CeFeO3–CeO2–Fe2O3 Systems: Synthesis by Solution Combustion Method and Catalytic Performance in CO2 Hydrogenation

Abstract

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.

Novel electrode material based on coral-like cerium orthoferrite (CeFeO3) for efficient alkaline water splitting

“…2,3 These compounds are characterized by a high concentration of active surface centers and exhibit remarkable activity and chemical stability in various catalytic processes, attributed to the formation of surface defects, specifically oxygen vacancies. 4,5 Moreover, because of the variety in their chemical composition and electronic structure, they can be tailored for particular catalytic applications. 1,6,7 While cerium orthoferrite (CeFeO 3 ) remains the least explored among these materials, incorporating cerium into the composition of an electrocatalyst or utilizing cerium (IV) oxide as a substrate has demonstrated a propensity to augment the reactivity of catalytic active sires in the HER process.…”

CeO2-supported Ni and Co catalysts prepared by a solution combustion method for H2production from glycerol: the effect of fuel/oxidizer ratio and oxygen excess

“…The fuel-to-oxidizer ratio ( φ ) was taken from 0.7 to 3 and calculated via the reducing and oxidizing valence states (RV and OV, respectively) according to ref. 65 and 72: φ = (−1)∑(coeff.·RV of fuel)/∑(coeff.·OV of nitrate),…”

Alumina and silica supported Ce-Fe-O systems obtained by the solution combustion method and their performance in CO2 hydrogenation to syngas

“…However, simple ferrites with unsubstituted cations, especially cerium orthoferrite, have been studied much less as catalysts than substituted perovskites, despite the extensive literature on their preparation [20][21][22][23][24][25][26]. A feature of o-CeFeO 3 A. N. Matveyeva, S. O. Omarov, M. A. Gavrilova compared to other lanthanide ferrites is the possibility of a reversible Ce 3+ ←→ Ce 4+ electronic transition, which can affect the redox properties of the perovskite and its defectiveness.…”

“…A feature of o-CeFeO 3 A. N. Matveyeva, S. O. Omarov, M. A. Gavrilova compared to other lanthanide ferrites is the possibility of a reversible Ce 3+ ←→ Ce 4+ electronic transition, which can affect the redox properties of the perovskite and its defectiveness. Recently, a sample containing 94 wt% CeFeO 3 , obtained by the solution combustion synthesis (SCS) method, was found to be highly active in rWGS [20]. Moreover, its activity is superior to LaFeO 3 , previously studied in [18].…”

“…Compared to other methods to prepare cerium orthoferrite [27][28][29][30][31][32], the SCS method is much less labor-intensive and allows one to regulate the conditions for obtaining phase-pure and homogeneous powders. An important advantage of obtaining CeFeO 3 by this method is also the option of carrying out synthesis in a reducing atmosphere created by the gaseous products of a thermochemical reaction, which is important to prevent the oxidation of perovskite at T > 350 • C [20,26].…”