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CO 2 is the most cost-effective and abundant carbon resource, while the reverse water–gas reaction (rWGS) is one of the most effective methods of CO 2 utilization. This work presents a comparative study of rWGS activity for perovskite systems based on AFeO 3 (where A = Ce, La, Y). These systems were synthesized by solution combustion synthesis (SCS) with different ratios of fuel (glycine) and oxidizer ( φ ), different amounts of NH 4 NO 3 , and the addition of alumina or silica as supports. Various techniques, including X-ray diffraction analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, energy-dispersive X-ray spectroscopy, N 2 -physisorption, H 2 temperature-programmed reduction, temperature-programmed desorption of H 2 and CO 2 , Raman spectroscopy, and in situ FTIR, were used to relate the physicochemical properties with the catalytic performance of the obtained composites. Each specific perovskite-containing system (either bulk or supported) has its own optimal φ and NH 4 NO 3 amount to achieve the highest yield and dispersion of the perovskite phase. Among all synthesized systems, bulk SCS-derived La–Fe–O systems showed the highest resistance to reducing environments and the easiest hydrogen desorption, outperforming La–Fe–O produced by solgel combustion (SGC). CO 2 conversion into CO at 600 °C for bulk ferrite systems, depending on the A-cation type and preparation method, follows the order La (SGC) < Y < Ce < La (SCS). The differences in properties between La–Fe–O obtained by the SCS and SGC methods can be attributed to different ratios of oxygen and lanthanum vacancy contributions, hydroxyl coverage, morphology, and free iron oxide presence. In situ FTIR data revealed that CO 2 hydrogenation occurs through formates generated under reaction conditions on the bulk system based on La–Fe–O, obtained by the SCS method. γ -Al 2 O 3 improves the dispersion of CeFeO 3 and LaFeO 3 phases, the specific surface area, and the quantity of adsorbed H 2 and CO 2 . This led to a significant increase in CO 2 conversion for supported CeFeO 3 but not for the La-based system compared to bulk and SiO 2 -supported perovskite catalysts. However, adding alumina increased the activity per mass for both Ce- and La-based perovskite systems, reducing the amount of rare-earth components in the catalyst and thereby lowering the cost without substantially compromising stability.

Rare-earth orthoferrites have found wide application in thermocatalytic reduction-oxidation processes. Much less attention has been paid, however, to the production of CeFeO3, as well as to the study of its physicochemical and catalytic properties, in particular, in the promising process of CO2 utilization by hydrogenation to CO and hydrocarbons. This study presents the results of a study on the synthesis of CeFeO3 by solution combustion synthesis (SCS) using various fuels, fuel-to-oxidizer ratios, and additives. The SCS products were characterized by XRD, FTIR, N2-physisorption, SEM, DTA–TGA, and H2-TPR. It has been established that glycine provides the best yield of CeFeO3, while the addition of NH4NO3 promotes an increase in the amount of CeFeO3 by 7–12 wt%. In addition, the synthesis of CeFeO3 with the participation of NH4NO3 makes it possible to surpass the activity of the CeO2–Fe2O3 system at low temperatures (300–400 °C), as well as to increase selectivity to hydrocarbons. The observed effects are due to the increased gas evolution and ejection of reactive FeOx nanoparticles on the surface of crystallites, and an increase in the surface defects. CeFeO3 obtained in this study allows for achieving higher CO2 conversion compared to LaFeO3 at 600 °C.

This study presents Ce-Fe-O systems supported on γ-Al2O3 or SiO2 to enhance the reactivity of an oxygen-deficient CeFeO3 perovskite phase, which are promising catalysts for the production of fuels and chemicals from CO2 as feedstock. The synthesis was carried out by the glycine-nitrate solution combustion method at various fuel-to-oxidizer ratios, and with or without the addition of ammonium nitrate. The obtained composites were characterized by XRD, SEM, EDX, N2-physisorption, H2-TPR, and CO2-TPD to study the relationship of physicochemical properties with catalytic CO2 hydrogenation (rWGS) activity. γ-Al2O3 was found to be a more suitable support than SiO2 due to its ability to form a higher content of the perovskite phase, significantly reduce the size of CeFeO3 crystallites, and increase oxygen defectiveness and CO2 adsorption capacity. Combustion in the presence of silica results in the binding of most of cerium into a silicate phase, which is inactive for rWGS.

Rare-earth orthoferrites have found wide application in thermocatalytic reduction-oxidation processes. Much less attention has been paid, however, to the production of CeFeO , as well as to the study of its physicochemical and catalytic properties, in particular, in the promising process of CO utilization by hydrogenation to CO and hydrocarbons. This study presents the results of a study on the synthesis of CeFeO by solution combustion synthesis (SCS) using various fuels, fuel-to-oxidizer ratios, and additives. The SCS products were characterized by XRD, FTIR, N -physisorption, SEM, DTA-TGA, and H -TPR. It has been established that glycine provides the best yield of CeFeO , while the addition of NH NO promotes an increase in the amount of CeFeO by 7-12 wt%. In addition, the synthesis of CeFeO with the participation of NH NO makes it possible to surpass the activity of the CeO -Fe O system at low temperatures (300-400 °C), as well as to increase selectivity to hydrocarbons. The observed effects are due to the increased gas evolution and ejection of reactive FeO nanoparticles on the surface of crystallites, and an increase in the surface defects. CeFeO obtained in this study allows for achieving higher CO conversion compared to LaFeO at 600 °C.

Rare-earth orthoferrites have found wide application in thermocatalytic reduction-oxidation processes. Much less attention has been paid, however, to the production of CeFeO[sub.3] , as well as to the study of its physicochemical and catalytic properties, in particular, in the promising process of CO[sub.2] utilization by hydrogenation to CO and hydrocarbons. This study presents the results of a study on the synthesis of CeFeO[sub.3] by solution combustion synthesis (SCS) using various fuels, fuel-to-oxidizer ratios, and additives. The SCS products were characterized by XRD, FTIR, N[sub.2] -physisorption, SEM, DTA–TGA, and H[sub.2] -TPR. It has been established that glycine provides the best yield of CeFeO[sub.3] , while the addition of NH[sub.4] NO[sub.3] promotes an increase in the amount of CeFeO[sub.3] by 7–12 wt%. In addition, the synthesis of CeFeO[sub.3] with the participation of NH[sub.4] NO[sub.3] makes it possible to surpass the activity of the CeO[sub.2] –Fe[sub.2] O[sub.3] system at low temperatures (300–400 °C), as well as to increase selectivity to hydrocarbons. The observed effects are due to the increased gas evolution and ejection of reactive FeO[sub.x] nanoparticles on the surface of crystallites, and an increase in the surface defects. CeFeO[sub.3] obtained in this study allows for achieving higher CO[sub.2] conversion compared to LaFeO[sub.3] at 600 °C.