Behavior of GdCoFeO Perovskite-Type Catalysts in the CO-Enriched Syngas Hydrogenation

Complex perovskite-type oxide catalysts GdCoFeO (x = 0;0.2;0.5;0.8;1) were synthesized using by sol-gel technology and studied for their ability to hydrogenate a model biosynthetic gas. X-ray phase analysis (XFA), X-ray photoelectron spectroscopy (XPS), infrared Fourier spectrometry, nitrogen adsorption by the Brunauer-Emmett-Teller (BET) method, and temperature-programmable hydrogen reduction (TPR H) were used to characterize the samples. The nonstoichiometric oxygen content was determined by iodometric titration. The catalytic activity was tested in a reactor with a fixed bed. It was found that the introduction of both Fe and Co into the B-position of the perovskite structure leads to partial reduction of B ions to B, which is compensated for by the formation of oxygen vacancies. The composition of the complex oxides, the number of oxygen vacancies, and the fraction of partially reduced B metal ions all influence the catalytic properties. The synergistic effect in the production of light olefins from a sample with an equal amount of iron and cobalt at the B-position is related to the optimal number of oxygen vacancies and B/B ratio.