New nanostructured perovskite-type catalysts for light olefins production

Perovskite-type structures with mixed oxygen-ionic and electronic conductivity, high activity and stability are used as catalysts for high temperature processes such as synthesis gas production and ethylene and propylene subsequent synthesis. The nanostructured perovskite-type oxides GdFe1-xMnxO3 (x = 0, 0.01, 0.05, 0.2, 0.5, 0.8 and 1) were synthesized by ceramic and sol-gel technologies and were studied as catalysts for dry reforming of methane and the CO hydrogenation. The complex of physico-chemical investigation methods showed that samples obtained by sol-gel technology are in nanocrystalline state and these have a porous structure, and oxides prepared by ceramic technology are in sub-microcrystalline state. The sol-gel method makes it possible to obtain samples with higher catalytic performances in comparison with ceramic systems. Doping the B-site of gadolinium ferrites with manganese, and also surface modification with Mn leads to an increase in olefin selectivity over the entire temperature range. The highest stability, catalytic activity, and unsaturated hydrocarbons (ethylene and propylene) selectivity in the carbon oxides hydrogenation were observed over GdFeO3, GdFe0.95Mn0.05O3, 5 %wt Mn/GdFeO3 samples. It was established that the phase composition of all ferrites remains unchanged after catalytic reactions. Partial decomposition of catalysts and significant changes in the samples morphology didn’t occur. Carbon is present on the used catalysts surface, but since the catalysts activity didn't change in repeated experiments for a long time, it is suggested that this carbon is mostly active. And formation of inactive carbon for samples obtained by sol-gel method is minimal. © 2018 TANGER Ltd. All Rights Reserved.