3 research outputs found
IngestĂŁo de cĂĄlcio e densidade mineral Ăłssea em mulheres adultas intolerantes Ă lactose
PtRu/C Electrocatalysts Prepared Using Gamma and Electron Beam Irradiation for Methanol Electrooxidation
PtRu/C electrocatalysts (carbon-supported PtRu nanoparticles) were prepared in a single step submitting water/2-propanol mixtures containing Pt(IV) and Ru(III) ions and the carbon support to gamma and electron beam irradiation. The electrocatalysts were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), and cyclic voltammetry and tested for methanol electrooxidation. PtRu/C electrocatalyst can be prepared in few minutes using high dose rate electron beam irradiation while using low dose rate gamma irradiation some hours were necessary to prepare it. The obtained materials showed the face-centered cubic (fcc) structure of Pt and Pt alloys with average nanoparticle sizes of around 3ânm. The material prepared using electron beam irradiation was more active for methanol electrooxidation than the material prepared using gamma irradiation
Glycerol Electrooxidation in Alkaline Medium Using Pd/C, Au/C and PdAu/C Electrocatalysts Prepared by Electron Beam Irradiation
Pd/C, Au/C and PdAu/C electrocatalysts with different atomic ratios prepared using electron beam irradiation were tested for glycerol electrooxidation in single alkaline direct glycerol fuel cell (ADGFC). X-ray diffractograms (XRD) of PdAu/C electrocatalysts showed the presence of Pd (fcc) and Au (fcc) phases. Cyclic voltammetry (CV) and chronoamperometry showed that PdAu/C electrocatalyst with Pd:Au atomic ratio of 50:50 demonstrated superior activity for glycerol electrooxidation, at room temperature. In situ Fourier transform infrared spectroscopy by attenuated total reflectance (ATR-FTIR) experiments were performed for the electrocatalysts, identifying oxalate, glycerate ion, 1,3-dihydroxy-2-propanone, glyceraldehyde and glycolate as products of glycerol electrooxidation. Experiments with single ADGFC were carried out from 50 to 90 ÂșC, using Pd/C electrocatalyst; the best performance was obtained at 80 ÂșC