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In situ electrogeneration of hydrogen peroxide through the oxygen reduction reaction (ORR) represents a potentially greener route for wastewater treatment. However, the development of adequate catalysts following a two‐electron pathway with high selectivity and low overpotential is still of great importance. To address this issue, nanoparticles of zirconium oxide supported on reduced graphene oxide (rGO) sheets were prepared through a hydrothermal reaction, and the composite catalysts were tested for the ORR in both acid and alkaline media. The presence of zirconium oxides (ZrO2‐x and ZrO2) significantly improved the activity of rGO for the ORR and its selectivity toward H2O2 electrogeneration. Indeed, an increase from 73.7 to 89.5% was obtained in acid solution, and from 72.9 to 83.1% in alkaline medium. The high activity of the composite catalysts is assigned to the synergistic effect between ZrO2‐x and rGO. The highest selectivity for H2O2 electrogeneration was correlated to the presence of ZrO2 phase. In addition, the zirconia‐rGO catalysts are stable and reusable. Therefore, these composites are very promising catalysts to be used in gas diffusion electrodes for advanced oxidation processes.

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In this work, hydrotalcite (Mg6Al2(CO3)(OH)16•4H2O, HT-CO32-) and an hydrotalcite-like (HT-CO32--OH-) compounds were characterized and used in the fabrication of composite membranes for alkaline fuel cells. HT-CO32--OH- was prepared from commercial hydrotalcite through anion exchange. The materials were characterized by X-Ray Diffraction, Infrared Spectroscopy, CHNS Elemental Analysis, N2 sorption and Dynamic Vapor Sorption. Composite membranes were prepared by casting method using a styrene/ethylene/butylene copolymer as binder. Water up-take and OH- ion conductivity measurements were performed on two independent set of composite membranes. The partial exchange of carbonate by hydroxyl anions increases the water content in the clay gallery. Higher values of water up-take and ion conductivity were measured for the composite membranes containing the HT-CO32--OH- form.