A hybrid membrane was synthesized by the sol-gel process using Nafion as a polymeric matrix, modified with 1% wt. of ZrO2 (N-ZrO2), the obtained membrane has a thickness of 160 μm. The proton conductivity was evaluated by four-electrode method, with relative humidity and temperature established at 50-100 % and 30-100 ˚C respectively. The hybrid membrane was compared to Nafion 115 (127 µm). The N-ZrO2 showed a proton conductivity of 0.05 S/cm (30 °C, 100 % RH), while the proton conductivity of Nafion 115 is 0.07 S/cm (30 °C, 100 % RH). First results showed a promising performance of the N-ZrO2 membrane for PEM Fuel Cells application at high temperature and low relative humidity. PEMFC performance was determined at temperatures of 30 and 100 ˚C and relative humidity of 50 and 100%, and in electrochemical hydrogen compression at 30 ˚C with a saturated gas flow of 120 ml/min.

Electrochemical energy conversion systems, mainly Unitized Regenerative Fuel Cells (URFC) and Solid Polymer Electrolyzer (SPE), are considered to have a promising future due to the generation of hydrogen in a clean and sustainable way. However, the design of oxygen electrodes is the main limiting factor for an efficient performance. In this matter, most of the studies have been focused in the development of efficient electrocatalyst for the oxygen reduction and water electrolysis reactions, and the use of electrocatalysts supports different from conventional carbon-based materials, which is susceptible of corrosion at the URFC and SPE operation conditions. Corrosion resistance supports, with improved surface area and conductivity, would reduce the electrocatalyst loading,the membrane electrode assembly degradation rate, and the global construction cost of the systems. The present work deals with the synthesis and electrochemical characterization of a Sb – doped SnO2 (ATO) for their potential use as electrocatalyst support in the oxygen electrode in electrochemical energy conversion systems. The synthesis of the support was performed by the sol –gel technique with a surface area modification with dodecylamine as surfactant followed by a thermal treatment. Electrochemical stability was evaluated by cyclic voltammetry (CV) with 250, 400 and 500 cycles in a wide range (0 – 2.0 V vs ENH), while the chronoamperometry (CA) was evaluated at high anodic potential (1.8 V vs ENH) in a continuous period of time of 5 h and 8 h. The results revealed that the Sb doped SnO2 support, present good electrical properties and electrochemical stability at a higher potential of 1.8 V vs. NHE in the presence of O2, as compared to other carbon-based and commercial sub-stoichiometric titanium oxide (Ebonex ®) supports.

This work deals with the corrosion resistance evaluation in acidic medium and electrochemical stability in a wide range (0 - 1.8 V vs ENH) for two different supports based on Sb doped SnO2 (ATO), one with low surface area (85 m2g-1) and the second one with a high surface area (216 m2g-1). Both materials were synthesized by sol - gel method and characterized by XRD, BET and HR-TEM. Both supports were compared with commercial Carbon Vulcan XC-72. The results show good chemical stability when the ATO and the modified-ATO are subjected to these conditions, whereas Vulcan carbon corrodes easily. This indicates that Sb-doped SnO2 is a good candidate for electrocatalyst supports for energy-conversion systems such as electrolysers and unified regenerative fuel cells.