Luanna S. Parreira

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 current (ethanol:methanol 80:20) was 4.2 mA mgPt (measured after 1800 seconds at 0.5 V). Therefore, the PtSn/C (3:1) electrocatalyst with an atomic ratio of 65:35 enhanced both the electronic effect and bifunctional mechanism in (ethanol:methanol 80:20), which resulted in the formation of CO2 at low potentials, as well as the highest amount of by-products than ethanol and methanol.

Carbon Modified with Vanadium Nanoparticles for Hydrogen Peroxide Electrogeneration

AbstractThis paper compares the results of two preparation routes for the production of carbon (Vulcan XC 72R) modified with vanadium nanostructured electrocatalysts for hydrogen peroxide (H2O2) electrogeneration using the following mass proportions of vanadium on carbon (V/C): 1, 3, 5, 7, 10, and 13%. Best results for H2O2 electrogeneration were obtained using a V/C sol-gel method (SGM) with 3%, highest ring currents. For oxygen reduction reaction (ORR), using the V/C SGM with 3% and V/C polymeric precursor method (PPM) with 7%, the results of ring currents measured are very high when compared to Vulcan XC 72R. X-ray diffraction (XRD) analysis mainly showed the V2O5 phase. X-ray photoelectron spectroscopy (XPS) results of the V/C PPM 7% and V/C SGM 3% samples highlight the predominance of the V2O5 phase and, for the latter catalyst, a more oxidized carbon surface. For the most promising electrocatalysts, the contact angle was evaluated, showing that the anchoring of the metal in the carbon surface increases the hydrophilicity of the materials. The prepared materials are promising for peroxide electrogeneration mainly due to the synergetic effect of vanadium oxide nanoparticles and acid oxygen species of the carbon, contributing to enhancing catalyst hydrophilicity. Graphical AbstractElectrocatalytic activity toward peroxide electrogeneration using V/C electrodes

Fuel Cells: Hydrogen and Ethanol Technologies

There have been many recent advances in hydrogen and ethanol-based technologies for fuel cells. Buses and hybrid cars powered by hydrogen fuel cells are increasingly common. This indicates how this has shown greater advances for stationary applications, in which more electric charge is required. Ethanol fuel cell technology is a growing field, including batteries, mobile phones, chargers, and electronic devices there are still challenges to overcome for the construction of fuel cells using both hydrogen and ethanol. However, studies have shown significant advances, which may enable this technology to dominate applications in the near future.