Effects of various barium precursors and promoters on catalytic activity of Ba–Ti perovskite catalysts for oxidative coupling of methane

The influences of barium precursor and promoter type on the catalytic performance of perovskite catalysts in OCM reaction were studied. Catalysts (BaTiPO3, P: promoter) were prepared by carbonate, hydroxide and propionate precursors of barium and SnCl2 and CeO2 as promoters by sol–gel method, tested in a fixed-bed microreactor and characterized by XRD, BET, CO2-TPD, FT-IR and UV–Visible analysis. The experiment results showed that based on the extent of effect upon catalyst efficiency, the barium anions can be ranked as; propionate > carbonate > hydroxide, and the CeO2 promoted catalysts were more active than the SnCl2 promoted ones. The characterization results showed that the substitution of metal precursors caused formation of different phases with different particle sizes, influenced the basicity of the catalysts, resulted in the appearance of the peaks corresponding to different groups in IR spectroscopy, and shifted the absorption peaks in UV–Visible spectra. These results suggested that OCM reaction over perovskite catalysts is structure sensitive and depended on the type of used precursor and promoter.