The Influence of Fe Substitution in GdFeO3 on Redox and Catalytic Properties

Abstract: GdMn1 – xFexO3 (x = 0, 0.2, 0.5, 0.8, 1) perovskite oxides were prepared by a sol–gel method. The catalytic activity in dry reforming of methane was examined. XRD, BET, TPR, and TGA techniques have been used to characterize structural properties, reducibility and carbonization of the catalyst. The H2-TPR data show that an increase in the Mn content in the series of GdMn1 – xFexO3 compounds (x = 0, 0.2, 0.5, 0.8, 1) leads to a decrease in the reduction temperature. The study of the catalytic properties in the reaction of dry reforming of methane (DRM) showed that the catalytic activity of the studied compounds depends on the Fe content and increases in the series: GdMnO3 < GdMn0.8Fe0.2O3 < GdMn0.2Fe0.8O3 < GdFeO3. © 2020, Pleiades Publishing, Ltd

Effect of substituting Fe by Mn in GdFeO3 perovskite catalyst for CO hydrogenation

Gd(Fe,Mn)O3 nanoperovskites were prepared by sol-gel method and were characterized using different techniques: XRD, SEM+EDX, BET, TG to study structure and morphology. Oxidation states of Fe and Mn were determined by XPS. The performance of GdFe1-xMnxO3 perovskite catalysts with different Mn substitution levels was evaluated in the CO hydrogenаtion for light olefins production. The complex of physico-chemical methods showed that all investigated samples confirmed the presence of a single phase with perovskite-type structure. Experimental data suggested that catalysts can operate over a wide temperature range without any loss of activity and are practically unaffected by surface carbonation; their phase composition and morphology of the surface change insignificantly in catalytic processes at high temperature (~ 673 K). It was determined that the introduction of manganese into perovskite structure led to a change in the quantitative composition: the amount of butylene was much higher than that of ethylene on the samples containing manganese in the B-site. Activation of catalytic centers and their further stabilization taking place under the action of the reaction medium was established for all the systems studied. © 2019 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria

Environmental Catalysis: Dry Reforming of Methane Over (Gd,Sr)(n+1)FenO3n+1 Perovskite-type Ferrites

The perovskite-type ferrites (Gd,Sr)(n+1)FenO3n+1 (n=1, 2, infinity) were studied. Obtained catalytic properties in carbon dioxide methane reforming. It is shown that an increase in the number of perovskite layers (n) in the complex oxides structure leads to an increase in the catalytic activity. It was established that the increase of content Fe4+ in complex oxides leads to a decrease in the catalytic activity of ferrites

Effect of Cobalt in GdFeO3 Catalyst Systems on Their Activity in the Dry Reforming of Methane to Synthesis Gas

Abstract: Perovskite-type complex oxides GdFeO3 and GdCo0.5Fe0.5O3 synthesized by the sol–gel method and gadolinium ferrite modified with cobalt oxide (5 wt %) are studied as catalysts for the dry reforming of methane. Single-phase catalysts with the perovskite orthorhombic crystal structure and an average particle size of 100–200 nm are synthesized. Catalytic activity testing shows that the surface modification of gadolinium ferrite with cobalt, as well as the introduction of Co directly into the crystal structure to form a GdCo0.5Fe0.5O3 solid solution, leads to the formation of new catalytically active sites and provides an increase in the activity of GdFeO3. The sample with cobalt oxide deposited on the surface is highly resistant to coking. © 2020, Pleiades Publishing, Ltd

The performance evaluation of nanostructured perovskite-type complex oxides GdBO3 (B = Fe, Co, Mn) for carbon monoxide hydrogenation

Nanostructured perovskite-type oxides GdBO3 (B = Fe, Co, Mn) synthesized by sol-gel technology, have been used as catalysts for the light olefins production by carbon monoxide hydrogenation. Perovskite materials were characterized using different techniques: XRD, SEM+EDX, BET, TG to study structure and morphology. Oxidation state of Fe and Mn was determined by XPS. The catalytic activity test was carried out in a continuous-flow mode with chromatographic analysis of the reaction mixture. It was found that the catalytic characteristics are determined by the nature of the metal in the B-site of perovskite. The specific catalytic activity increases in the series GdMnO3 <GdFeO3 <GdCoO3, and selectivity for olefins - in the reverse order. © Published under licence by IOP Publishing Ltd