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Combinations of alkaline earth Ba and Sr in place of alkali with Pr and Ce which havestronger oxidation power may result in catalysts with better stability and activity.Studies on theoptimization of Ba-Pr binary system were carried out with catalysts whose Ba/(Ba+Pr)atomic ratio arefrom 0 to 0.56,optimal selectivity was realized at BaPrO_3 which remains the constant reactivity,CH_4conversion 20% and selectivity 57%,during run of 100h at the condition of 1083K aug CH_4:O_2=5:1.Studies on the correlation of reactivity with composition of catalyst demonstrate that there is a synergismbetween basicity and oxidation power.XRD patterns show that Ba and Sr cations insert into lattices ofPrO_(1.8)and CeO_2 respectively,and suppress their combustion power.Kinetic measurements support thesuggestion:the rate-determining-step of title reaction be breaking of C-H bond of methane on PrO_(1.8)phase.
Combinations of alkaline earth Ba and Sr in place of alkali with Pr and Ce which havestronger oxidation power may result in catalysts with better stability and activity. Studies on the optimization of Ba-Pr binary system were carried out with the stated whose Ba / (Ba + Pr ) atomic ratio are from 0 to 0.56, optimality was realized at BaPrO_3 which remains the constant reactivity, CH_4conversion 20% and selectivity 57% during run of 100h at the condition of 1083K aug CH_4: O_2 = 5: 1.Studies on the correlation of reactivity with composition of catalyst demonstrate that there is a synergismbetween basicity and oxidation power. XRD patterns show that Ba and Sr cations insert into lattices of PrO (1.8) and CeO 2 respectively, and suppress their combustion power. Kinetic measurements support the congestion of the rate- determining-step of title reaction be breaking of CH bond of methane on PrO (1.8) phase.