The production of light olefins through carbon oxide hydrogenation represents a promising alternative to fine organic synthesis, where ethylene and propylene are crucial components of the synthesis chain for valuable products. This research focuses on iron-containing Gd1-xAxFeO3 (A=Ca, Sr, Ba) complex oxides as catalysts for simulated bio-syngas hydrogenation. Ca/Sr/Ba-promoted GdFeO3 catalysts were prepared by the sol–gel method and characterized by BET N2-physisorption, X-ray diffraction, and Fourier-transform IR spectroscopy. Their acid–base properties and oxygen non-stoichiometry were also investigated. Their catalytic performances were evaluated in a fixed bed reactor. Ca/Sr/Ba increase the CO conversion rate and ethylene–propylene selectivity, while they decrease the production of methane. A very small amount of A additive can help to enhance the performance of GdFeO3 catalysts in the hydrogenation of carbon oxides. It is worth noting that Ca/Sr/Ba can promote the occurrence of oxygen vacancies and the growth of both acidic and basic centers, and this affects the catalytic properties. With the modification of the Sr promoter, CO conversion and light olefin selectivity both increase due to the increase in the number of catalytically active sites, and they reach their highest values at a silver content of 0.01 wt.%. As a result, Sr can be seen as an attractive candidate to replace more expensive noble metal promoters, such as Pt and Re, under industrial conditions.
The results presented here offer a roadmap for tailoring the distribution of bio-syngas hydrogenation products to specific desired outcomes by adjusting the composition of the catalyst. To fully understand the active sites and phases and to unravel the underlying mechanisms, further in-depth investigations are required given the intricate nature of perovskite-based catalytic systems.
Funding: This work was funded by the Russian Science Foundation, grant № 24-29-00341, https://rscf.ru/project/24-29-00341
