The selective catalytic reduction of no over copper-containing hematite

The activity of copper-doped hematite in the SCR with propane, in the presence of oxygen, was evaluated in this work. It was found that copper sulfate led to the production of solids with different specific surface areas depending on the amount of copper. The sulfur and copper species were mainly located on the surface. The copper-containing catalysts were more active in the reduction of nitrogen oxides and less active in the propane oxidation as compared to pure hematite. This behavior was assigned to an association of both sulfur and copper species to produce new sites active for NO reduction.Facultad de Ciencias Exacta

The selective catalytic reduction of no over copper-containing hematite

The activity of copper-doped hematite in the SCR with propane, in the presence of oxygen, was evaluated in this work. It was found that copper sulfate led to the production of solids with different specific surface areas depending on the amount of copper. The sulfur and copper species were mainly located on the surface. The copper-containing catalysts were more active in the reduction of nitrogen oxides and less active in the propane oxidation as compared to pure hematite. This behavior was assigned to an association of both sulfur and copper species to produce new sites active for NO reduction.Facultad de Ciencias Exacta

Nanotecnologia: aspectos gerais e potencial de aplicação em catálise Nanotechnology: general aspects and potential applications in catalysis

In recent years nanomaterials, such as metallic nanoparticles, nanowires, nanotapes, nanotubes and nanocomposites, have attracted increasing interest for several technological applications. In catalysis, the great potential of nanomaterials is related to the high catalytic activity exhibited by these materials as a function of the high surface/volume ratio when the particles acquire diameter below 5 nm. In this work, a review about concepts and background of nanoscience and nanotechnology is presented with emphasis in catalysis. Special attention is given to gold nanoparticles and carbon nanotubes, focusing the properties and characteristics of these materials in several catalytic reactions

Cooperative effect between copper and gold on ceria for CO-PROX reaction

International audienc

Reducao catalítica seletiva de óxidos de nitrogenio sobre hematita contendo cobre

The activity of copper-doped hematite in the SCR with propane, in the presence of oxygen, was evaluated in this work. It was found that copper sulfate led to the production of solids with different specific surface areas depending on the amount of copper. The sulfur and copper species were mainly located on the surface. The copper-containing catalysts were more active in the reduction of nitrogen oxides and less active in the propane oxidation as compared to pure hematite. This behavior was assigned to an association of both sulfur and copper species to produce new sites active for NO reduction.Fil: Sousa Ferreira, Hadma. Universidade Federal da Bahia. Instituto de Química; BrasilFil: Oliveira, Soraia Jesus. Universidade Federal da Bahia. Instituto de Química; BrasilFil: Rangel, Maria do Carmo. Universidade Federal da Bahia. Instituto de Química; BrasilFil: Urquieta González, Ernesto A.. Universidade Federal de São Carlos. Departamento de Engenharia Química; BrasilFil: Martins, Leandro. Universidade Federal de São Carlos. Departamento de Engenharia Química; BrasilFil: Garcia Fierro, Jose Luis. Consejo Superior de Investigaciones Científicas. Instituto de Catálisis y Petroleoquímica; EspañaFil: Marchetti, Sergio Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

The catalytic properties of sulfated hematite in toluene disproportionation

Iron oxides are important compounds in science and technology. Due to their structural, electronic, magnetic and catalytic properties they are useful for several applications. Among them, sulfated hematite (SO4 2- /αFe2O3) is especially interesting since it shows unusual acidic properties and then behaves as a superacid solid. It is catalytically active in a large variety of reactions, such as alkane isomerization, Friedel–Crafts acylation of toluene, polymerization of ethers, benzoylation of toluene with benzoyl chloride, esterification of alcohol with acetic acid and benzylation of toluene with benzyl chloride, among others. Due to its acidic properties, sulfated hematite is also expected to be active catalyst in toluene disproportionation, an important route to obtain xylenes and benzene, high value chemicals. In order to find new catalysts for toluene disproportionation, the preparation of sulfated hematite was studied in this work. Two precursors were prepared to get the samples: iron (III) hydroxide and iron (III) hydroxoacetate, which were further heated under nitrogen. The samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, acidity measurements by temperature programmed desorption of ammonia, sulfur and carbon analyses, specific surface area measurements and Mössbauer spectroscopy. The catalysts were evaluated in toluene disproportionation at 470 °C and 1 atm, using a reaction mixture with 98% benzene and 2% 1,2,4-trimethylbenzene whose composition is close to an industrial stream, coming from naphtha reforming or naphtha pyrolysis. Different phases of iron oxides were produced, depending on the precursor. The sulfate species increased the specific surface areas and the acidity of hematite, regardless the phases produced. The iron (III) hydroxoacetate precursor was found to be the most convenient one to produce the most acid hematite with the highest specific surface area. All catalysts were active in toluene disproportionation and were selective to benzene, ethylbenzene and xylenes isomers. The sulfated catalyst prepared with iron (III) hydroxoacetate is the most selective to xylenes while both sulfate solids were selective to benzene. Therefore, iron (III) hydroxoacetate is a more efficient precursor, as compared to the traditional iron (III) hydroxide precursor, to prepare iron oxide with high specific surface areas and with more and stronger acid sites. This solid can be conveniently used to produce xylenes and benzene, high value products in chemical and petrochemical industries.Fil: Rangel, Maria do Carmo. Universidade Federal da Bahia; BrasilFil: Sousa Ferreira, Hadma. Universidade Federal da Bahia; BrasilFil: Sacramento Costa, Lílian. Universidade Federal da Bahia; BrasilFil: de Tarso Figueiredo Grecco, Saulo. Universidade Federal da Bahia; BrasilFil: Santana Oliveira, Antônia. Universidade Federal da Bahia; BrasilFil: Marchetti, Sergio Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Reyes, Patricio. Universidad de Concepción; ChileFil: Oportus, Marcelo. Universidad de Concepción; Chil