Síntese e caracterização de híbridos PtRu/Carbono com diferentes cargas metálicas pelo método da carbonização hidrotérmica (original) (raw)
Related papers
Uso de baterías alcalinas agotadas para activar carbón de granza de arroz
Investigación e Innovación en Ingenierías
Objetivo: Utilizar desechos agroindustriales y baterías alcalinas agotadas como materia prima para producir carbón activado. Metodología: Como primer paso, granza de arroz fue calcinada por 6 horas a 300 °C en atmósfera de nitrógeno. Posteriormente fue activada a 600 °C por dos horas luego de ser inmersa en una disolución de ácido clorhídrico y cloruro de zinc [1,0 mol L-1]. El cloruro de zinc se obtuvo al tratar la pasta interna de baterías alcalinas agotadas con ácido clorhídrico [3,0 mol L-1]. En contraste, los activadores hidróxido de potasio, extraído de las baterías alcalinas agotadas, y el dióxido de carbono gaseoso no produjeron carbón activado bajo las mismas condiciones. Las fibras de la hoja de piña no produjeron carbón activado cuando fueron sujetas a las condiciones descritas anteriormente. Resultados: Carbón activado de granza de arroz con una superficie de 315 m2 g-1 y rico en sílice amorfo. Conclusiones: Es posible convertir granza de arroz en carbón activado con la...
Carbonized waste for the cut-down of environmental pollution with heavy metals 1
Physics of Particles and Nuclei Letters, 2011
Nowadays, an increasing concern about the treatment and disposal of waters contaminated by toxic heavy metals is noticed. The toxic pollutants must be removed from the sewage water which then is fed back into the materials cycle. Any candidate technology should result in reusable by products. With this in mind, the aim of the present study is to test a low cost procedure for utilization of the carbonized waste, a product of PET (polyethylene terephthalate) bottles pyrolysis on sand bedding, for this purpose. Both the water present in PET bottles waste and combustion exhaust probably contribute to the conversion of carbon char to activated carbon directly within the pyrolysis oven. Preliminary results, obtained for several heavy metal ions under laboratory conditions are presented and discussed. Adsorption of heavy metals on the car bonized PET waste is tested by both the electrochemical methods and X ray fluorescence spectrometry. A simple desorption procedure for the regeneration of prepared active carbon is proposed.
Chemical Engineering Journal, 2011
Hydrogen production by methane decomposition and catalytic partial oxidation of methane (CPOM) over Pt/(Ce 0.91 Gd 0.09 )O 2 − x and Pt/(Ce 0.56 Zr 0.44 )O 2 − x were studied. Results show that during the methane decomposition tests, in the absence of gaseous oxygen, hydrogen and CO were the main products and very small quantities of CO 2 were recorded. The generation of these products lasted for about 2 h, indicating that in the catalytic stability of these materials, the carrier plays an important factor. The addition of Gd and Zr cations to ceria had a positive effect on the catalysts stability. Regarding the catalytic partial oxidation of methane, a stable hydrogen production was recorded for 20 h. Here, it is proposed that the formation of a Pt-O-Ce bond causes high stability of Pt in Ce-containing supports under oxidizing conditions at high temperatures because this bond may act as an anchor, inhibiting the sintering of Pt. The deposited carbon during the catalytic tests was oxidized and the CO 2 profiles showed a sharper peak appearing at a lower temperature and a broader peak at the higher temperature. The first peak may correspond to the oxidation of coke on and in the vicinity of the metal and the second CO 2 peak may represent the coke on the carrier. The CPOM as a function of O/C ratio was studied. It was observed that the catalyst with a higher ionic conductivity, Pt/(Ce 0.91 Gd 0.09 )O 2 − x , generated a lower amount of deposited carbon.
Corrosão metálica associada ao uso de combustíveis minerais e biocombustíveis
Química Nova, 2009
Recebido em 10/11/08; aceito em 19/3/09; publicado na web em 31/8/09 METALLIC CORROSION RELATED TO MINERAL FUELS AND BIOFUELS UTILIZATION. Fuels and biofuels have a major importance in the transportation sector of any country, contributing to their economic development. The utilization of these fuels implies their closer contact to metallic materials, which comprise vehicle, storage, and transportation systems. Thus, metallic corrosion could be related to fuels and biofuels utilization. Specially, the corrosion associated to gasoline, ethanol, diesel, biodiesel, and their mixtures is discussed in this article. Briefly, the ethanol is the most corrosive and gasoline the least. Few investigations about the effect of biodiesel indicate that the corrosion is associated to their unsaturation degree and the corrosion of diesel is related to its acidity.
INGENIERÍA Y COMPETITIVIDAD
En este trabajo se estudió la transformación en fase líquida de 5 hidroximetilfurfural (5-HMF) a ácido 2,5-furandicarboxilico con el uso de catalizadores de Pt y Pd soportados en carbón activado con la presencia de NaOH ó CaCO3. Los catalizadores fueron caracterizados por quimisorción de H2 a temperatura ambiente, espectroscopia de rayos X (XPS) y análisis termogravimétrico (TGA). Los resultados indican que el tamaño de partícula de los catalizadores sigue el orden PtCl/C < PdCl/C < PdN/C el cual esta estrechamente relacionado con la actividad catalítica. Se encontró que las partículas metálicas están presentes como especies de Pd0 and Pt0. Siendo el catalizador de Pt-Cl/C con el uso de CaCO3 como aditivo.
Interactions of CO with Pt/ceria catalysts
Applied Catalysis B: Environmental, 1999
The interaction between CO and Pt/ceria catalysts was investigated by oxygen storage capacity measurements, CO and CO 2 isotope exchange and FT-IR measurements. A Pt/alumina sample was also investigated for comparison. The capacity to store and release oxygen as a function of ceria surface-area and Pt-ceria contact was estimated. The presence of chlorine from the Pt pre-cursor was found not to decrease the oxygen storage capacity. However, FT-IR measurements showed that chlorine hindered the carbonate formation during CO exposure, which was found to be the main form of carbon storage on the pre-oxidized sample. On a strongly reduced sample, CO disproportionation was found to occur to an increasing extent with increasing degree of reduction. CO and CO 2 isotope exchange showed that these molecules exchange their oxygen with Pt/ceria and ceria quite easily at 400 • C. CO chemisorption at −78 • C as a method to determine the metal dispersion was also investigated. At this temperature, the CO uptake on ceria was strongly suppressed, especially on the Cl-free sample, but not completely hindered.
Development of Carbon Materials for Energy and Environmental Applications
Catalysis Surveys from Asia, 2009
Methodologies for generating carbon materials from unusual natural sources like Limonea acidissima and Calotropis gigantea are reported. The carbon materials thus obtained have been characterized using a variety of tools. The possibility of modulating the textural properties of these materials has been examined. The carbon materials synthesized have been exploited for specific applications, such as support for noble metals for use in Direct Methanol Fuel Cells and as support for heteropoly acid for the production of gasoline additive. In addition, the utility of some of the activated carbon materials (from commercial sources) for the removal of sulphur from crude petroleum sources is also examined.