Polymeric Precursor
Mostrando 1-12 de 84 artigos, teses e dissertações.
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1. Assessment of Reaction Parameters in the Polymeric Carbon Nitride Thermal Synthesis and the Influence in Photocatalytic Hydrogen Production
In this work, the reaction parameters for polymeric carbon nitride synthesis by thermal polycondensation were assessed, such as type of precursor, heating rate and time of thermal treatment, in order to obtain crystalline materials with high photocatalytic performance. All synthesized materials were tested as photocatalysts in hydrogen production using ethyl
J. Braz. Chem. Soc.. Publicado em: 2020-05
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2. Physical and mechanical properties of low, ultralow and no cement refractory castables containing MgO nanoparticles developed in situ by means of polymeric resins
Resumo A introdução de nanopartículas de MgO desenvolvidas in situ na matriz de concretos refratários de baixo teor de cimento, ultrabaixo e sem cimento foi feita por meio de uma resina polimérica aquosa de baixa viscosidade, produzida pelo método Pechini. A adição da resina líquida aos concretos desempenhou dois papéis: primeiro serviu como fornec
Cerâmica. Publicado em: 14/11/2019
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3. Nanoparticles of Fe2O3 and Co3O4 as Efficient Electrocatalysts for Oxygen Reduction Reaction in Acid Medium
This paper presents a comparative study about the oxygen reduction reaction (ORR) catalyzed by nanoparticles of Fe2O3 and Co3O4 applied on the surface of glassy carbon electrodes (GCE). The nanoparticles were synthesized using the modified polymeric precursor method (Pechini). These two nanomaterials were characterized by Fourier transform infrared spectrosc
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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4. Síntese e caracterização de cobaltita de níquel (NiCo2O4) obtida pelométodo dos precursorespoliméricos
RESUMO A cobaltita de níquel (NiCo2O4) de estrutura do tipo espinélio apresenta baixa estabilidade térmica em torno dos 400 °C, que ocasiona a perda de NiO, afetando de maneira significativa as propriedades físicas e estruturais do material produzido. Neste trabalho a cobaltita de níquel foi preparada pelo método dos precursores poliméricos. O materi
Matéria (Rio J.). Publicado em: 16/09/2019
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5. CaTiO3 Perovskite in the Photocatalysis of Textile Wastewater
Resumo O material CaTiO3 do tipo perovskita foi sintetizado pelo método dos precursores poliméricos e caracterizado. Os parâmetros da reação fotocatalítica foram otimizados pela metodologia de análise de superfície de resposta na degradação do azul de metileno sob radiação UV. Após a otimização, as águas residuais têxteis e de curtume foram
Rev. Ambient. Água. Publicado em: 03/06/2019
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6. Performance evaluation of NiCo2O4 spinel as a catalyst for partial oxidation of methane
ABSTRACT The NiCo2O4 catalyst with spinel structure was prepared by a modified polymeric-precursor method using gelatin as an organic-directing agent. The obtained powder was characterized by XRD, TPR and tested on the partial oxidation of methane. The Rietveld analysis performed on the XRD pattern confirmed the crystallization of two phases, the spinel NiCo
Matéria (Rio J.). Publicado em: 20/05/2019
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7. Mixed Electrical Conduction of Calcium Aluminates Synthesized by Polymeric Precursors
A study of the electrical transport properties of calcium aluminate (CA) with coexisting C3A and C12A7 phases was carried out. In this work, powders resulting from synthesis based on the polymer precursor method. The resulting product was characterized by means of XRD, Raman, and UV-visible analysis to obtain the optical BG and by EIS. From the XRD and Raman
Mat. Res.. Publicado em: 23/11/2018
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8. Effect of Different Synthesis Methods on the Textural Properties of Calcium Tungstate (CaWO4) and Its Catalytic Properties in the Toluene Oxidation
Calcium tungstate (CaWO4) crystals were prepared by microwave-assisted hydrothermal (MAH) and polymeric precursor methods (PPM). These crystals were structurally characterized by X-ray diffraction (XRD), N2 adsorption, X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) measurements. The morphology and size of
Mat. Res.. Publicado em: 16/04/2018
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9. Morphological Characterization of Tungsten Trioxide Nanopowders Synthesized by Sol-Gel Modified Pechini's Method
Sol-gel modified Pechini's method was used to prepare WO3 nanopowders using dicarboxylic acid and polyethylene glycol as the chelating agent and polymeric source, respectively. WO3 powders were first prepared by calcination of resin precursor at 550ºC under various initial concentrations of metal ion (12.5-50 mmol), acid (125-500 mmol), a complexing agent (
Mat. Res.. Publicado em: 28/09/2017
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10. Evaluation of the Photocatalytic Potential of TiO2 and ZnO Obtained by Different Wet Chemical Methods
This paper describes the development of TiO2 and ZnO particles by a chemical route, using two different wet synthesis methods: polymeric precursor (PP) and sol-gel (SG). This study aimed to shed a light on how the synthesis method affects the photocatalytic activity of these oxides. Rhodamine B (RhB) degradation was used as a probe reaction to test the as-sy
Mat. Res.. Publicado em: 26/06/2017
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11. Electrooxidation of Mixed Ethanol and Methanol Solutions on PtSn/C Electrocatalysts Prepared by the Polymeric Precursor Method
Different mass ratio proportions of PtSn (m/m) electrocatalysts with 20% metal loading on a carbon support were prepared for use in ethanol:methanol solutions oxidation reactions. PtSn/C (3:1) (91% alloy degree, lattice parameter of 0.399 nm and mean crystallite size 4.8 nm) presented the best activity for oxidation of mixed solutions. The highest normalized
J. Braz. Chem. Soc.. Publicado em: 2017-06
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12. Synthesis and Structural Properties of Niobium Pentoxide Powders: A Comparative Study of the Growth Process
Powders Nb2 O5 were prepared by two different synthesis method, Sol-Gel and polymeric precursors (Pechini). In the Pechini method before adding the citric acid in the process, four different solutions were used to get the samples. For Sol-gel method, two different processes were also used in obtaining powders. The precursor was completely solubilized in etha
Mat. Res.. Publicado em: 10/10/2016