Fabio Souza Toniolo

Bio: Fabio Souza Toniolo is an academic researcher from Federal University of Rio de Janeiro. The author has contributed to research in topics: Catalysis & Carbon dioxide reforming. The author has an hindex of 10, co-authored 20 publications receiving 334 citations.

Highly active and stable Ni dispersed on mesoporous CeO2-Al2O3 catalysts for production of syngas by dry reforming of methane

Abstract: Ni-based mesoporous mixed CeO2-Al2O3 oxide catalysts prepared by one pot Evaporation Induced Self Assembly (EISA) were tested in dry reforming of methane. The textural, structural and physicochemical properties of the catalysts were studied by N2 adsorption-desorption, TEM-EDS, XRD and elemental analysis. The mobility of oxygen in the structure and the redox properties were investigated by OSCC measurements, TPR and in situ DRIFTS. Finally, the post-reaction samples were analyzed by TGA, RAMAN and TEM. The calcined catalysts prepared by EISA method present mesoporous structures with highly dispersed Ni in the form of NiAl2O4 spinel clusters. After reduction, small size metallic Ni particles are observed (

Embedded Ni nanoparticles in CeZrO2 as stable catalyst for dry reforming of methane

Abstract: Ni nanoparticles embedded in CeO2 (Ni@CeO2) and CeZrO2 (Ni@CeZrO2) were synthesized by sol-gel method and compared with a Ni/CeO2 prepared by support impregnation. The performance of the catalysts was investigated for dry reforming of methane reaction. In situ XRD, XANES and TEM showed that Ni embedded in CeO2 improved the resistance to sintering along the reduction at 800 °C. Doping ceria with zirconia inhibited the growth of Ni particles and increased the oxygen mobility. SEM, TEM, Raman spectroscopy and TGA of the used catalysts after dry reforming of methane showed that carbon formation rate was significantly reduced for the catalysts containing Ni nanoparticles embedded in ceria structure. Carbon deposits were not detected over Ni@CeZrO2 after 24 h of reaction. Therefore, the control of Ni particle size and the high oxygen mobility of Ni@CeZrO2 catalyst inhibited carbon deposition and favored the mechanism of carbon removal, promoting catalyst stability.

Structural investigation of LaCoO3 and LaCoCuO3 perovskite-type oxides and the effect of Cu on coke deposition in the partial oxidation of methane

Abstract: LaCoO 3 and LaCo 0.8 Cu 0.2 O 3 perovskite-type oxides prepared by the polymerizable complex route were obtained as single phase and investigated in the partial oxidation of methane through temperature-programmed surface reactions (TPSR). Characterizations were carried out before and after the reactions under different feed streams CH 4 /O 2 /He = 2/1/37 and 5/1/64, and revealed a dynamic structural transformation in which the perovskite is collapsed towards lanthanum-based matrix and metal cobalt and copper. The copper-substituted perovskite showed better performance in the partial oxidation of methane leading to higher CH 4 conversion and higher syngas production than LaCoO 3 during the transient reaction. Furthermore, copper had significant effect against carbon deposition on the catalyst and it is suggested to be a very important dopant for perovskites applied in reactions with hydrocarbons.

Selective CO oxidation reaction (SELOX) over cerium-doped LaCoO3 perovskite catalysts

Abstract: Perovskite-type oxides La 1− x Ce x CoO 3 ( x = 0, 0.05 and 0.10) were prepared, characterized and evaluated in the selective CO oxidation reaction (SELOX). The citrate synthesis methodology favored the formation of perovskites with rhombohedral structure and low specific surface area ( 2 g −1 ). TPR profiles showed intermediates during the reduction process but the addition of cerium not only inhibited its formation but also promoted structural modifications in the perovskite lattice. XRD diffractograms showed the formation of perovskite without phase segregation. Temperature programmed reactions showed selective CO oxidation at low temperature besides undesired reactions at higher temperatures. Catalytic tests of the SELOX reaction showed 100% of CO conversion at 200 °C. Higher temperatures favored hydrogen oxidation and methanation. Catalysts LaCoO 3 and La 0.95 Ce 0.05 CoO 3 presented good stability during 48 h of reaction. The LaCoO 3 catalyst was sensitive to the presence of H 2 O and CO 2 in the feed stream, however its CO conversion was easily restored after removing these compounds from the feed stream.

Perovskite Oxides: Preparation, Characterizations, and Applications in Heterogeneous Catalysis

Abstract: Perovskite oxides with formula ABO3 or A2BO4 are a very important class of functional materials that exhibit a range of stoichiometries and crystal structures. Because of the structural features, they could accommodate around 90% of the metallic natural elements of the Periodic Table that stand solely or partially at the A and/or B positions without destroying the matrix structure, offering a way of correlating solid state chemistry to catalytic properties. Moreover, their high thermal and hydrothermal stability enable them suitable catalytic materials either for gas or solid reactions carried out at high temperatures, or liquid reactions carried out at low temperatures. In this review, we addressed the preparation, characterization, and application of perovskite oxides in heterogeneous catalysis. Preparation is an important issue in catalysis by which materials with desired textural structure and physicochemical property could be achieved; characterization is the way to explore and understand the textura...

Fischer-tropsch synthesis: characterization and catalytic properties of rhenium promoted cobalt alumina catalysts

Abstract: Abstract The unpromoted and promoted Fischer–Tropsch synthesis (FTS) catalysts were characterized using techniques such as X-ray diffraction (XRD), temperature programmed reduction (TPR), X-ray absorption spectroscopy (XAS), Brunauer–Emmett–Teller surface area (BET SA), hydrogen chemisorption and catalytic activity using a continuously stirred tank reactor (CSTR). The addition of small amounts of rhenium to a 15% Co/Al2O3 catalyst decreased the reduction temperature of cobalt oxide but the percent dispersion and cluster size, based on the amount of reduced cobalt, did not change significantly. Samples of the catalyst were withdrawn at increasing time-on-stream from the reactor along with the wax and cooled to become embedded in the solid wax for XAS investigation. Extended X-ray absorption fine structure (EXAFS) data indicate significant cluster growth with time-on-stream suggesting a sintering process as a major source of the deactivation. Addition of rhenium increased the synthesis gas conversion, based on catalyst weight, but turnover frequencies calculated using sites from hydrogen adsorption and initial activity were similar. A wide range of synthesis gas conversion has been obtained by varying the space velocities over the catalysts.