Effect of preparation route on Sr₂TiO₄ catalyst for the oxidative coupling of methane

Four different preparation routes were used to synthesize Sr₂TiO₄ with the structure of layered perovskite: sol-precipitation (SP), co-precipitation (CO), citrate precursor (CT) and mechanochemical (MA) methods with further calcinations at 1100 °C. The XDR, XPS, BET, SEM techniques showed that the different preparation routes caused the formation of layered perovskite phase with different admixture phases, particle sizes and the surface enrichment with layered perovskite (for SP and MA samples) or strontium oxide (for CO and CT samples). The trend of increasing of CH₄ conversion and C₂-yield in oxidative coupling of methane at 800-900 °C was found to be the following: SP≈MA > CO > CT samples. The C₂-yield of the most active catalysts was measured to be about 12%.