of deposited carbon. It was discussed that CHX(a) having a large X value, which was produced over Ni which was supported on a basic support or over the Ni catalyst having a large amount of s pillover hydrogen, was active in the reaction.