KINETIC-STUDIES OF NO REDUCTION BY CH4 OVER NONMETALLIC CATALYSTS

NO reduction by CH4 was conducted over MgO, 1% Li/MgO, 4% Li/MgO, 16% Li/MgO, and La2O3 between 773 and 973 K. The specific activities of N-2 formation (mu mol N-2/s . m(2)) over the Li/MgO samples were almost 5 times higher than that over pure MgO, and La2O3 was much more active than Li/MgO catalysts. E(act) values for the Li/MgO catalysts were 29.0+/-1.1 and 35.0+/-1.0 kcal/mol in the absence and presence of O-2, respectively, while they were 24.4 and 26.0 kcal/mol for La2O3. Li/MgO had a negative reaction order of -0.5 in O-2 at 923K, whereas a positive 0.5 order in O-2 existed for La2O3. For the Li/MgO catalysts the reaction orders on CH4 and NO were near 0.7 and 0.4, respectively, while they were about 0.3 and 1.0 for La2O3.