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J. C. Castro R. M. Antoniassi R. R. Dias M. Linardi E. V. Spinacé A. Oliveira Neto 《Ionics》2012,18(8):781-786
PtSnRh/C-Sb2O5·SnO2 electrocatalysts with different Pt/Sn/Rh atomic ratios (90:05:05, 70:25:05, and 50:45:05) were prepared by an alcohol reduction process using H2PtCl6·6H2O, SnCl2·2H2O, RhCl3·xH2O as metal sources, ethylene glycol as solvent and reducing agent, and a physical mixture of Vulcan XC72 (85?wt%) and Sb2O5·SnO2 (15?wt%) as support. The electrocatalysts were characterized by X-ray diffraction and transmission electron microscopy. The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at 25 and 50?°C and in single direct ethanol fuel cell (DEFC) at 100?°C. The diffractograms of PtSnRh/C-Sb2O5·SnO2 electrocatalysts showed the peaks characteristic of Pt face-centered cubic structure and several others peaks associated with ·SnO2 and Sb2O5·SnO2. Transmission electron micrographs of PtSnRh/C-Sb2O5·SnO2 electrocatalysts showed the metal nanoparticles distributed on the supports with particle sizes of about 2?C3?nm. The electrochemical measurements and the experiments in a single DEFC showed that PtSnRh/C-Sb2O5·SnO2 (90:05:05) and PtSnRh/C-Sb2O5·SnO2 (70:25:05) electrocatalysts exhibited higher performance for ethanol oxidation in comparison with PtSnRh/C electrocatalyst. 相似文献
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Renata de Jesus Coelho Castro Fausto S. Sobrinho Marco A. Sundfeld da Gama Patrícia M. de Castro Barra Rosemar Antoniassi Marcone A. L. de Oliveira 《Central European Journal of Chemistry》2013,11(8):1286-1296
An alternative method for extraction optimization of C18:2 n-6 and C18:3 n-3, the main precursors for the synthesis of conjugated linoleic acid (CLA), in Brachiaria ruzizienses forages was proposed. Three methods of lipid extraction were tested: 1. Hara & Radin, 2. Micro Folch and 3. Bligh & Dyer. The preliminary test showed the Hara & Radin method as the most promising procedure. Then, a 33 Box Behnken design with triplicate in the central point was applied in Hara & Radin method in order to optimize the extraction procedure. The optimization extraction was monitored by quantification of C18:2 n-6 and C18:3 n-3 through capillary zone electrophoresis (CZE). The results obtained by CZE were compared to gas chromatography (AOCS official method) in real samples using the paired t-test. No significant difference between methods was found within a 95% confidence interval (p-value= 0.937). The alternative CZE method for Brachiaria ruzizienses forages analysis has some advantages in comparison with official GC method such as, short analysis time (10 min), no derivatization step for sample preparation, absence of specific separation columns, lower analytical cost and high throughput. 相似文献
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